References of "Barakat, M"
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See detailSleep slow wave changes during the middle years of life
Carrier, J.; Viens, I.; Poirier, G. et al

in European Journal of Neuroscience (2011), 33(4), 758-66

Slow waves (SW; < 4 Hz and > 75 muV) during non-rapid eye movement (NREM) sleep in humans are characterized by hyperpolarization [surface electroencephalogram (EEG) SW negative phase], during which ... [more ▼]

Slow waves (SW; < 4 Hz and > 75 muV) during non-rapid eye movement (NREM) sleep in humans are characterized by hyperpolarization [surface electroencephalogram (EEG) SW negative phase], during which cortical neurons are silent, and depolarization (surface EEG positive phase), during which the cortical neurons fire intensively. We assessed the effects of age, sex and topography on the dynamics of SW characteristics in a large population (n = 87) of healthy young (23.3 +/- 2.4 years) and middle-aged (51.9 +/- 4.6 years) volunteers. Older subjects showed lower SW density and amplitude than young subjects. Age-related lower SW density in men was especially marked in prefrontal/frontal brain areas, where they originate more frequently. Older subjects also showed longer SW positive and negative phase durations. These last results indicate that, in young subjects, cortical neurons would synchronously enter the SW hyperpolarization and depolarization phases, whereas this process would take longer in older subjects, leading to lower slope and longer SW positive and negative phases. Importantly, after controlling for SW amplitude, middle-aged subjects still showed lower slope than young subjects in prefrontal, frontal, parietal and occipital derivations. Age-related effects on SW density, frequency and positive phase duration were more prominent at the beginning of the night, when homeostatic sleep pressure is at its highest. Age-related SW changes may be associated with changes in synaptic density and white matter integrity and may underlie greater sleep fragmentation and difficulty in recuperating and maintaining sleep under challenges in older subjects. [less ▲]

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See detailFast and slow spindle involvement in the consolidation of a new motor sequence
Barakat, M.; Doyon, J.; Debas, K. et al

in Behav Brain Res (2011), 217(1), 117-21

This study aimed to determine the distinct contribution of slow (11-13 Hz) and fast (13-15 Hz) spindles in the consolidation process of a motor sequence learning task (MSL). Young subjects (n = 12) were ... [more ▼]

This study aimed to determine the distinct contribution of slow (11-13 Hz) and fast (13-15 Hz) spindles in the consolidation process of a motor sequence learning task (MSL). Young subjects (n = 12) were trained on both a finger MSL task and a control (CTRL) condition, which were administered one week apart in a counterbalanced order. Subjects were asked to practice the MSL or CTRL task in the evening (approximately 9:00 p.m.) and their performance was retested on the same task 12h later (approximately 9:00 a.m.). Polysomnographic (PSG) recordings were performed during the night following training on either task, and an automatic algorithm was used to detect fast and slow spindles and to quantify their characteristics (i.e., density, amplitude, and duration). Statistical analyses revealed higher fast (but not slow) spindle density after training on the MSL than after practice of the CTRL task. The increase in fast spindle density on the MSL task correlated positively with overnight performance gains on the MSL task and with difference in performance gain between the MSL and CTRL tasks. Together, these results suggest that fast sleep spindles help activate the cerebral network involved in overnight MSL consolidation, while slow spindles do not appear to play a role in this mnemonic process. [less ▲]

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See detailNREM slow wave oscillation rebound after sleep deprivation : effect of aging
Lafortune, M; Viens, I; Poirier, G et al

Poster (2010, June)

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See detailBrain plasticity related to the consolidation of motor sequence learning and motor adaptation
Debas, K.; Carrier, J.; Orban, Patricia ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2010), 107(41), 17839-44

This study aimed to investigate, through functional MRI (fMRI), the neuronal substrates associated with the consolidation process of two motor skills: motor sequence learning (MSL) and motor adaptation ... [more ▼]

This study aimed to investigate, through functional MRI (fMRI), the neuronal substrates associated with the consolidation process of two motor skills: motor sequence learning (MSL) and motor adaptation (MA). Four groups of young healthy individuals were assigned to either (i) a night/sleep condition, in which they were scanned while practicing a finger sequence learning task or an eight-target adaptation pointing task in the evening (test) and were scanned again 12 h later in the morning (retest) or (ii) a day/awake condition, in which they were scanned on the MSL or the MA tasks in the morning and were rescanned 12 h later in the evening. As expected and consistent with the behavioral results, the functional data revealed increased test-retest changes of activity in the striatum for the night/sleep group compared with the day/awake group in the MSL task. By contrast, the results of the MA task did not show any difference in test-retest activity between the night/sleep and day/awake groups. When the two MA task groups were combined, however, increased test-retest activity was found in lobule VI of the cerebellar cortex. Together, these findings highlight the presence of both functional and structural dissociations reflecting the off-line consolidation processes of MSL and MA. They suggest that MSL consolidation is sleep dependent and reflected by a differential increase of neural activity within the corticostriatal system, whereas MA consolidation necessitates either a period of daytime or sleep and is associated with increased neuronal activity within the corticocerebellar system. [less ▲]

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See detailSleep spindles and neural activity changes in the cortico-striatal system underlie motor sequence consolidation
Barakat, M; Carrier, J; Debas, K et al

in NeuroImage (2010), 51(Suppl. 1),

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See detailAge related change in NREM slow oscillations rebound after sleep deprivation
Lafortune, M; Viens, I; Poirier, G et al

in Journal of Sleep Research (2010), 19(Suppl. 2),

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See detailEffects of aging and daytime recovery sleep on N-REM slow oscillations
Lafortune, M; Viens, I; Poirier, J et al

Poster (2009, April)

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See detailN-REM sleep slow oscillations amplitude and density in the young and middle-aged men and women
Viens, I; Lafortune, M; Poirier, G et al

Poster (2009, April)

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See detailEffects of consolidation of procedural motor memory traces on slow and fast spindles
Barakat, M; Doyon, J; Debas, K et al

Poster (2009, April)

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See detailTime-of-day changes in brain motor activity
Vandewalle, Gilles ULg; Doyon, J; Debas, K et al

in Sleep (2009), 32(Suppl. 1),

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See detailEffects of aging and daytime recovery sleep on N-REM slow oscillations
Lafortune, M; Viens, I; Poirier, G et al

in Sleep (2009), 32(Suppl. 1),

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See detailN-REM sleep slow oscillations amplitude and density in the young and middle-aged men and women
Viens, I; Lafortune, M; Poirier, G et al

in Sleep (2009), 32(Suppl. 1),

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