2015 |
B. Tighilet; J. Leonard; L. Bernard-Demanze; M. Lacour European Journal of Pharmacology, 769 , p. 342-349, 2015. @article{Tighilet2015, title = {Comparative analysis of pharmacological treatments with N-acetyl-DL-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat}, author = {B. Tighilet and J. Leonard and L. Bernard-Demanze and M. Lacour}, doi = {10.1016/j.ejphar.2015.11.041}, year = {2015}, date = {2015-12-15}, journal = {European Journal of Pharmacology}, volume = {769}, pages = {342-349}, abstract = {Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. Copyright © 2015 Elsevier B.V. All rights reserved. }, keywords = {}, pubstate = {published}, tppubtype = {article} } Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. Copyright © 2015 Elsevier B.V. All rights reserved. |
N. Sambucci; I. Muraccioli; B. Alescio-Lautier; V. Paban; R. Sambuc; E. Jouvé; Y. E. Geda; R. K. Petersen; B. F. Michel Subjective cognitive impairment and Alzheimer's disease: a two year follow up of 51 subjects during two years Article de journal Geriatr Psychol Neuropsychiatr Vieil., 13 (4), p. 462-471, 2015. @article{Sambucci2015z, title = {Subjective cognitive impairment and Alzheimer's disease: a two year follow up of 51 subjects during two years}, author = {N. Sambucci and I. Muraccioli and B. Alescio-Lautier and V. Paban and R. Sambuc and E. Jouvé and Y. E. Geda and R. K. Petersen and B. F. Michel}, doi = {10.1684/pnv.2015.0575}, year = {2015}, date = {2015-12-04}, journal = {Geriatr Psychol Neuropsychiatr Vieil.}, volume = {13}, number = {4}, pages = {462-471}, abstract = {Subjective cognitive impairment (SCI) is defined by a state of subjective complaint, without objective cognitive deterioration. Amnestic mild cognitive impairment (A-MCI), which characterizes a syndrome between normal cognitive aging and early Alzheimer's disease (E-AD), is preceded by A-MCI from many years. SCI expresses a metacognitive impairment. A cohort of 51 subjects [7 normal controls (NC), 28 SCI, 12 A-MCI and 5 E-AD] was followed up during 24 months, with a neuropsychological evaluation each 6 months during 1 year (V1, V2, V3), then 1 year later (V4). Among the 28 SCI, 6 converted to A-MCI at V4 (21.42%), 1 to A-MCI-A at V3, then to E-AD at V4. These results suggest a continuum from SCI to A-MCI, and E-AD. Progressive SCI differed from non-progressive SCI on verbal episodic memory and executive functions tests at the initial examination. MRI showed anterior cingular atrophy in all SCI patients but hippocampal atrophy was only observed in 20 patients. Our results suggest that metacognition impairment is the expression of a dysfunction in the anterior pre-frontal cortex, in correlation with a syndrome of hyper-attention.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Subjective cognitive impairment (SCI) is defined by a state of subjective complaint, without objective cognitive deterioration. Amnestic mild cognitive impairment (A-MCI), which characterizes a syndrome between normal cognitive aging and early Alzheimer's disease (E-AD), is preceded by A-MCI from many years. SCI expresses a metacognitive impairment. A cohort of 51 subjects [7 normal controls (NC), 28 SCI, 12 A-MCI and 5 E-AD] was followed up during 24 months, with a neuropsychological evaluation each 6 months during 1 year (V1, V2, V3), then 1 year later (V4). Among the 28 SCI, 6 converted to A-MCI at V4 (21.42%), 1 to A-MCI-A at V3, then to E-AD at V4. These results suggest a continuum from SCI to A-MCI, and E-AD. Progressive SCI differed from non-progressive SCI on verbal episodic memory and executive functions tests at the initial examination. MRI showed anterior cingular atrophy in all SCI patients but hippocampal atrophy was only observed in 20 patients. Our results suggest that metacognition impairment is the expression of a dysfunction in the anterior pre-frontal cortex, in correlation with a syndrome of hyper-attention. |
L. Pourcin; L. Springer-Charolles; A. El Ahmadi; P. Cole Reading and related skills in Grades 6, 7, 8 and 9: French normative data from EVALEC Article de journal Revue Européenne de Psychologie Appliquée/European Review of Applied Psychology, 1780 (1), p. 23-37, 2015. @article{Pourcin2015, title = {Reading and related skills in Grades 6, 7, 8 and 9: French normative data from EVALEC}, author = {L. Pourcin and L. Springer-Charolles and A. El Ahmadi and P. Cole}, doi = {10.1016/j.erap.2015.11.002}, year = {2015}, date = {2015-11-10}, journal = {Revue Européenne de Psychologie Appliquée/European Review of Applied Psychology}, volume = {1780}, number = {1}, pages = {23-37}, abstract = {Introduction To appropriately assess reading difficulties, tests designed according to an appropriate theoretical framework and based on normative data are required. Objective We used EVALEC (Sprenger-Charolles, Colé, Béchennec, & Kipffer-Piquard, 2005) to collect data on the word-level reading skills and reading-related skills (phonemic awareness, phonological short-term memory, and rapid naming) of middle school children (Grades 6 to 9, about 80 in each grade). Method In the tests focused on word-level reading skills, the effects of regularity (regular vs. irregular words), lexicality, and length (short vs. long irregular words and pseudowords) were examined. Accuracy and processing times were recorded for all tests. Results The effects of both regularity and lexicality were significant, whatever the measure and independently of grade. Both accuracy and speed were lower for longer pseudowords, whereas length did not have a significant effect on irregular word latencies and, surprisingly, long irregular words were read more accurately than short ones. Reading level as assessed by a standardized test (Lefavrais, 2005) was not predicted by phonological short-term memory; rapid naming (color names) and phonemic awareness were both predictors but, in both cases, only response times predicted reading level. Conclusion These results, and particularly those from the reading tasks, are discussed in relation to models of written-word recognition developed to account for the reading of multisyllabic items (Perry, Ziegler, & Zorzi, 2010) in orthographies shallower than English (Perry, Ziegler, & Zorzi, 2014). Résumé Introduction Des tests conçus selon un cadre théorique approprié et sur la base de données normatives sont nécessaires pour évaluer correctement les difficultés de lecture. Objectif Nous avons utilisé EVALEC (Sprenger-Charolles, Colé, Béchennec, & Kipffer-Piquard, 2005) pour recueillir des données sur les capacités d’identification de mots écrits et celles reliées à la lecture (conscience phonémique, mémoire à court terme phonologique et dénomination rapide) au collège (du grade 6 au grade 9, environ 80 enfants par grade). Méthode Pour les tests évaluant les capacités d’identification de mots écrits, les effets de régularité (mots réguliers vs mots irréguliers), de lexicalité, et de longueur (mots irréguliers courts vs longs comparés à pseudomots court vs long) ont été examinés. Pour tous les tests, la précision et le temps de traitement ont été enregistrés. Résultats Les effets de régularité et lexicalité étaient significatifs, quels que soient la mesure et le grade. Les scores de précision et de vitesse étaient plus faibles pour les pseudomots longs, alors que la longueur n’a pas eu d’effet significatif sur les temps de latences des mots irréguliers et, étonnamment, les mots irréguliers longs ont été lus avec plus de précision que les courts. Le niveau de lecture évalué par un test standardisé (Lefavrais, 2005) n’a pas été prédit par la mémoire à court terme phonologique ; la dénomination rapide (des noms de couleur) et la conscience phonémique étaient deux prédicteurs mais seulement lorsque les temps de réponse pour ces deux tests ont été analysés. Conclusion Ces résultats, et en particulier ceux des tests de lecture, sont discutés en relation avec les modèles de reconnaissance des mots écrits développés pour rendre compte de la lecture d’items multisyllabiques (Perry, Ziegler, & Zorzi, 2010) dans des orthographes moins profondes que celles de l’anglais (Perry, Ziegler, & Zorzi, 2014).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Introduction To appropriately assess reading difficulties, tests designed according to an appropriate theoretical framework and based on normative data are required. Objective We used EVALEC (Sprenger-Charolles, Colé, Béchennec, & Kipffer-Piquard, 2005) to collect data on the word-level reading skills and reading-related skills (phonemic awareness, phonological short-term memory, and rapid naming) of middle school children (Grades 6 to 9, about 80 in each grade). Method In the tests focused on word-level reading skills, the effects of regularity (regular vs. irregular words), lexicality, and length (short vs. long irregular words and pseudowords) were examined. Accuracy and processing times were recorded for all tests. Results The effects of both regularity and lexicality were significant, whatever the measure and independently of grade. Both accuracy and speed were lower for longer pseudowords, whereas length did not have a significant effect on irregular word latencies and, surprisingly, long irregular words were read more accurately than short ones. Reading level as assessed by a standardized test (Lefavrais, 2005) was not predicted by phonological short-term memory; rapid naming (color names) and phonemic awareness were both predictors but, in both cases, only response times predicted reading level. Conclusion These results, and particularly those from the reading tasks, are discussed in relation to models of written-word recognition developed to account for the reading of multisyllabic items (Perry, Ziegler, & Zorzi, 2010) in orthographies shallower than English (Perry, Ziegler, & Zorzi, 2014). Résumé Introduction Des tests conçus selon un cadre théorique approprié et sur la base de données normatives sont nécessaires pour évaluer correctement les difficultés de lecture. Objectif Nous avons utilisé EVALEC (Sprenger-Charolles, Colé, Béchennec, & Kipffer-Piquard, 2005) pour recueillir des données sur les capacités d’identification de mots écrits et celles reliées à la lecture (conscience phonémique, mémoire à court terme phonologique et dénomination rapide) au collège (du grade 6 au grade 9, environ 80 enfants par grade). Méthode Pour les tests évaluant les capacités d’identification de mots écrits, les effets de régularité (mots réguliers vs mots irréguliers), de lexicalité, et de longueur (mots irréguliers courts vs longs comparés à pseudomots court vs long) ont été examinés. Pour tous les tests, la précision et le temps de traitement ont été enregistrés. Résultats Les effets de régularité et lexicalité étaient significatifs, quels que soient la mesure et le grade. Les scores de précision et de vitesse étaient plus faibles pour les pseudomots longs, alors que la longueur n’a pas eu d’effet significatif sur les temps de latences des mots irréguliers et, étonnamment, les mots irréguliers longs ont été lus avec plus de précision que les courts. Le niveau de lecture évalué par un test standardisé (Lefavrais, 2005) n’a pas été prédit par la mémoire à court terme phonologique ; la dénomination rapide (des noms de couleur) et la conscience phonémique étaient deux prédicteurs mais seulement lorsque les temps de réponse pour ces deux tests ont été analysés. Conclusion Ces résultats, et en particulier ceux des tests de lecture, sont discutés en relation avec les modèles de reconnaissance des mots écrits développés pour rendre compte de la lecture d’items multisyllabiques (Perry, Ziegler, & Zorzi, 2010) dans des orthographes moins profondes que celles de l’anglais (Perry, Ziegler, & Zorzi, 2014). |
