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Since a long time, studies have shown that the perception of nonnative phonological contrasts is improved after a short period of auditory training and retained over a long period of time after the end of training. However, the role of sleep in the consolidation of this type learning remains debated. In the present study, we investigated the role of post-training sleep in the consolidation of new phonological categories. Adult French-speakers were trained to identify two synthetic speech variants of the syllable /də/ during two 1-h training sessions. The 12-h interval between the two sessions included either a sleep (8 pm to 8 am +or- 1h) or a wake (8 am to 8 pm +or- 1 h) period. Results showed that identification dramatically improved over the first training session in both groups, and then slightly decreased over the 12-h offline interval to remain above chance levels. The analysis of reaction times (RT) showed slowed down responses after sleep as compared to wakefulness, suggesting higher attention devoted to the novel phonological stimulus. Notwithstanding, our results essentially suggest that post-training sleep does not benefit more than wakefulness to the consolidation of new phonological categories.

Background: Electroencephalography (EEG) and magnetoencephalography (MEG) are neurophysiological methods used to investigate noninvasively the spatial, temporal, and spectral dynamics of human brain functions. Objectives: This article reviews data on the use of EEG and MEG for presurgical functional brain mapping in patients with refractory focal epilepsy. The focus is on the localization of the primary sensorimotor (SM1) cortex as well as the verbal language and episodic memory functions. Material and methods: The English literature was reviewed based on a PubMed search. Relevant references in the selected papers were also included. Results: Presurgical MEG functional localization of the SM1 cortex generally overlaps with intracranial mapping. MEG allows for determination of hemispheric verbal (receptive and expressive) language dominance in neurosurgical patients with a high degree of concordance with the intracarotid amobarbital test. MEG represents an interesting technique for assessing postoperative memory outcome in patients with mesial temporal lobe epilepsy. Very few studies have evaluated the yield of EEG in these three clinical indications. High-density EEG might be a promising technique that needs further validation. Conclusion: MEG is a validated and robust technique for noninvasive functional mapping of the SM1 cortex and verbal language hemispheric dominance in patients with refractory focal epilepsy. Current data also suggest that MEG is a promising technique for assessing the hemispheric dominance of memory function. Further studies are needed to assess the clinical added value of high-density EEG in these clinical indications., SCOPUS: re.j, info:eu-repo/semantics/published

BACKGROUND: Mounting evidence suggests that autism is a network disorder, characterized by atypical brain connectivity, especially in the context of high level cognitive processes such as working memory (WM). Accordingly, atypical WM processes have been related to the social and cognitive deficits observed in children with autism spectrum disorder (ASD). METHODS: We used magnetoencephalography (MEG) to investigate connectivity differences during a high memory load (2‐back) WM task between 17 children with ASD and 20 age‐, sex‐, and IQ‐matched controls. RESULTS: We identified reduced inter‐regional alpha‐band (9‐15 Hz) phase synchronization in children with ASD during the WM task. Reduced WM‐related brain synchronization encompassed fronto‐temporal networks (ps

Learning and memory consolidation processes in children and adults: aneurophysiological and neuropsychological investigation.Sleep is a complex and active state of the brain, associated with essential functional changes[1]. Accumulated evidence in the adult population indicates that sleep participates in theconsolidation of declarative (i.e. memory for facts and episodes) and procedural (i.e. skillsand habits) memory, allowing novel information to be integrated for the long term in cerebralnetworks [2]. Whether sleep supports memory consolidation in children likewise and to thesame extent than in adults remains disputed. In this framework, I have developedexperiments aimed at investigating sleep-dependent consolidation processes both in childrenand adults, using behavioral and neurophysiological techniques (magneto-encephalography[MEG]; electro-encephalography [EEG]; functional magnetic resonance imaging [fMRI]). Tosum up, researches conducted during my PhD thesis have contributed to start unravelingneurophysiological mechanisms participating in sleep-dependent consolidation processes.On the one hand, I report that despite a lack of detectable behavioral differences, posttrainingsleep plays a role in reshaping the cerebral networks subtending implicit motorsequence learning in adults [3]. I also showed using a motor adaptation task [4] that sleepcontributes to the consolidation of procedural memory in children [5]. On the other hand, Ihave evidenced neuromagnetic correlates of learning novel semantic representations inchildren [6-7], and is currently finalizing the analysis of the effect of a post-training nap on theconsolidation of these representations. Finally, I showed in epileptic children that interictalepileptic discharges (IED) during sleep impairs declarative memory consolidation processes[8-9], and that this phenomenon is reversible upon pharmacological treatment suppressingIED. Altogether, these findings advocate the need to explore further memory consolidationand its neurophysiological basis in children, both healthy and suffering from various brainpathologies [10].[1] Urbain C. Peigneux, P. & Schmitz R. Sleep and the Brain. (to appear). In The Oxford Handbook ofSleep and Sleep Disorders. C. M. Morin and C. A. Espie (Eds.). Oxford University Press, Oxford, NY.[2] Peigneux P. Schmitz R. & Urbain C. Sleep and Forgetting. In Forgetting. S. Della Sala (Ed.).Psychology Press, Hove, UK. 2010. (pp. 165-184).[3] Urbain C. Schmitz R. Schmidt C. Cleeremans A. Van Bogaert P. Maquet P. and Peigneux P.(submitted). Neuroanatomical Sleep-Dependent Processing in the Probabilistic Serial Reaction TimeTask.[4] Huber, R. Ghilardi, M.F. Massimini, M. And Tononi, G. Local sleep and learning. Nature, 2004,430, 78-84.[5] Urbain C. Houyoux E. Albouy G. Peigneux P. (in preparation). Sleep-dependent consolidation ofprocedural learning in children.[6] Urbain C. Schmitz R. Op De Beeck M. Bourguignon M. Galer S. X. De Tiège, Van Bogaert P.and Peigneux P. (in preparation). How learning new meanings about novel objects modulates cerebralactivity in children: A MEG Study.[7] Urbain C. Schmitz R. Bourguignon M. Op De Beeck M. Galer S, De Tiège X. Van Bogaert P.Peigneux P. (2011). Learning and Fast-Mapping Meanings to Novel Object in Children: A MEG Study.17th Annual Meeting of the Organization for Human Brain Mapping [HBM], 26-30 June 2011, QuébecCity, Canada[8] Urbain C. et al. Is sleep-related consolidation impaired in focal idiopathic epilepsies of childhood?A pilot study, Epilepsy and Behavior, 2011, 22(2), 380-384.[9] Van Bogaert P. Urbain C. Galer S. Ligot N. Peigneux P. and De Tiège X. Impact of focalinterictal epileptiform discharges on behaviour and cognition in children. NeurophysiologieClinique/Clinical Neurophysiology, 2012, 42(1–2), 53-58., Doctorat en Sciences Psychologiques et de l'éducation, info:eu-repo/semantics/nonPublished