  Sleep slow wave changes during the middle years of life; ; 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 ▲] Detailed reference viewed: 8 (0 ULg)Fast and slow spindle involvement in the consolidation of a new motor sequence; ; 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 ▲] Detailed reference viewed: 19 (4 ULg)NREM slow wave oscillation rebound after sleep deprivation : effect of aging; ; et al Poster (2010, June) Detailed reference viewed: 2 (0 ULg)Age related change in NREM slow oscillations rebound after sleep deprivation; ; et al in Journal of Sleep Research (2010), 19(Suppl. 2), Detailed reference viewed: 5 (2 ULg)N-REM sleep slow oscillations amplitude and density in the young and middle-aged men and women; ; et al Poster (2009, April) Detailed reference viewed: 1 (0 ULg)Effects of consolidation of procedural motor memory traces on slow and fast spindles; ; et al Poster (2009, April) Detailed reference viewed: 1 (0 ULg)Effets de l'âge et de la privation de sommeil sur les oscillations lentes en sommeil NREM; ; et al Poster (2009, March) Detailed reference viewed: 2 (0 ULg) Effects of aging and daytime recovery sleep on N-REM slow oscillations; ; et al in Sleep (2009), 32(Suppl. 1), Detailed reference viewed: 2 (0 ULg)N-REM sleep slow oscillations amplitude and density in the young and middle-aged men and women; ; et al in Sleep (2009), 32(Suppl. 1), Detailed reference viewed: 3 (0 ULg) |
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