S. Besnard; C. Lopez; T. Brandt; P. Denise; P. F. Smith Editorial: The Vestibular System in Cognitive and Memory Processes in Mammalians Article de journal Frontiers in Integrative Neuroscience, 2015. @article{Besnard2015, title = {Editorial: The Vestibular System in Cognitive and Memory Processes in Mammalians}, author = {S. Besnard and C. Lopez and T. Brandt and P. Denise and P. F. Smith}, doi = {10.3389/fnint.2015.00055}, year = {2015}, date = {2015-11-10}, journal = {Frontiers in Integrative Neuroscience}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Y. Cazals; M. Bévengut; S. Zanella; F. Brocard; J. Barhanin; C. Gestreau KCNK5 channels mostly expressed in cochlear outer sulcus cells are indispensable for hearing Article de journal Nature Communications, 2015. @article{Cazals2015, title = {KCNK5 channels mostly expressed in cochlear outer sulcus cells are indispensable for hearing}, author = {Y. Cazals and M. Bévengut and S. Zanella and F. Brocard and J. Barhanin and C. Gestreau}, doi = {10.1038/ncomms9780}, year = {2015}, date = {2015-10-01}, journal = {Nature Communications}, abstract = {In the cochlea, K(+) is essential for mechano-electrical transduction. Here, we explore cochlear structure and function in mice lacking K(+) channels of the two-pore domain family. A profound deafness associated with a decrease in endocochlear potential is found in adult Kcnk5(-/-) mice. Hearing occurs around postnatal day 19 (P19), and completely disappears 2 days later. At P19, Kcnk5(-/-) mice have a normal endolymphatic [K(+)] but a partly lowered endocochlear potential. Using Lac-Z as a gene reporter, KCNK5 is mainly found in outer sulcus Claudius', Boettcher's and root cells. Low levels of expression are also seen in the spiral ganglion, Reissner's membrane and stria vascularis. Essential channels (KCNJ10 and KCNQ1) contributing to K(+) secretion in stria vascularis have normal expression in Kcnk5(-/-) mice. Thus, KCNK5 channels are indispensable for the maintenance of hearing. Among several plausible mechanisms, we emphasize their role in K(+) recycling along the outer sulcus lateral route.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the cochlea, K(+) is essential for mechano-electrical transduction. Here, we explore cochlear structure and function in mice lacking K(+) channels of the two-pore domain family. A profound deafness associated with a decrease in endocochlear potential is found in adult Kcnk5(-/-) mice. Hearing occurs around postnatal day 19 (P19), and completely disappears 2 days later. At P19, Kcnk5(-/-) mice have a normal endolymphatic [K(+)] but a partly lowered endocochlear potential. Using Lac-Z as a gene reporter, KCNK5 is mainly found in outer sulcus Claudius', Boettcher's and root cells. Low levels of expression are also seen in the spiral ganglion, Reissner's membrane and stria vascularis. Essential channels (KCNJ10 and KCNQ1) contributing to K(+) secretion in stria vascularis have normal expression in Kcnk5(-/-) mice. Thus, KCNK5 channels are indispensable for the maintenance of hearing. Among several plausible mechanisms, we emphasize their role in K(+) recycling along the outer sulcus lateral route. |
Brandon J. Farley; Arnaud J. Noreña Membrane potential dynamics of populations of cortical neurons during auditory streaming Article de journal Journal of Neurophysiology, 2015. @article{Farley2015, title = {Membrane potential dynamics of populations of cortical neurons during auditory streaming}, author = {Brandon J. Farley and Arnaud J. Noreña}, doi = {10.1152/jn.00545.2015}, year = {2015}, date = {2015-10-01}, journal = {Journal of Neurophysiology}, abstract = {How a mixture of acoustic sources is perceptually organized into discrete auditory objects remains unclear. One current hypothesis postulates that perceptual segregation of different sources is related to the spatiotemporal separation of cortical responses induced by each acoustic source or stream. In the present study, the dynamics of subthreshold membrane potential activity were measured across the entire tonotopic axis of the rodent primary auditory cortex during the auditory streaming paradigm using voltage-sensitive dye imaging. Consistent with the proposed hypothesis, we observed enhanced spatiotemporal segregation of cortical responses to alternating tone sequences as their frequency separation or presentation rate was increased, both manipulations known to promote stream segregation. However, across most streaming paradigm conditions tested, a substantial cortical region maintaining a response to both tones coexisted with more peripheral cortical regions responding more selectively to one of them. We propose that these coexisting subthreshold representation types could provide neural substrates to support the flexible switching between the integrated and segregated streaming percepts. Copyright © 2015 the American Physiological Society.}, key = {auditory scene analysis; bistability; cocktail party; neural adaptation; perceptual segregation}, keywords = {}, pubstate = {published}, tppubtype = {article} } How a mixture of acoustic sources is perceptually organized into discrete auditory objects remains unclear. One current hypothesis postulates that perceptual segregation of different sources is related to the spatiotemporal separation of cortical responses induced by each acoustic source or stream. In the present study, the dynamics of subthreshold membrane potential activity were measured across the entire tonotopic axis of the rodent primary auditory cortex during the auditory streaming paradigm using voltage-sensitive dye imaging. Consistent with the proposed hypothesis, we observed enhanced spatiotemporal segregation of cortical responses to alternating tone sequences as their frequency separation or presentation rate was increased, both manipulations known to promote stream segregation. However, across most streaming paradigm conditions tested, a substantial cortical region maintaining a response to both tones coexisted with more peripheral cortical regions responding more selectively to one of them. We propose that these coexisting subthreshold representation types could provide neural substrates to support the flexible switching between the integrated and segregated streaming percepts. Copyright © 2015 the American Physiological Society. |
C. Lopez; C. J. Falconer; D. Deroualle; F. W. Mast In the presence of others: self-location, balance control and vestibular processing Article de journal Neurophysiologie Clinique/Clinical Neurophysiology, 45 (4-5), p. 241-254, 2015. @article{Lopez2015b, title = {In the presence of others: self-location, balance control and vestibular processing}, author = {C. Lopez and C. J. Falconer and D. Deroualle and F. W. Mast}, doi = {10.1016/j.neucli.2015.09.001}, year = {2015}, date = {2015-09-11}, journal = {Neurophysiologie Clinique/Clinical Neurophysiology}, volume = {45}, number = {4-5}, pages = {241-254}, abstract = {The degree to which others in our environment influence sensorimotor processing has been a particular focus of cognitive neuroscience for the past two decades. This process of self-other resonance, or shared body representation, has only recently been extended to more global bodily processes such as self-location, self-motion perception, balance and perspective taking. In this review, we outline these previously overlooked areas of research to bridge the distinct field of social neuroscience with global self-perception, vestibular processing and postural control. Firstly, we outline research showing that the presence and movement of others can modulate two fundamental experiences of the self: self-location (the experience of where the self is located in space) and self-motion perception (the experience that oneself has moved or has been moved in space). Secondly, we outline recent research that has shown perturbations in balance control as a result of instability in others in our environment. Conversely to this, we also highlight studies in virtual reality demonstrating the potential benefits of the presence of others in our environment for those undergoing vestibular rehabilitation. Thirdly, we outline studies of first- and third-person perspective taking, which is the ability to have or take a visuo-spatial perspective within and out-with the confines of our own body. These studies demonstrate a contamination of perspective taking processes (i.e. automatic, implicit, third-person perspective taking) in the presence of others. This collection of research highlights the importance of social cues in the more global processing of the self and its accompanying sensory inputs, particularly vestibular signals. Future research will need to better determine the mechanisms of self-other resonance within these processes, including the role of individual differences in the susceptibility to the influence of another. Copyright © 2015 Elsevier Masson SAS. All rights reserved. }, keywords = {}, pubstate = {published}, tppubtype = {article} } The degree to which others in our environment influence sensorimotor processing has been a particular focus of cognitive neuroscience for the past two decades. This process of self-other resonance, or shared body representation, has only recently been extended to more global bodily processes such as self-location, self-motion perception, balance and perspective taking. In this review, we outline these previously overlooked areas of research to bridge the distinct field of social neuroscience with global self-perception, vestibular processing and postural control. Firstly, we outline research showing that the presence and movement of others can modulate two fundamental experiences of the self: self-location (the experience of where the self is located in space) and self-motion perception (the experience that oneself has moved or has been moved in space). Secondly, we outline recent research that has shown perturbations in balance control as a result of instability in others in our environment. Conversely to this, we also highlight studies in virtual reality demonstrating the potential benefits of the presence of others in our environment for those undergoing vestibular rehabilitation. Thirdly, we outline studies of first- and third-person perspective taking, which is the ability to have or take a visuo-spatial perspective within and out-with the confines of our own body. These studies demonstrate a contamination of perspective taking processes (i.e. automatic, implicit, third-person perspective taking) in the presence of others. This collection of research highlights the importance of social cues in the more global processing of the self and its accompanying sensory inputs, particularly vestibular signals. Future research will need to better determine the mechanisms of self-other resonance within these processes, including the role of individual differences in the susceptibility to the influence of another. Copyright © 2015 Elsevier Masson SAS. All rights reserved. |
