The impact of visual perceptual learning on sleep and local slow wave initiation

in Journal of Neuroscience (2013)

Sleep, memory and the hippocampus

in Clinical Neurobiology of the Hippocampus (2012)

A systems-level approach to human REM sleep

in Rapid Eye Movement Sleep: Regulation and Function (2011)

Spontaneous neural activity during human non-rapid eye movement sleep.

in Progress in Brain Research (2011), 193

Recent neuroimaging studies characterized the neural correlates of slow waves and spindles during human non-rapid eye movement (NREM) sleep. They showed that significant activity was consistently ... [more ▼]

Recent neuroimaging studies characterized the neural correlates of slow waves and spindles during human non-rapid eye movement (NREM) sleep. They showed that significant activity was consistently associated with slow (> 140 muV) and delta waves (75-140 muV) during NREM sleep in several cortical areas including inferior frontal, medial prefrontal, precuneus, and posterior cingulate cortices. Unexpectedly, slow waves were also associated with transient responses in the pontine tegmentum and in the cerebellum. On the other hand, spindles were associated with a transient activity in the thalami, paralimbic areas (anterior cingulate and insular cortices), and superior temporal gyri. Moreover, slow spindles (11-13 Hz) were associated with increased activity in the superior frontal gyrus. In contrast, fast spindles (13-15 Hz) recruited a set of cortical regions involved in sensorimotor processing, as well as the mesial frontal cortex and hippocampus. These findings indicate that human NREM sleep is an active state during which brain activity is temporally organized by spontaneous oscillations (spindles and slow oscillation) in a regionally specific manner. The functional significance of these NREM sleep oscillations is currently interpreted in terms of synaptic homeostasis and memory consolidation. [less ▲]

Influence of Brain-Derived Neurotrophic Factor val66met human polymorphism on declarative memory consolidation during sleep

Poster (2010, September 15)

Objectives The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain, regulates long-term potentiation and has been involved in the build up of the homeostatic sleep pressure ... [more ▼]

Objectives The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain, regulates long-term potentiation and has been involved in the build up of the homeostatic sleep pressure in rodents. In humans, valine (val) to methionine (met) substitution in the 5’ pro-region of the BDNF protein is associated with poorer episodic memory. Neurons transfected with met-BDNF-Green Fluorescence Protein showed lower depolarization-induced secretion, while constitutive secretion is unchanged. Here, we hypothesized that the differences in BDNF release determined by this polymorphism would influence sleep-dependent memory consolidation and that in comparison with the met-carriers (val/met or met/met), val/val individuals would show higher memory performance after one night of sleep rather than an immediate retrieval session. Methods Participants encoded a series of neutral faces in the afternoon. Retrieval sessions took place one hour after the encoding session, and in the following morning, after a night of polysomnographic-monitored sleep. During retrieval, studied faces and new ones were presented in random order. For each stimulus, the subjects indicated whether they could retrieve the encoding episode with (“Remember” response), or without details (“know” response), or if they thought the item had not been presented during encoding (“New” response). Results A repeated-measure ANOVA on discrimination index (d’) showed significant effects of group (F(1, 22)=4.66, p=0.042) and session (F(1, 22)=12.21, df=1, p=0.002). Although the group by session interaction was not significant (F(1, 22)=1.84, p=0.188), exploratory planned comparisons showed that at immediate retrieval, d’ was not significantly different between groups (val/val, d’ = 1.94±0.16; met-carriers, d’= 1.61±0.14; p>0.5). In contrast, during the second retest (the next day) d’ in the val/val group (d’=2.56±0.23) was significantly higher than in the met-carriers group (d’=1.88±0.21; p=0.041). Likewise, a between-session enhancement in d’ was detected only in the val/val population (p=0.003). Conclusion Val/val individuals demonstrate higher memory performance than met-carriers after a night of sleep but not at immediate retest. These data suggest that activity-dependent BDNF release promotes memory consolidation during the first post-training hours. Further analysis of the present data set will assess the respective effect of sleep and time on the BDNF-associated delayed memory enhancement. This study was supported by FNRS-FRIA, the University of Liège, and the QEMF. [less ▲]

Neuroimaging Insights into the Dreaming Brain

in Dreams and Dreaming (2010)

Some facts about sleep relevant for Landau-Kleffner syndrome.

in Epilepsia (2009), 50 Suppl 7

Our understanding of the neural mechanisms of non-rapid eye movement sleep (NREM) is steadily increasing. Given the intriguing activation of paroxysmal activity during NREM sleep in patients with Landau ... [more ▼]

Our understanding of the neural mechanisms of non-rapid eye movement sleep (NREM) is steadily increasing. Given the intriguing activation of paroxysmal activity during NREM sleep in patients with Landau-Kleffner syndrome (LKS), a thorough characterization of commonalities and differences between the neural correlates of LKS paroxysms and normal sleep oscillations might provide useful information on the neural underpinning of this disorder. Especially, given the suspected role of sleep in brain plasticity, this type of information is needed to assess the link between cognitive deterioration and electroencephalography (EEG) paroxysms during sleep. [less ▲]