Learning and memory consolidation processes in children and adults: a neurophysiological and neuropsychological investigation

neurophysiological 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 the

consolidation of declarative (i.e., memory for facts and episodes) and procedural (i.e. skills

and habits) memory, allowing novel information to be integrated for the long term in cerebral

networks [2]. Whether sleep supports memory consolidation in children likewise and to the

same extent than in adults remains disputed. In this framework, I have developed

experiments aimed at investigating sleep-dependent consolidation processes both in children

and adults, using behavioral and neurophysiological techniques (magneto-encephalography

[MEG]; electro-encephalography [EEG]; functional magnetic resonance imaging [fMRI]). To

sum up, researches conducted during my PhD thesis have contributed to start unraveling

neurophysiological mechanisms participating in sleep-dependent consolidation processes.

On the one hand, I report that despite a lack of detectable behavioral differences, posttraining

sleep plays a role in reshaping the cerebral networks subtending implicit motor

sequence learning in adults [3]. I also showed using a motor adaptation task [4] that sleep

contributes to the consolidation of procedural memory in children [5]. On the other hand, I

have evidenced neuromagnetic correlates of learning novel semantic representations in

children [6-7], and is currently finalizing the analysis of the effect of a post-training nap on the

consolidation of these representations. Finally, I showed in epileptic children that interictal

epileptic discharges (IED) during sleep impairs declarative memory consolidation processes

[8-9], and that this phenomenon is reversible upon pharmacological treatment suppressing

IED. Altogether, these findings advocate the need to explore further memory consolidation

and its neurophysiological basis in children, both healthy and suffering from various brain

pathologies [10].

[1] Urbain C., Peigneux, P., & Schmitz R. Sleep and the Brain. (to appear). In The Oxford Handbook of

Sleep 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 Time

Task.

[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 of

procedural 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 cerebral

activity 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, Québec

City, 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 focal

interictal epileptiform discharges on behaviour and cognition in children. Neurophysiologie

Clinique/Clinical Neurophysiology, 2012, 42(1–2), 53-58.