E. Ribot-Ciscar; V. Milhe-De Bovis; J-M. Aimonetti; B. Lapeyssonnie; E. Campana-Salort; J. Pouget; S. Attarian Functional impact of vibratory proprioceptive assistance in patients with facioscapulohumeral muscular dystrophy Article de journal Muscle and Nerve, 52 , p. 780-787, 2015. @article{Ribot-Ciscar2015, title = {Functional impact of vibratory proprioceptive assistance in patients with facioscapulohumeral muscular dystrophy}, author = {E. Ribot-Ciscar and V. Milhe-De Bovis and J-M. Aimonetti and B. Lapeyssonnie and E. Campana-Salort and J. Pouget and S. Attarian }, doi = {10.1002/mus.24605}, year = {2015}, date = {2015-09-03}, journal = {Muscle and Nerve}, volume = {52}, pages = {780-787}, abstract = {INTRODUCTION: In this study we analyzed the effects of a rehabilitation method based on the use of vibratory proprioceptive assistance (VPA) in subjects with facioscapulohumeral muscular dystrophy. METHODS: Eight subjects were given 1 month of mechanical vibratory treatment that consisted of 8 sessions of 40-min stimulation on the more affected side. During each session, illusory movements were induced as follows: sensations of extension or flexion of the forearm or elevation of the arm via vibration applied to the distal tendon of the biceps brachialis (BB), triceps brachialis (TB), or pectoralis major muscles (PM), respectively, and of elevation of the arm with extension or flexion of the forearm via vibration of PM+BB or PM+TB, respectively. RESULTS: Treatment led to a significant increase in the amplitude of voluntary shoulder flexion, constant score, and self-rated health. CONCLUSION: VPA may serve as a rehabilitation method for reducing the deleterious effects of decline in motor activities. © 2015 Wiley Periodicals, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } INTRODUCTION: In this study we analyzed the effects of a rehabilitation method based on the use of vibratory proprioceptive assistance (VPA) in subjects with facioscapulohumeral muscular dystrophy. METHODS: Eight subjects were given 1 month of mechanical vibratory treatment that consisted of 8 sessions of 40-min stimulation on the more affected side. During each session, illusory movements were induced as follows: sensations of extension or flexion of the forearm or elevation of the arm via vibration applied to the distal tendon of the biceps brachialis (BB), triceps brachialis (TB), or pectoralis major muscles (PM), respectively, and of elevation of the arm with extension or flexion of the forearm via vibration of PM+BB or PM+TB, respectively. RESULTS: Treatment led to a significant increase in the amplitude of voluntary shoulder flexion, constant score, and self-rated health. CONCLUSION: VPA may serve as a rehabilitation method for reducing the deleterious effects of decline in motor activities. © 2015 Wiley Periodicals, Inc. |
Dubois B; Chupin M; Hampel H; Lista S; Cavedo E; Croisile B; Louis Tisserand G; Touchon J; Bonafe A; Ousset P.J; Ait Ameur A; Rouaud O; Ricolfi F; Vighetto A; Pasquier F; Delmaire C; Ceccaldi M; Girard N; Dufouil C; Lehericy S; Tonelli I; Duveau F; Colliot O; Garnero L; Sarazin M; Dormont D; Hippocampus Study Group Donepezil decreases annual rate of hippocampal atrophy in suspected prodromal Alzheimer's disease. Article de journal Alzheimer's & Dementia, 11 (9), p. 1041-1049, 2015. @article{Dubois2015, title = {Donepezil decreases annual rate of hippocampal atrophy in suspected prodromal Alzheimer's disease.}, author = {Dubois B and Chupin M and Hampel H and Lista S and Cavedo E and Croisile B and Louis Tisserand G and Touchon J and Bonafe A and Ousset P.J and Ait Ameur A and Rouaud O and Ricolfi F and Vighetto A and Pasquier F and Delmaire C and Ceccaldi M and Girard N and Dufouil C and Lehericy S and Tonelli I and Duveau F and Colliot O and Garnero L and Sarazin M and Dormont D and Hippocampus Study Group}, doi = {10.1016/j.jalz.2014.10.003}, year = {2015}, date = {2015-09-01}, journal = {Alzheimer's & Dementia}, volume = {11}, number = {9}, pages = {1041-1049}, abstract = {Introduction The purpose of this study was to study the effect of donepezil on the rate of hippocampal atrophy in prodromal Alzheimer's disease (AD). Methods A double-blind, randomized, placebo-controlled parallel group design using donepezil (10 mg/day) in subjects with suspected prodromal AD. Subjects underwent two brain magnetic resonance imaging scans (baseline and final visit). The primary efficacy outcome was the annualized percentage change (APC) of total hippocampal volume (left + right) measured by an automated segmentation method. Results Two-hundred and sixteen only subjects were randomized across 28 French expert clinical sites. In the per protocol population (placebo = 92 and donepezil = 82), the donepezil group exhibited a significant reduced rate of hippocampal atrophy (APC = −1.89%) compared with the placebo group (APC = −3.47%), P < .001. There was no significant difference in neuropsychological performance between treatment groups. Discussion A 45% reduction of rate of hippocampal atrophy was observed in prodromal AD following 1 year of treatment with donepezil compared with placebo.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Introduction The purpose of this study was to study the effect of donepezil on the rate of hippocampal atrophy in prodromal Alzheimer's disease (AD). Methods A double-blind, randomized, placebo-controlled parallel group design using donepezil (10 mg/day) in subjects with suspected prodromal AD. Subjects underwent two brain magnetic resonance imaging scans (baseline and final visit). The primary efficacy outcome was the annualized percentage change (APC) of total hippocampal volume (left + right) measured by an automated segmentation method. Results Two-hundred and sixteen only subjects were randomized across 28 French expert clinical sites. In the per protocol population (placebo = 92 and donepezil = 82), the donepezil group exhibited a significant reduced rate of hippocampal atrophy (APC = −1.89%) compared with the placebo group (APC = −3.47%), P < .001. There was no significant difference in neuropsychological performance between treatment groups. Discussion A 45% reduction of rate of hippocampal atrophy was observed in prodromal AD following 1 year of treatment with donepezil compared with placebo. |
A. Devèze; M. Montava; C. Lopez; M. Lacour; J. Magnan; L. Borel Vestibular compensation following vestibular neurotomy Article de journal European Annals of Otorhinolaryngology, Head and Neck Diseases, 132 (4), p. 197-203, 2015. @article{Deveze2015, title = {Vestibular compensation following vestibular neurotomy}, author = {A. Devèze and M. Montava and C. Lopez and M. Lacour and J. Magnan and L. Borel}, doi = {10.1016/j.anorl.2015.04.003}, year = {2015}, date = {2015-09-01}, journal = {European Annals of Otorhinolaryngology, Head and Neck Diseases}, volume = {132}, number = {4}, pages = {197-203}, abstract = {Objectives Four studies assessing vestibular compensation in Menière's disease patients undergoing unilateral vestibular neurotomy, using different analysis methods, are reviewed, with a focus on the different strategies used by patients according to their preoperative sensory preference. Material and methods Four prospective studies performed in a university tertiary referral center were reviewed, measuring the pattern of vestibular compensation in Menière's disease patients before and after unilateral vestibular neurotomy on various assessment protocols: postural syndrome assessed on static posturography and gait analysis; perceptual syndrome assessed on subjective visual vertical perception; and oculomotor syndrome assessed on ocular cyclotorsion. Results Vestibular compensation occurred at variable intervals depending on the parameter investigated. Open-eye postural control and gait/walking returned to normal one month after neurotomy. Fine balance analysis found that visual perception of the vertical and ocular cyclotorsion impairment persisted at long-term follow-up. Clinical postural disturbance persisted only when visual afferents were cut off (eyes closed). These impairments were the expression of a postoperative change in postural strategy related to the new use of visual and non-visual references. Conclusions Understanding pre-operative interindividual variation in balance strategy is critical to screening for postural instability and tailoring vestibular rehabilitation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objectives Four studies assessing vestibular compensation in Menière's disease patients undergoing unilateral vestibular neurotomy, using different analysis methods, are reviewed, with a focus on the different strategies used by patients according to their preoperative sensory preference. Material and methods Four prospective studies performed in a university tertiary referral center were reviewed, measuring the pattern of vestibular compensation in Menière's disease patients before and after unilateral vestibular neurotomy on various assessment protocols: postural syndrome assessed on static posturography and gait analysis; perceptual syndrome assessed on subjective visual vertical perception; and oculomotor syndrome assessed on ocular cyclotorsion. Results Vestibular compensation occurred at variable intervals depending on the parameter investigated. Open-eye postural control and gait/walking returned to normal one month after neurotomy. Fine balance analysis found that visual perception of the vertical and ocular cyclotorsion impairment persisted at long-term follow-up. Clinical postural disturbance persisted only when visual afferents were cut off (eyes closed). These impairments were the expression of a postoperative change in postural strategy related to the new use of visual and non-visual references. Conclusions Understanding pre-operative interindividual variation in balance strategy is critical to screening for postural instability and tailoring vestibular rehabilitation. |
C. Chabbert Anatomie et physiologie du vestibule Article de journal EM Consulte Oto-Rhino-Laryngologie, 2015. @article{Chabbert2015, title = {Anatomie et physiologie du vestibule}, author = {C. Chabbert}, doi = {10.1016/S0246-0351(15)58501-2}, year = {2015}, date = {2015-08-31}, journal = {EM Consulte Oto-Rhino-Laryngologie}, abstract = {La présente revue ambitionne de faire un point sur la physiologie du vestibule. L'idée n'est pas de reproduire ici les différentes présentations déjà disponibles dans de nombreux ouvrages de physiologie ou de médecine ou sur divers sites Internet, mais plutôt d'apporter un regard différent, plus mécanistique et moléculaire, en explorant le fonctionnement du vestibule « de l'intérieur ». Par cette approche, nous tenterons de décrire les principes et limites physiques qui gouvernent les processus de mise en place de l'information sensorielle vestibulaire. Nous présenterons également plusieurs approches technologiques originales qu'il a été nécessaire de développer pour appréhender les caractéristiques morphofonctionnelles des organes vestibulaires. Cette démarche a pour objectif de susciter l'intérêt, mais aussi de promouvoir de nouvelles questions et projets d'étude sur le fonctionnement de cet organe original qui ne cesse d'étonner.}, key = {Vestibule, Transduction mécanoélectrique, Otoconies, Endolymphe, Synapses en ruban}, keywords = {}, pubstate = {published}, tppubtype = {article} } La présente revue ambitionne de faire un point sur la physiologie du vestibule. L'idée n'est pas de reproduire ici les différentes présentations déjà disponibles dans de nombreux ouvrages de physiologie ou de médecine ou sur divers sites Internet, mais plutôt d'apporter un regard différent, plus mécanistique et moléculaire, en explorant le fonctionnement du vestibule « de l'intérieur ». Par cette approche, nous tenterons de décrire les principes et limites physiques qui gouvernent les processus de mise en place de l'information sensorielle vestibulaire. Nous présenterons également plusieurs approches technologiques originales qu'il a été nécessaire de développer pour appréhender les caractéristiques morphofonctionnelles des organes vestibulaires. Cette démarche a pour objectif de susciter l'intérêt, mais aussi de promouvoir de nouvelles questions et projets d'étude sur le fonctionnement de cet organe original qui ne cesse d'étonner. |
