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Introduction
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Publications
Publications (41)
The development of fast and reproducible motor behavior is a crucial human capacity. The aim of the present study was to address the relationship between the implementation of consistent behavior during initial training on a sequential motor task (the Finger Tapping Task) and subsequent sleep-dependent motor sequence memory consolidation, using fun...
The present study aimed at identifying the neurophysiological responses associated with auditory stimulation during non-rapid eye movement (NREM) sleep using simultaneous EEG/fMRI recordings. It was reported earlier that auditory stimuli produce bilateral activation in auditory cortex, thalamus, and caudate during both wakefulness and NREM-sleep. H...
The present study aimed at identifying the neurophysiological responses associated with auditory stimulation during non-rapid eye movement (NREM) sleep using simultaneous EEG/fMRI recordings. It was reported earlier that auditory stimuli produce bilateral activation in auditory cortex, thalamus, and caudate during both wakefulness and NREM-sleep. H...
Humans are less responsive to the surrounding environment during sleep. However, the extent to which the human brain responds to external stimuli during sleep is uncertain. We used simultaneous EEG and functional MRI to characterize brain responses to tones during wakefulness and non-rapid eye movement (NREM) sleep. Sounds during wakefulness elicit...
The solution of a problem left unresolved in the evening can sometimes pop into mind as a sudden insight after a night of sleep in the following morning. Although favorable effects of sleep on insightful behavior have been experimentally confirmed, the neural mechanisms determining this delayed insight remain unknown. Here, using fMRI, we character...
Memory is constructive in nature so that it may sometimes lead to the retrieval of distorted or illusory information. Sleep facilitates accurate declarative memory consolidation but might also promote such memory distortions. We examined the influence of sleep and lack of sleep on the cerebral correlates of accurate and false recollections using fM...
Sleep promotes memory consolidation, a process by which fresh and labile memories are reorganized into stable memories. Emotional memories are usually better remembered than neutral ones, even at long retention delays. In this study, we assessed the influence of sleep during the night after encoding onto the neural correlates of recollection of emo...
Throughout the day, cognitive performance is under the combined influence of circadian processes and homeostatic sleep pressure. Some people perform best in the morning, whereas others are more alert in the evening. These chronotypes provide a unique way to study the effects of sleep-wake regulation on the cerebral mechanisms supporting cognition....
The pathophysiology of major depressive disorder (MDD) includes both affective and cognitive dysfunctions. We aimed to clarify how regions regulating affective processing interact with those involved in attention, and how such interaction impacts perceptual processing within sensory cortices. Based on previous work showing that top-down influences...
Slow wave sleep (SWS) is associated with spontaneous brain oscillations that are thought to participate in sleep homeostasis and to support the processing of information related to the experiences of the previous awake period. At the cellular level, during SWS, a slow oscillation (<1 Hz) synchronizes firing patterns in large neuronal populations an...
Functional magnetic resonance imaging (fMRI) was used to investigate the cerebral correlates of motor sequence memory consolidation. Participants were scanned while training on an implicit oculomotor sequence learning task and during a single testing session taking place 30 min, 5 hr, or 24 hr later. During training, responses observed in hippocamp...
In addition to classical visual effects, light elicits nonvisual brain responses, which profoundly influence physiology and behavior. These effects are mediated in part by melanopsin-expressing light-sensitive ganglion cells that, in contrast to the classical photopic system that is maximally sensitive to green light (550 nm), is very sensitive to...
After encoding, memory traces are initially fragile and have to be reinforced to become permanent. The initial steps of this process occur at a cellular level within minutes or hours. Besides this rapid synaptic consolidation, systems consolidation occurs within a time frame of days to years. For declarative memory, the latter is presumed to rely o...
Behavioral results Mean values±SEM are plotted. The color of the light corresponds to the bar color. a. D-prime values in the different light conditions (2 sessions per condition) b. Criteria values in the different light conditions (2 sessions per condition) c. Reaction times in the different light conditions (2 sessions per condition) d. Sleepine...
Navigation-related activity in the Natural condition, 72 h post-training. Coordinates x, y, z (mm) are given in standard stereotactic MNI space. Z = Z-statistics value. All regions listed are statistically significant at the p corrected (FWE) <0.05. For brevity, each region is listed only once; when several peaks were observed in the same region, t...
Significant differences between green and violet light conditions at light onset in the left LGN. Left panels: statistical results overlaid to the population mean structural image (puncorrected<0.001). Right panels. Mean parameter estimates of the green and violet light conditions at light onset (arbitrary units±SEM) in the left LGN (−22 −22 −10)....
Emotional events are usually better remembered than neutral ones. This effect is mediated in part by a modulation of the hippocampus by the amygdala. Sleep plays a role in the consolidation of declarative memory. We examined the impact of sleep and lack of sleep on the consolidation of emotional (negative and positive) memories at the macroscopic s...
Effect of Memory
Main effect of memory (R>K) for all subjects during retest. The medial prefrontal, the posterior cingulate cortex/precuneus, and both of the hippocampi show significant responses. Functional results are displayed on the mean structural MR image, normalized to the same stereotactic space (display at p < 0.001 uncorrected).
(8.9 MB T...
Description of Subject Selection and Reference Coordinates Used for Statistical Inferences
(200 KB DOC)
Interaction between Emotion and Memory (Neg>Pos) × (R>K) during the Retest
Psvc: significance after correction for multiple comparisons over a small volume of interest (10-mm sphere).
(26 KB DOC)
In humans, some evidence suggests that there are two different types of spindles during sleep, which differ by their scalp topography and possibly some aspects of their regulation. To test for the existence of two different spindle types, we characterized the activity associated with slow (11–13 Hz) and fast (13–15 Hz) spindles, identified as discr...
Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and th...
In humans, light enhances both alertness and performance during nighttime and daytime [1-4] and influences regional brain function [5]. These effects do not correspond to classical visual responses but involve a non-image forming (NIF) system, which elicits greater endocrine, physiological, neurophysiological, and behavioral responses to shorter li...
Our neurobiological knowledge about human dream organisation results primarily from the study of Rapid-Eye-Movement (REM) sleep. In humans, functional neuroimaging techniques, using H215O or 18FDG positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), allowed the mapping of the regional cerebral activity during this sl...
Human African trypanosomiasis, caused by Trypanosoma brucei (T.b.) gambiense or rhodesiense, evolves in two stages: haemolymphatic stage and meningo-encephalitic stages, the latter featuring numerous neurological disorders. In experimental models infected with diverse T.b. sub-species, body weight (BW) loss, drop in food intake (FI), and hypo-activ...
Patients with human African trypanosomiasis (sleeping sickness) due to the inoculation of Trypanosoma brucei gambiense or rhodesiense show a major disruption of the 24-hour sleep-wake distribution, accompanied by the occurrence of sleep-onset rapid-eye-movement (REM) sleep episodes, proportional to the severity of the illness. Although animal model...
In human African trypanosomiasis (HAT), the parasites invade the central nervous system (CNS), leading to the development of meningo-encephalitis and an irreversible demyelinating process, which kills the patient unless specific treatment is undertaken. Among the experimental trypanocides, the nitroimidazole derivative megazol alone at optimal dose...
Animal models of Human African Trypanosomiasis (HAT) have been developed to understand the pathogenic mechanisms leading to the passage into the neurological phase, most of them referring to histological aspects but not clinical or behavioral data. Our study aimed at defining simple clinical and/or behavioral markers of the passage between the hemo...