D. Deroualle; L. Borel; A. Devèze; C. Lopez Changing perspective: The role of vestibular signals. Article de journal Neuropsychologia, 15 , 2015, ISBN: S0028-3932. @article{Deroualle2015, title = {Changing perspective: The role of vestibular signals.}, author = {D. Deroualle and L. Borel and A. Devèze and C. Lopez}, url = {http://www.sciencedirect.com/science/article/pii/S002839321530138X}, doi = {10.1016/j.neuropsychologia.2015.08.022.}, isbn = {S0028-3932}, year = {2015}, date = {2015-08-24}, journal = {Neuropsychologia}, volume = {15}, abstract = {Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others' actions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others' actions. |
D. Deroualle; L. Borel; A. Devèze; C. Lopez Changing perspective: the role of vestibular signals Article de journal Neuropsychologia, 79 (Part B) , p. 175-185, 2015. @article{Deroualle2015b, title = {Changing perspective: the role of vestibular signals}, author = {D. Deroualle and L. Borel and A. Devèze and C. Lopez}, doi = {10.1016/j.neuropsychologia.2015.08.022}, year = {2015}, date = {2015-08-21}, journal = {Neuropsychologia}, volume = {79 (Part B)}, pages = {175-185}, abstract = {Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others’ actions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others’ actions. |
Le Ber I.; De Septenville A.; Millecamps S.; Camuzat A.; Caroppo P.; Couratier P.; Blanc F.; Lacomblez L.; Sellal F.; Fleury M.C.; Meininger V.; Cazeneuve C.; Clot F.; Flabeau O.; LeGuern E.; Brice A.; French Clinical & Genetic Research Network on FTLD/FTLD-ALS TBK1 mutation frequencies in French fronto-temporal dementia and amyotrophic lateral sclerosis cohorts. Article de journal Neurobiology of Aging, 36 (11), p. 3116.e5–3116.e8, 2015. @article{LeBer2015, title = {TBK1 mutation frequencies in French fronto-temporal dementia and amyotrophic lateral sclerosis cohorts.}, author = {Le Ber I. and De Septenville A. and Millecamps S. and Camuzat A. and Caroppo P. and Couratier P. and Blanc F. and Lacomblez L. and Sellal F. and Fleury M.C. and Meininger V. and Cazeneuve C. and Clot F. and Flabeau O. and LeGuern E. and Brice A. and French Clinical & Genetic Research Network on FTLD/FTLD-ALS}, doi = {10.1016/j.neurobiolaging.2015.08.009}, year = {2015}, date = {2015-08-08}, journal = {Neurobiology of Aging}, volume = {36}, number = {11}, pages = {3116.e5–3116.e8}, abstract = {TANK1-binding kinase 1 (TBK1) has been recently identified as a new amyotrophic lateral sclerosis (ALS) gene. Loss-of-function (LoF) mutations in TBK1 could be responsible for 0.4%–4% of ALS. Considering the strong genetic overlap existing between frontotemporal dementia (FTD) and ALS, we have evaluated the frequencies of TBK1 mutations in a cohort of French FTD and of ALS patients. We identified 5 LoF mutations, in 4 FTD-ALS and 1 ALS patients. We also identified 5 heterozygous missense variants, predicted to be deleterious, in 1 isolated FTD, 1 FTD-ALS, and 3 ALS cases. Our results demonstrate that TBK1 loss-of-function mutations are more frequent in patients with FTD-ALS (10.8%) than in isolated ALS. TBK1 should thus also be sequenced, after exclusion of C9orf72 mutation, in patients presenting FTD, particularly in cases secondarily associated with ALS.}, keywords = {}, pubstate = {published}, tppubtype = {article} } TANK1-binding kinase 1 (TBK1) has been recently identified as a new amyotrophic lateral sclerosis (ALS) gene. Loss-of-function (LoF) mutations in TBK1 could be responsible for 0.4%–4% of ALS. Considering the strong genetic overlap existing between frontotemporal dementia (FTD) and ALS, we have evaluated the frequencies of TBK1 mutations in a cohort of French FTD and of ALS patients. We identified 5 LoF mutations, in 4 FTD-ALS and 1 ALS patients. We also identified 5 heterozygous missense variants, predicted to be deleterious, in 1 isolated FTD, 1 FTD-ALS, and 3 ALS cases. Our results demonstrate that TBK1 loss-of-function mutations are more frequent in patients with FTD-ALS (10.8%) than in isolated ALS. TBK1 should thus also be sequenced, after exclusion of C9orf72 mutation, in patients presenting FTD, particularly in cases secondarily associated with ALS. |
A. Gay; J-M. Aimonetti; J-P. Roll; E. Ribot-Ciscar Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation Article de journal Brain Research, 1615 , p. 148–156, 2015. @article{Gay2015, title = {Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation}, author = {A. Gay and J-M. Aimonetti and J-P. Roll and E. Ribot-Ciscar}, doi = {10.1016/j.brainres.2015.04.041}, year = {2015}, date = {2015-07-30}, journal = {Brain Research}, volume = {1615}, pages = {148–156}, abstract = {In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (−51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (−38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (−51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (−38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief. |
Di Stefano F.; Epelbaum S.; Coley N.; Cantet C.; Ousset P.J.; Hampel H.; Bakardjian H.; Lista S.; Vellas B.; Dubois B.; Andrieu S.; GuidAge study group Prediction of Alzheimer's Disease Dementia: Data from the GuidAge Prevention Trial. Article de journal Journal of Alzheimer's Disease, 48 (3), p. 793-804, 2015. @article{DiStefano2015, title = {Prediction of Alzheimer's Disease Dementia: Data from the GuidAge Prevention Trial.}, author = {Di Stefano F. and Epelbaum S. and Coley N. and Cantet C. and Ousset P.J. and Hampel H. and Bakardjian H. and Lista S. and Vellas B. and Dubois B. and Andrieu S. and GuidAge study group}, doi = {10.3233/JAD-150013}, year = {2015}, date = {2015-06-30}, journal = {Journal of Alzheimer's Disease}, volume = {48}, number = {3}, pages = {793-804}, abstract = {In therapeutic trials, it is crucial to identify Alzheimer’s disease (AD) at its prodromal stage. We assessed the accuracy of the free and cued selective reminding test (FCSRT) compared to other cognitive tests to predict AD dementia in subjects with subjective cognitive decline or mild cognitive impairment. Subjects from the placebo group of the GuidAge trial over 70 years old and without clinical signs of dementia at baseline who completed the 5-year follow-up free of dementia (n = 840) or developed AD dementia (n = 73) were included in our study. Among all the tests, the sum of the 3 free recall of the FCSRT (FCSRT-FR) and the sum of free and cued recall (FCSRT-TR) yielded the best results to predict AD dementia occurrence (all p values <0.05 for comparison of FCSRT-FR ROC and MMSE, CDRsb, and CVF ROCs). FCSRT-FR had an area under the ROC curve of 0.799 (95% CI 0.738–0.85) and the optimal cut-off was 20 (se 68.06% , sp 81.43% , PPV 23.90% , NPV 96,75%). Concerning FCSRT-TR, the AUC was 0.776 and the optimal cut-off was 42 (se 62.5% , sp 82.26% , PPV 23.20% and NPV 96.24%). This study sets the framework for implementing the FCSRT in clinical and therapeutic trials for efficient subject selection.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In therapeutic trials, it is crucial to identify Alzheimer’s disease (AD) at its prodromal stage. We assessed the accuracy of the free and cued selective reminding test (FCSRT) compared to other cognitive tests to predict AD dementia in subjects with subjective cognitive decline or mild cognitive impairment. Subjects from the placebo group of the GuidAge trial over 70 years old and without clinical signs of dementia at baseline who completed the 5-year follow-up free of dementia (n = 840) or developed AD dementia (n = 73) were included in our study. Among all the tests, the sum of the 3 free recall of the FCSRT (FCSRT-FR) and the sum of free and cued recall (FCSRT-TR) yielded the best results to predict AD dementia occurrence (all p values <0.05 for comparison of FCSRT-FR ROC and MMSE, CDRsb, and CVF ROCs). FCSRT-FR had an area under the ROC curve of 0.799 (95% CI 0.738–0.85) and the optimal cut-off was 20 (se 68.06% , sp 81.43% , PPV 23.90% , NPV 96,75%). Concerning FCSRT-TR, the AUC was 0.776 and the optimal cut-off was 42 (se 62.5% , sp 82.26% , PPV 23.20% and NPV 96.24%). This study sets the framework for implementing the FCSRT in clinical and therapeutic trials for efficient subject selection. |
Claude Touzet Sleep: the hebbian reinforcement of the local inhibitory synapses Article de journal Med. Hypotheses, 85 , p. 359-364, 2015. @article{Touzet2015, title = {Sleep: the hebbian reinforcement of the local inhibitory synapses}, author = {Claude Touzet}, editor = {Elsevier}, url = {http://www.touzet.org/Claude/Web-Fac-Claude/Publi/Medical-Hypotheses/Medical-Hypotheses_TOUZET.pdf}, doi = {doi:10.1016/j.mehy.2015.06.013}, year = {2015}, date = {2015-06-17}, journal = {Med. Hypotheses}, volume = {85}, pages = {359-364}, abstract = {Sleep is ubiquitous among the animal realm, and represents about 30% of our lives. Despite numerous efforts, the reason behind our need for sleep is still unknown. The Theory of neuronal Cognition (TnC) proposes that sleep is the period of time during which the local inhibitory synapses (in particular the cortical ones) are replenished. Indeed, as long as the active brain stays awake, hebbian learning guarantees that efficient inhibitory synapses lose their efficiency – just because they are efficient at avoiding the activation of the targeted neurons. Since hebbian learning is the only known mechanism of synapse modification, it follows that to replenish the inhibitory synapses’ efficiency, source and targeted neurons must be activated together. This is achieved by a local depolarization that may travel (wave). The period of time during which such slow waves are experienced has been named the ‘‘slow-wave sleep’’ (SWS). It is cut into several pieces by shorter periods of paradoxical sleep (REM) which activity resembles that of the awake state. Indeed, SWS – because it only allows local neural activation – decreases the excitatory long distance connections strength. To avoid losing the associations built during the awake state, these long distance activations are played again during the REM sleep. REM and SWS sleeps act together to guarantee that when the subject awakes again, his inhibitory synaptic efficiency is restored and his (excitatory) long distance associations are still there.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Sleep is ubiquitous among the animal realm, and represents about 30% of our lives. Despite numerous efforts, the reason behind our need for sleep is still unknown. The Theory of neuronal Cognition (TnC) proposes that sleep is the period of time during which the local inhibitory synapses (in particular the cortical ones) are replenished. Indeed, as long as the active brain stays awake, hebbian learning guarantees that efficient inhibitory synapses lose their efficiency – just because they are efficient at avoiding the activation of the targeted neurons. Since hebbian learning is the only known mechanism of synapse modification, it follows that to replenish the inhibitory synapses’ efficiency, source and targeted neurons must be activated together. This is achieved by a local depolarization that may travel (wave). The period of time during which such slow waves are experienced has been named the ‘‘slow-wave sleep’’ (SWS). It is cut into several pieces by shorter periods of paradoxical sleep (REM) which activity resembles that of the awake state. Indeed, SWS – because it only allows local neural activation – decreases the excitatory long distance connections strength. To avoid losing the associations built during the awake state, these long distance activations are played again during the REM sleep. REM and SWS sleeps act together to guarantee that when the subject awakes again, his inhibitory synaptic efficiency is restored and his (excitatory) long distance associations are still there. |
R. Ackerley; A. Kavounoudias The role of tactile afference in shaping motor behaviour and implications for prosthetic innovation. Neuropsychologia Article de journal Neuropsychologia, 79 , p. 192-205, 2015. @article{Ackerley2015, title = {The role of tactile afference in shaping motor behaviour and implications for prosthetic innovation. Neuropsychologia}, author = {R. Ackerley and A. Kavounoudias}, doi = {0.1016/j.neuropsychologia.2015.06.024}, year = {2015}, date = {2015-06-17}, journal = {Neuropsychologia}, volume = {79}, pages = {192-205}, abstract = {The present review focusses on how tactile somatosensory afference is encoded and processed, and how this information is interpreted and acted upon in terms of motor control. We relate the fundamental workings of the sensorimotor system to the rehabilitation of amputees using modern prosthetic interventions. Our sense of touch is central to our everyday lives, from allowing us to manipulate objects accurately to giving us a sense of self-embodiment. There are a variety of specialised cutaneous mechanoreceptive afferents, which differ in terms of type and density according to the skin site. In humans, there is a dense innervation of our hands, which is reflected in their vast over-representation in somatosensory and motor cortical areas. We review the accumulated evidence from animal and human studies about the precise interplay between the somatosensory and motor systems, which is highly integrated in many brain areas and often not separable. The glabrous hand skin provides exquisite, discriminative detail about touch, which is useful for refining movements. When these signals are disrupted, such as through injury or amputation, the consequences are considerable. The development of sensory feedback in prosthetics offers a promising avenue for the full integration of a missing body part. Real-time touch feedback from motor intentions aids in grip control and the ability to distinguish different surfaces, even introducing the possibility of pleasure in artificial touch. Thus, our knowledge from fundamental research into sensorimotor interactions should be used to develop more realistic and integrative prostheses. Copyright © 2015 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present review focusses on how tactile somatosensory afference is encoded and processed, and how this information is interpreted and acted upon in terms of motor control. We relate the fundamental workings of the sensorimotor system to the rehabilitation of amputees using modern prosthetic interventions. Our sense of touch is central to our everyday lives, from allowing us to manipulate objects accurately to giving us a sense of self-embodiment. There are a variety of specialised cutaneous mechanoreceptive afferents, which differ in terms of type and density according to the skin site. In humans, there is a dense innervation of our hands, which is reflected in their vast over-representation in somatosensory and motor cortical areas. We review the accumulated evidence from animal and human studies about the precise interplay between the somatosensory and motor systems, which is highly integrated in many brain areas and often not separable. The glabrous hand skin provides exquisite, discriminative detail about touch, which is useful for refining movements. When these signals are disrupted, such as through injury or amputation, the consequences are considerable. The development of sensory feedback in prosthetics offers a promising avenue for the full integration of a missing body part. Real-time touch feedback from motor intentions aids in grip control and the ability to distinguish different surfaces, even introducing the possibility of pleasure in artificial touch. Thus, our knowledge from fundamental research into sensorimotor interactions should be used to develop more realistic and integrative prostheses. Copyright © 2015 Elsevier Ltd. All rights reserved. |
A. Norena Revisiting the cochlear and central mechanisms of tinnitus and therapeutic approaches Article de journal Audiology Neurotology, 20 (1), 2015. @article{Norena2015b, title = {Revisiting the cochlear and central mechanisms of tinnitus and therapeutic approaches}, author = {A. Norena}, doi = {10.1159/000380749}, year = {2015}, date = {2015-05-19}, journal = {Audiology Neurotology}, volume = {20}, number = {1}, abstract = {This short review aims at revisiting some of the putative mechanisms of tinnitus. Cochlear-type tinnitus is suggested to result from aberrant activity generated before or at the cochlear nerve level. It is proposed that outer hair cells, through their role in regulating the endocochlear potential, can contribute to the enhancement of cochlear spontaneous activity. This hypothesis is attractive as it provides a possible explanation for cochlear tinnitus of different aetiologies, such as tinnitus produced by acute noise trauma, intense low-frequency sounds, middle-ear dysfunction or temporomandibular joint disorders. Other mechanisms, namely an excitatory drift in the operating point of the inner hair cells and activation of NMDA receptors, are also briefly reported. Central-type tinnitus is supposed to result from aberrant activity generated in auditory centres, i.e. in these patients, the tinnitus-related activity does not pre-exist in the cochlear nerve. A reduction in cochlear activity due to hearing loss is suggested to produce tinnitus-related plastic changes, namely cortical reorganisation, thalamic neuron hyperpolarisation, facilitation of non-auditory inputs and/or increase in central gain. These central changes can be associated with abnormal patterns of spontaneous activity in the auditory pathway, i.e. hyperactivity, hypersynchrony and/or oscillating activity. Therapeutic approaches aimed at reducing cochlear activity and/or tinnitus-related central changes are discussed. © 2015 S. Karger AG, Basel.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This short review aims at revisiting some of the putative mechanisms of tinnitus. Cochlear-type tinnitus is suggested to result from aberrant activity generated before or at the cochlear nerve level. It is proposed that outer hair cells, through their role in regulating the endocochlear potential, can contribute to the enhancement of cochlear spontaneous activity. This hypothesis is attractive as it provides a possible explanation for cochlear tinnitus of different aetiologies, such as tinnitus produced by acute noise trauma, intense low-frequency sounds, middle-ear dysfunction or temporomandibular joint disorders. Other mechanisms, namely an excitatory drift in the operating point of the inner hair cells and activation of NMDA receptors, are also briefly reported. Central-type tinnitus is supposed to result from aberrant activity generated in auditory centres, i.e. in these patients, the tinnitus-related activity does not pre-exist in the cochlear nerve. A reduction in cochlear activity due to hearing loss is suggested to produce tinnitus-related plastic changes, namely cortical reorganisation, thalamic neuron hyperpolarisation, facilitation of non-auditory inputs and/or increase in central gain. These central changes can be associated with abnormal patterns of spontaneous activity in the auditory pathway, i.e. hyperactivity, hypersynchrony and/or oscillating activity. Therapeutic approaches aimed at reducing cochlear activity and/or tinnitus-related central changes are discussed. © 2015 S. Karger AG, Basel. |
Claude Touzet The Theory of Neural Cognition Applied to Robotics Article de journal International Journal of Advanced Robotic Systems, 12 (74), p. , 2015, ISBN: . @article{Touzet2015, title = {The Theory of Neural Cognition Applied to Robotics}, author = {Claude Touzet}, editor = {In Tech}, url = {http://www.touzet.org/Claude/Web-Fac-Claude/Publi/IJARS2015/IJARS-2015-Touzet-Publi.pdf}, doi = {10.5772/60693}, isbn = { }, year = {2015}, date = {2015-04-20}, journal = {International Journal of Advanced Robotic Systems}, volume = {12}, number = {74}, pages = { }, abstract = {The Theory of neural Cognition (TnC) states that the brain does not process information, it only represents information (i.e., it is 'only' a memory). The TnC explains how a memory can become an actor pursuing various goals, and proposes explanations concerning the implementation of a large variety of cognitive abilities, such as attention, memory, language, planning, intelligence, emotions, motivation, pleasure, consciousness and personality. The explanatory power of this new framework extends further though, to tackle special psychological states such as hypnosis, the placebo effect and sleep, and brain diseases such as autism, Alzheimer’s disease and schizophrenia. The most interesting findings concern robotics: because the TnC considers the cortical column to be the key cognitive unit (instead of the neuron), it reduces the requirements for a brain implementation to only 160,000 units (instead of 86 billion). A robot exhibiting human-like cognitive abilities is therefore within our reach.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Theory of neural Cognition (TnC) states that the brain does not process information, it only represents information (i.e., it is 'only' a memory). The TnC explains how a memory can become an actor pursuing various goals, and proposes explanations concerning the implementation of a large variety of cognitive abilities, such as attention, memory, language, planning, intelligence, emotions, motivation, pleasure, consciousness and personality. The explanatory power of this new framework extends further though, to tackle special psychological states such as hypnosis, the placebo effect and sleep, and brain diseases such as autism, Alzheimer’s disease and schizophrenia. The most interesting findings concern robotics: because the TnC considers the cortical column to be the key cognitive unit (instead of the neuron), it reduces the requirements for a brain implementation to only 160,000 units (instead of 86 billion). A robot exhibiting human-like cognitive abilities is therefore within our reach. |
N. Montejo; A. J. Noreña Dynamic representation of spectral edges in guinea pig primary auditory cortex Article de journal Journal of Neurophysiology, 113 (7), p. 2998-3012, 2015. @article{Montejo2015, title = {Dynamic representation of spectral edges in guinea pig primary auditory cortex}, author = {N. Montejo and A. J. Noreña}, doi = {10.1152/jn.00785.2014}, year = {2015}, date = {2015-04-01}, journal = {Journal of Neurophysiology}, volume = {113}, number = {7}, pages = {2998-3012}, abstract = {The central representation of a given acoustic motif is thought to be strongly context dependent, i.e., to rely on the spectrotemporal past and present of the acoustic mixture in which it is embedded. The present study investigated the cortical representation of spectral edges (i.e., where stimulus energy changes abruptly over frequency) and its dependence on stimulus duration and depth of the spectral contrast in guinea pig. We devised a stimulus ensemble composed of random tone pips with or without an attenuated frequency band (AFB) of variable depth. Additionally, the multitone ensemble with AFB was interleaved with periods of silence or with multitone ensembles without AFB. We have shown that the representation of the frequencies near but outside the AFB is greatly enhanced, whereas the representation of frequencies near and inside the AFB is strongly suppressed. These cortical changes depend on the depth of the AFB: although they are maximal for the largest depth of the AFB, they are also statistically significant for depths as small as 10 dB. Finally, the cortical changes are quick, occurring within a few seconds of stimulus ensemble presentation with AFB, and are very labile, disappearing within a few seconds after the presentation without AFB. Overall, this study demonstrates that the representation of spectral edges is dynamically enhanced in the auditory centers. These central changes may have important functional implications, particularly in noisy environments where they could contribute to preserving the central representation of spectral edges. Copyright © 2015 the American Physiological Society. }, key = {artificial hearing loss; short-term synaptic plasticity; synaptic inhibition; tinnitus}, keywords = {}, pubstate = {published}, tppubtype = {article} } The central representation of a given acoustic motif is thought to be strongly context dependent, i.e., to rely on the spectrotemporal past and present of the acoustic mixture in which it is embedded. The present study investigated the cortical representation of spectral edges (i.e., where stimulus energy changes abruptly over frequency) and its dependence on stimulus duration and depth of the spectral contrast in guinea pig. We devised a stimulus ensemble composed of random tone pips with or without an attenuated frequency band (AFB) of variable depth. Additionally, the multitone ensemble with AFB was interleaved with periods of silence or with multitone ensembles without AFB. We have shown that the representation of the frequencies near but outside the AFB is greatly enhanced, whereas the representation of frequencies near and inside the AFB is strongly suppressed. These cortical changes depend on the depth of the AFB: although they are maximal for the largest depth of the AFB, they are also statistically significant for depths as small as 10 dB. Finally, the cortical changes are quick, occurring within a few seconds of stimulus ensemble presentation with AFB, and are very labile, disappearing within a few seconds after the presentation without AFB. Overall, this study demonstrates that the representation of spectral edges is dynamically enhanced in the auditory centers. These central changes may have important functional implications, particularly in noisy environments where they could contribute to preserving the central representation of spectral edges. Copyright © 2015 the American Physiological Society. |
C. T. Dinh; S. Goncalves; E. Bas; T. R. Van De Water; A. Zine Molecular regulation of auditory hair cell death and approaches to protect sensory receptor cells and/or stimulate repair following acoustic trauma Article de journal Frontiers in Cellular Neuroscience, 2015. @article{Dinh2015, title = {Molecular regulation of auditory hair cell death and approaches to protect sensory receptor cells and/or stimulate repair following acoustic trauma}, author = {C. T. Dinh and S. Goncalves and E. Bas and T. R. Van De Water and A. Zine}, doi = {10.3389/fncel.2015.00096}, year = {2015}, date = {2015-03-31}, journal = {Frontiers in Cellular Neuroscience}, abstract = {Loss of auditory sensory hair cells (HCs) is the most common cause of hearing loss. This review addresses the signaling pathways that are involved in the programmed and necrotic cell death of auditory HCs that occur in response to ototoxic and traumatic stressor events. The roles of inflammatory processes, oxidative stress, mitochondrial damage, cell death receptors, members of the mitogen-activated protein kinase (MAPK) signal pathway and pro- and anti-cell death members of the Bcl-2 family are explored. The molecular interaction of these signal pathways that initiates the loss of auditory HCs following acoustic trauma is covered and possible therapeutic interventions that may protect these sensory HCs from loss via apoptotic or non-apoptotic cell death are explored.}, key = {trauma, cochlea, auditory hair cells, apoptosis, inflammation, necrosis, otoprotection, repair}, keywords = {}, pubstate = {published}, tppubtype = {article} } Loss of auditory sensory hair cells (HCs) is the most common cause of hearing loss. This review addresses the signaling pathways that are involved in the programmed and necrotic cell death of auditory HCs that occur in response to ototoxic and traumatic stressor events. The roles of inflammatory processes, oxidative stress, mitochondrial damage, cell death receptors, members of the mitogen-activated protein kinase (MAPK) signal pathway and pro- and anti-cell death members of the Bcl-2 family are explored. The molecular interaction of these signal pathways that initiates the loss of auditory HCs following acoustic trauma is covered and possible therapeutic interventions that may protect these sensory HCs from loss via apoptotic or non-apoptotic cell death are explored. |
K. Fuminari; C. Blanchard; N. Lebar; B. Nazarian; A. Kavounoudias; P. Romaiguère Brain regions associated to a kinesthetic illusion evoked by watching a video of one's own moving hand Article de journal PLoS One, 2015. @article{Fuminari2015, title = {Brain regions associated to a kinesthetic illusion evoked by watching a video of one's own moving hand}, author = {K. Fuminari and C. Blanchard and N. Lebar and B. Nazarian and A. Kavounoudias and P. Romaiguère }, doi = {10.1371/journal.pone.0131970}, year = {2015}, date = {2015-02-12}, journal = {PLoS One}, abstract = {It is well known that kinesthetic illusions can be induced by stimulation of several sensory systems (proprioception, touch, vision…). In this study we investigated the cerebral network underlying a kinesthetic illusion induced by visual stimulation by using functional magnetic resonance imaging (fMRI) in humans. Participants were instructed to keep their hand still while watching the video of their own moving hand (Self Hand) or that of someone else's moving hand (Other Hand). In the Self Hand condition they experienced an illusory sensation that their hand was moving whereas the Other Hand condition did not induce any kinesthetic illusion. The contrast between the Self Hand and Other Hand conditions showed significant activation in the left dorsal and ventral premotor cortices, in the left Superior and Inferior Parietal lobules, at the right Occipito-Temporal junction as well as in bilateral Insula and Putamen. Most strikingly, there was no activation in the primary motor and somatosensory cortices, whilst previous studies have reported significant activation in these regions for vibration-induced kinesthetic illusions. To our knowledge, this is the first study that indicates that humans can experience kinesthetic perception without activation in the primary motor and somatosensory areas. We conclude that under some conditions watching a video of one's own moving hand could lead to activation of a network that is usually involved in processing copies of efference, thus leading to the illusory perception that the real hand is indeed moving.}, keywords = {}, pubstate = {published}, tppubtype = {article} } It is well known that kinesthetic illusions can be induced by stimulation of several sensory systems (proprioception, touch, vision…). In this study we investigated the cerebral network underlying a kinesthetic illusion induced by visual stimulation by using functional magnetic resonance imaging (fMRI) in humans. Participants were instructed to keep their hand still while watching the video of their own moving hand (Self Hand) or that of someone else's moving hand (Other Hand). In the Self Hand condition they experienced an illusory sensation that their hand was moving whereas the Other Hand condition did not induce any kinesthetic illusion. The contrast between the Self Hand and Other Hand conditions showed significant activation in the left dorsal and ventral premotor cortices, in the left Superior and Inferior Parietal lobules, at the right Occipito-Temporal junction as well as in bilateral Insula and Putamen. Most strikingly, there was no activation in the primary motor and somatosensory cortices, whilst previous studies have reported significant activation in these regions for vibration-induced kinesthetic illusions. To our knowledge, this is the first study that indicates that humans can experience kinesthetic perception without activation in the primary motor and somatosensory areas. We conclude that under some conditions watching a video of one's own moving hand could lead to activation of a network that is usually involved in processing copies of efference, thus leading to the illusory perception that the real hand is indeed moving. |
S. Aidi-Knani; L. Pezard; B. Mpari; J. Ben Hamida; J-M. Sabatier; C. Mourre; I. Regaya Correspondences between the binding characteristics of non-natural peptide, Lei-Dab7 and the distribution of SK subunits in the rat central nervous system Article de journal European Journal of Pharmacology, 752 , p. 106-111, 2015. @article{Aidi-Knani2015, title = {Correspondences between the binding characteristics of non-natural peptide, Lei-Dab7 and the distribution of SK subunits in the rat central nervous system}, author = {S. Aidi-Knani and L. Pezard and B. Mpari and J. Ben Hamida and J-M. Sabatier and C. Mourre and I. Regaya}, doi = {10.1016/j.ejphar.2015.02.011}, year = {2015}, date = {2015-02-11}, journal = {European Journal of Pharmacology}, volume = {752}, pages = {106-111}, abstract = {Small-conductance calcium-activated potassium channels (SK1-SK3 channels) are responsible for long-lasting hyperpolarization following action potential and contribute to the neuronal firing and integration signal. Two peptide toxins: apamin and Leiurotoxin 1, block this SK channels with high affinities. We generated a modified Leiurotoxin 1 (Lei-Dab7) that inhibits SK2 channels with a high selectivity. Competitive binding of radio-iodinated apamin to different rat brain structures, in the presence of native apamin and Lei-Dab7, has shown that dissociation constants differ by a factor of 1000 and thus demonstrated that ligand affinity is as important as ligand selectivity for a specific receptor. However, the lack of ligands discriminating between SK channel subunits is impeding the understanding of the role of each heteromeric SK channel type in different tissues. Our study aims to better understand the molecular combinations of SK channels and their association with specific functional implications. On this purpose, a clustering technique allows us to identify five groups of brain structures reflecting singular profiles of affinity and selectivity of Lei-Dab7 in comparison with apamin. The analysis of correspondences between Lei-Dab7 binding and distribution of SK subunits in these groups of brain structures suggests that functional heteromeric SK channels are involved in specific information processes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Small-conductance calcium-activated potassium channels (SK1-SK3 channels) are responsible for long-lasting hyperpolarization following action potential and contribute to the neuronal firing and integration signal. Two peptide toxins: apamin and Leiurotoxin 1, block this SK channels with high affinities. We generated a modified Leiurotoxin 1 (Lei-Dab7) that inhibits SK2 channels with a high selectivity. Competitive binding of radio-iodinated apamin to different rat brain structures, in the presence of native apamin and Lei-Dab7, has shown that dissociation constants differ by a factor of 1000 and thus demonstrated that ligand affinity is as important as ligand selectivity for a specific receptor. However, the lack of ligands discriminating between SK channel subunits is impeding the understanding of the role of each heteromeric SK channel type in different tissues. Our study aims to better understand the molecular combinations of SK channels and their association with specific functional implications. On this purpose, a clustering technique allows us to identify five groups of brain structures reflecting singular profiles of affinity and selectivity of Lei-Dab7 in comparison with apamin. The analysis of correspondences between Lei-Dab7 binding and distribution of SK subunits in these groups of brain structures suggests that functional heteromeric SK channels are involved in specific information processes. |
C. Brun; M. Metral; M. Chancel; A. Kavounoudias; M. Luyat; M. Guerraza PASSIVE OR SIMULATED DISPLACEMENT OF ONE ARM (BUT NOT ITS MIRROR REFLECTION) MODULATES THE INVOLUNTARY MOTOR BEHAVIOR OF THE OTHER ARM Article de journal Neuroscience, 285 , p. 343-355, 2015. @article{Brun2015, title = {PASSIVE OR SIMULATED DISPLACEMENT OF ONE ARM (BUT NOT ITS MIRROR REFLECTION) MODULATES THE INVOLUNTARY MOTOR BEHAVIOR OF THE OTHER ARM}, author = {C. Brun and M. Metral and M. Chancel and A. Kavounoudias and M. Luyat and M. Guerraza}, doi = {10.1016/j.neuroscience.2014.11.036}, year = {2015}, date = {2015-01-29}, journal = {Neuroscience}, volume = {285}, pages = {343-355}, abstract = {Recent studies of both healthy and patient populations have cast doubt on the mirror paradigm’s beneficial effect on motor behavior. Indeed, the voluntary arm displacement that accompanies reflection in the mirror may be the determining factor in terms of the motor behavior of the contralateral arm. The objective of the present study was to assess the respective effects of mirror reflection and arm displacement (whether real or simulated) on involuntary motor behavior of the contralateral arm following sustained, isometric contraction (Kohnstamm phenomenon). Our results revealed that (i) passive displacement of one arm (displacement of the left arm via a motorized manipulandum moving at 4°/s) influenced the velocity of the Kohnstamm phenomenon (forearm flexion occurring shortly after the cessation of muscle contraction) in the contralateral arm and (ii) mirror vision had no effect. Indeed, the velocity of the Kohnstamm phenomenon tended to be adjusted to match the velocity of the passive displacement of the other arm. In a second experiment, arm displacement was simulated by vibrating the triceps at 25, 50 or 75 Hz. Results showed that the velocity of the Kohnstamm phenomenon in one arm increased with the vibration frequency applied to the other arm. Our results revealed the occurrence of bimanual coupling because involuntary displacement of one arm was regulated by muscle-related information generated by the actual or simulated displacement of the other arm. In line with the literature data on voluntary motor behavior, our study failed to evidence an additional impact of mirror vision on involuntary motor behavior.}, key = {mirror paradigm; bimanual coupling; Kohnstamm phenomenon; muscular afferents}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recent studies of both healthy and patient populations have cast doubt on the mirror paradigm’s beneficial effect on motor behavior. Indeed, the voluntary arm displacement that accompanies reflection in the mirror may be the determining factor in terms of the motor behavior of the contralateral arm. The objective of the present study was to assess the respective effects of mirror reflection and arm displacement (whether real or simulated) on involuntary motor behavior of the contralateral arm following sustained, isometric contraction (Kohnstamm phenomenon). Our results revealed that (i) passive displacement of one arm (displacement of the left arm via a motorized manipulandum moving at 4°/s) influenced the velocity of the Kohnstamm phenomenon (forearm flexion occurring shortly after the cessation of muscle contraction) in the contralateral arm and (ii) mirror vision had no effect. Indeed, the velocity of the Kohnstamm phenomenon tended to be adjusted to match the velocity of the passive displacement of the other arm. In a second experiment, arm displacement was simulated by vibrating the triceps at 25, 50 or 75 Hz. Results showed that the velocity of the Kohnstamm phenomenon in one arm increased with the vibration frequency applied to the other arm. Our results revealed the occurrence of bimanual coupling because involuntary displacement of one arm was regulated by muscle-related information generated by the actual or simulated displacement of the other arm. In line with the literature data on voluntary motor behavior, our study failed to evidence an additional impact of mirror vision on involuntary motor behavior. |
M. Metral; M. Chancel; C. Brun; M. Luyat; A. Kavounoudias; M. Guerraz Kinaesthetic mirror illusion and spatial congruence Article de journal Experimental Brain Research, 233 (5), p. 1463-1470, 2015. @article{Metral2015, title = {Kinaesthetic mirror illusion and spatial congruence}, author = {M. Metral and M. Chancel and C. Brun and M. Luyat and A. Kavounoudias and M. Guerraz }, doi = {10.1007/s00221-015-4220-1}, year = {2015}, date = {2015-01-28}, journal = {Experimental Brain Research}, volume = {233}, number = {5}, pages = {1463-1470}, abstract = {Position sense and kinaesthesia are mainly derived from the integration of somaesthetic and visual afferents to form a single, coherent percept. However, visual information related to the body can play a dominant role in these perceptual processes in some circumstances, and notably in the mirror paradigm. The objective of the present study was to determine whether or not the kinaesthetic illusions experienced in the mirror paradigm obey one of the key rules of multisensory integration: spatial congruence. In the experiment, the participant’s left arm (the image of which was reflected in a mirror) was either passively flexed/extended with a motorized manipulandum (to induce a kinaesthetic illusion in the right arm) or remained static. The right (unseen) arm remained static but was positioned parallel to the left arm’s starting position or placed in extension (from 15° to 90°, in steps of 15°), relative to the left arm’s flexed starting position. The results revealed that the frequency of the illusion decreased only slightly as the incongruence prior to movement onset between the reflected left arm and the hidden right arm grew and remained quite high even in the most incongruent settings. However, the greater the incongruence between the visually and somaesthetically specified positions of the right forearm (from 15° to 90°), the later the onset and the lower the perceived speed of the kinaesthetic illusion. Although vision dominates perception in a context of visuoproprioceptive conflict (as in the mirror paradigm), our results show that the relative weightings allocated to proprioceptive and visual signals vary according to the degree of spatial incongruence prior to movement onset.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Position sense and kinaesthesia are mainly derived from the integration of somaesthetic and visual afferents to form a single, coherent percept. However, visual information related to the body can play a dominant role in these perceptual processes in some circumstances, and notably in the mirror paradigm. The objective of the present study was to determine whether or not the kinaesthetic illusions experienced in the mirror paradigm obey one of the key rules of multisensory integration: spatial congruence. In the experiment, the participant’s left arm (the image of which was reflected in a mirror) was either passively flexed/extended with a motorized manipulandum (to induce a kinaesthetic illusion in the right arm) or remained static. The right (unseen) arm remained static but was positioned parallel to the left arm’s starting position or placed in extension (from 15° to 90°, in steps of 15°), relative to the left arm’s flexed starting position. The results revealed that the frequency of the illusion decreased only slightly as the incongruence prior to movement onset between the reflected left arm and the hidden right arm grew and remained quite high even in the most incongruent settings. However, the greater the incongruence between the visually and somaesthetically specified positions of the right forearm (from 15° to 90°), the later the onset and the lower the perceived speed of the kinaesthetic illusion. Although vision dominates perception in a context of visuoproprioceptive conflict (as in the mirror paradigm), our results show that the relative weightings allocated to proprioceptive and visual signals vary according to the degree of spatial incongruence prior to movement onset. |
G. Rammes; A. Gravius; M. Ruitenberg; N. Wegener; C. Chambon; K. Sroka-saidi; R. Jeggo; L. Staniaszek; D. Spanswick; E. O'hare; P. Palmer; E. Kim; W. Bywalez; V. Egger; C. G. Parsons Neuropharmacology, 92 , p. 170-82, 2015, (Mots clefs: Aggregation; Alternating lever cyclic ratio schedule (ALCR); Alzheimer's disease; Beta-amyloid; Calcium imaging; Dendritic spines; In vitro; In vivo; Long term potentiation (LTP); Novel object recognition (NOR); Oligomers; Pharmacokinetics; Synaptotoxicity). @article{Rammes2015, title = {MRZ-99030 - a novel modulator of Abeta aggregation: II - reversal of Abeta oligomer-induced deficits in long-term potentiation (LTP) and cognitive performance in rats and mice.}, author = {G. Rammes and A. Gravius and M. Ruitenberg and N. Wegener and C. Chambon and K. Sroka-saidi and R. Jeggo and L. Staniaszek and D. Spanswick and E. O'hare and P. Palmer and E. Kim and W. Bywalez and V. Egger and C. G. Parsons}, doi = {10.1016}, year = {2015}, date = {2015-01-28}, journal = {Neuropharmacology}, volume = {92}, pages = {170-82}, abstract = {β-amyloid1-42 (Aβ1-42) is a major endogenous pathogen underlying the aetiology of Alzheimer's disease (AD). Recent evidence indicates that soluble Aβ oligomers, rather than plaques, are the major cause of synaptic dysfunction and neurodegeneration. Small molecules that suppress Aβ aggregation, reduce oligomer stability or promote off-pathway non-toxic oligomerization represent a promising alternative strategy for neuroprotection in AD. MRZ-99030 was recently identified as a dipeptide that modulates Aβ1-42 aggregation by triggering a non-amyloidogenic aggregation pathway, thereby reducing the amount of intermediate toxic soluble oligomeric Aβ species. The present study evaluated the relevance of these promising results with MRZ-99030 under pathophysiological conditions i.e. against the synaptotoxic effects of Aβ oligomers on hippocampal long term potentiation (LTP) and two different memory tasks. Aβ1-42 interferes with the glutamatergic system and with neuronal Ca(2+) signalling and abolishes the induction of LTP. Here we demonstrate that MRZ-99030 (100-500 nM) at a 10:1 stoichiometric excess to Aβ clearly reversed the synaptotoxic effects of Aβ1-42 oligomers on CA1-LTP in murine hippocampal slices. Co-application of MRZ-99030 also prevented the two-fold increase in resting Ca(2+) levels in pyramidal neuron dendrites and spines triggered by Aβ1-42 oligomers. In anaesthetized rats, pre-administration of MRZ-99030 (50 mg/kg s.c.) protected against deficits in hippocampal LTP following i.c.v. injection of oligomeric Aβ1-42. Furthermore, similar treatment significantly ameliorated cognitive deficits in an object recognition task and under an alternating lever cyclic ratio schedule after the i.c.v. application of Aβ1-42 and 7PA2 conditioned medium, respectively. Altogether, these results demonstrate the potential therapeutic benefit of MRZ-99030 in AD.}, note = {Mots clefs: Aggregation; Alternating lever cyclic ratio schedule (ALCR); Alzheimer's disease; Beta-amyloid; Calcium imaging; Dendritic spines; In vitro; In vivo; Long term potentiation (LTP); Novel object recognition (NOR); Oligomers; Pharmacokinetics; Synaptotoxicity}, keywords = {}, pubstate = {published}, tppubtype = {article} } β-amyloid1-42 (Aβ1-42) is a major endogenous pathogen underlying the aetiology of Alzheimer's disease (AD). Recent evidence indicates that soluble Aβ oligomers, rather than plaques, are the major cause of synaptic dysfunction and neurodegeneration. Small molecules that suppress Aβ aggregation, reduce oligomer stability or promote off-pathway non-toxic oligomerization represent a promising alternative strategy for neuroprotection in AD. MRZ-99030 was recently identified as a dipeptide that modulates Aβ1-42 aggregation by triggering a non-amyloidogenic aggregation pathway, thereby reducing the amount of intermediate toxic soluble oligomeric Aβ species. The present study evaluated the relevance of these promising results with MRZ-99030 under pathophysiological conditions i.e. against the synaptotoxic effects of Aβ oligomers on hippocampal long term potentiation (LTP) and two different memory tasks. Aβ1-42 interferes with the glutamatergic system and with neuronal Ca(2+) signalling and abolishes the induction of LTP. Here we demonstrate that MRZ-99030 (100-500 nM) at a 10:1 stoichiometric excess to Aβ clearly reversed the synaptotoxic effects of Aβ1-42 oligomers on CA1-LTP in murine hippocampal slices. Co-application of MRZ-99030 also prevented the two-fold increase in resting Ca(2+) levels in pyramidal neuron dendrites and spines triggered by Aβ1-42 oligomers. In anaesthetized rats, pre-administration of MRZ-99030 (50 mg/kg s.c.) protected against deficits in hippocampal LTP following i.c.v. injection of oligomeric Aβ1-42. Furthermore, similar treatment significantly ameliorated cognitive deficits in an object recognition task and under an alternating lever cyclic ratio schedule after the i.c.v. application of Aβ1-42 and 7PA2 conditioned medium, respectively. Altogether, these results demonstrate the potential therapeutic benefit of MRZ-99030 in AD. |
Krell-Roesch J.; Woodruff B. K.; Acosta J. I.; Locke D.E.; Hentz J. G.; Stonnington C. M.; Stokin G. B.; Nagle C.; Michel B. F.; Sambuchi N.; Caselli R. J.; Geda Y. E. APOE ε4 Genotype and the Risk for Subjective Cognitive Impairment in Elderly Persons Article de journal The Journal of Neuropsychiatry, 27 (4), p. 322-325, 2015. @article{KrellRoesch2015, title = {APOE ε4 Genotype and the Risk for Subjective Cognitive Impairment in Elderly Persons}, author = {Krell-Roesch J. and Woodruff B. K. and Acosta J. I. and Locke D.E. and Hentz J. G. and Stonnington C. M. and Stokin G. B. and Nagle C. and Michel B. F. and Sambuchi N. and Caselli R. J. and Geda Y. E.}, doi = {10.1176/appi.neuropsych.14100268}, year = {2015}, date = {2015-01-15}, journal = {The Journal of Neuropsychiatry}, volume = {27}, number = {4}, pages = {322-325}, abstract = {The authors compared the risk for subjective cognitive impairment (SCI) between carriers of the apolipoprotein E ε4 (APOE ε4) allele (cases) and APOE ε4 noncarriers (controls). SCI was assessed by a validated self-reported questionnaire. The authors used multivariable logistic regression analyses to compute odds ratios and 95% confidence intervals adjusted for age, sex, education, and marital status. Data were available on 114 participants (83 women; 47 APOE ε4 carriers; mean age, 69 years). The risk for SCI was significantly higher among cases than controls, particularly for those 70 years of age and older. These findings should be considered preliminary until confirmed by a prospective cohort study.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The authors compared the risk for subjective cognitive impairment (SCI) between carriers of the apolipoprotein E ε4 (APOE ε4) allele (cases) and APOE ε4 noncarriers (controls). SCI was assessed by a validated self-reported questionnaire. The authors used multivariable logistic regression analyses to compute odds ratios and 95% confidence intervals adjusted for age, sex, education, and marital status. Data were available on 114 participants (83 women; 47 APOE ε4 carriers; mean age, 69 years). The risk for SCI was significantly higher among cases than controls, particularly for those 70 years of age and older. These findings should be considered preliminary until confirmed by a prospective cohort study. |
C. Lopez Making sense of the body: the role of vestibular signals Article de journal Multisensory Research, 28 (5-6), p. 525 – 557, 2015. @article{Lopez2015, title = {Making sense of the body: the role of vestibular signals}, author = {C. Lopez}, doi = {10.1163/22134808-00002490}, year = {2015}, date = {2015-01-01}, journal = {Multisensory Research}, volume = {28}, number = {5-6}, pages = {525 – 557}, abstract = {The role of the vestibular system in posture and eye movement control has been extensively described. By contrast, how vestibular signals contribute to bodily perceptions is a more recent research area in the field of cognitive neuroscience. In the present review article, I will summarize recent findings showing that vestibular signals play a crucial role in making sense of the body. First, data will be presented showing that vestibular signals contribute to bodily perceptions ranging from low-level bodily perceptions, such as touch, pain, and the processing of the body’s metric properties, to higher level bodily perceptions, such as the sense of owning a body, the sense of being located within this body (embodiment), and the anchoring of the visuo-spatial perspective to this body. In the second part of the review article, I will show that vestibular information seems to be crucially involved in the visual perception of biological motion and in the visual perception of human body structure. Reciprocally, observing human bodies in motion influences vestibular self-motion perception, presumably due to sensorimotor resonance between the self and others. I will argue that recent advances in the mapping of the human vestibular cortex afford neuroscientific models of the vestibular contributions to human bodily self-consciousness.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The role of the vestibular system in posture and eye movement control has been extensively described. By contrast, how vestibular signals contribute to bodily perceptions is a more recent research area in the field of cognitive neuroscience. In the present review article, I will summarize recent findings showing that vestibular signals play a crucial role in making sense of the body. First, data will be presented showing that vestibular signals contribute to bodily perceptions ranging from low-level bodily perceptions, such as touch, pain, and the processing of the body’s metric properties, to higher level bodily perceptions, such as the sense of owning a body, the sense of being located within this body (embodiment), and the anchoring of the visuo-spatial perspective to this body. In the second part of the review article, I will show that vestibular information seems to be crucially involved in the visual perception of biological motion and in the visual perception of human body structure. Reciprocally, observing human bodies in motion influences vestibular self-motion perception, presumably due to sensorimotor resonance between the self and others. I will argue that recent advances in the mapping of the human vestibular cortex afford neuroscientific models of the vestibular contributions to human bodily self-consciousness. |
B. F. Michel; H. Becker; P. Bensa Démences avec atteinte de la substance blanche par trouble du métabolisme lipidique Book Chapter Démences, p. 473-483, 2015. @inbook{Michel2015, title = {Démences avec atteinte de la substance blanche par trouble du métabolisme lipidique}, author = {B. F. Michel and H. Becker and P. Bensa}, year = {2015}, date = {2015-01-01}, booktitle = {Démences}, pages = {473-483}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } |
A. J. Noreña; W. H. Mulders; D. Robertson Suppression of putative tinnitus-related activity by extra-cochlear electrical stimulation Article de journal Journal of Neurophysiology, 113 (1), p. 132-143, 2015. @article{Norena2015, title = {Suppression of putative tinnitus-related activity by extra-cochlear electrical stimulation}, author = {A. J. Noreña and W. H. Mulders and D. Robertson}, doi = {10.1152/jn.00580.2014}, year = {2015}, date = {2015-01-01}, journal = {Journal of Neurophysiology}, volume = {113}, number = {1}, pages = {132-143}, abstract = {Studies on animals have shown that noise-induced hearing loss is followed by an increase of spontaneous firing at several stages of the central auditory system. This central hyperactivity has been suggested to underpin the perception of tinnitus. It was shown that decreasing cochlear activity can abolish the noise-induced central hyperactivity. This latter result further suggests that an approach consisting of reducing cochlear activity may provide a therapeutic avenue for tinnitus. In this context, extra-cochlear electric stimulation (ECES) may be a good candidate to modulate cochlear activity and suppress tinnitus. Indeed, it has been shown that a positive current applied at the round window reduces cochlear nerve activity and can suppress tinnitus reliably in tinnitus subjects. The present study investigates whether ECES with a positive current can abolish the noise-induced central hyperactivity, i.e., the putative tinnitus-related activity. Spontaneous and stimulus-evoked neural activity before, during and after ECES was assessed from single-unit recordings in the inferior colliculus of anesthetized guinea pigs. We found that ECES with positive current significantly decreases the spontaneous firing rate of neurons with high characteristic frequencies, whereas negative current produces the opposite effect. The effects of the ECES are absent or even reversed for neurons with low characteristic frequencies. Importantly, ECES with positive current had only a marginal effect on thresholds and tone-induced activity of collicular neurons, suggesting that the main action of positive current is to modulate the spontaneous firing. Overall, cochlear electrical stimulation may be a viable approach for suppressing some forms of (peripheral-dependent) tinnitus. Copyright © 2015 the American Physiological Society. }, key = {auditory perception; cochlear nerve; hearing loss; noise trauma; plasticity; spontaneous activity}, keywords = {}, pubstate = {published}, tppubtype = {article} } Studies on animals have shown that noise-induced hearing loss is followed by an increase of spontaneous firing at several stages of the central auditory system. This central hyperactivity has been suggested to underpin the perception of tinnitus. It was shown that decreasing cochlear activity can abolish the noise-induced central hyperactivity. This latter result further suggests that an approach consisting of reducing cochlear activity may provide a therapeutic avenue for tinnitus. In this context, extra-cochlear electric stimulation (ECES) may be a good candidate to modulate cochlear activity and suppress tinnitus. Indeed, it has been shown that a positive current applied at the round window reduces cochlear nerve activity and can suppress tinnitus reliably in tinnitus subjects. The present study investigates whether ECES with a positive current can abolish the noise-induced central hyperactivity, i.e., the putative tinnitus-related activity. Spontaneous and stimulus-evoked neural activity before, during and after ECES was assessed from single-unit recordings in the inferior colliculus of anesthetized guinea pigs. We found that ECES with positive current significantly decreases the spontaneous firing rate of neurons with high characteristic frequencies, whereas negative current produces the opposite effect. The effects of the ECES are absent or even reversed for neurons with low characteristic frequencies. Importantly, ECES with positive current had only a marginal effect on thresholds and tone-induced activity of collicular neurons, suggesting that the main action of positive current is to modulate the spontaneous firing. Overall, cochlear electrical stimulation may be a viable approach for suppressing some forms of (peripheral-dependent) tinnitus. Copyright © 2015 the American Physiological Society. |