References of "Maquet, Pierre"
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See detailThe role of sleep in the consolidation of emotional memories in humans : a fMRI study
Sterpenich, Virginie; Albouy, Geneviève ULg; Boly, Mélanie ULg et al

Poster (2006)

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See detailEarly boost and slow consolidation in motor skill learning
Hotermans, C.; Peigneux, Philippe ULg; Maertens De Noordhout, Alain ULg et al

in Learning & Memory (Cold Spring Harbor, N.Y.) (2006), 13(5, Sep-Oct), 580-583

Motorskill learning is a dynamic process that continues covertly after training has ended and eventually leads to delayed increments in performance. Current theories Suggest that this off-line improvement ... [more ▼]

Motorskill learning is a dynamic process that continues covertly after training has ended and eventually leads to delayed increments in performance. Current theories Suggest that this off-line improvement takes time and appears only after several hours. Here we show an early transient and short-lived boost in performance, emerging as early as 5-30 min after training but no longer observed 4 h later. This early boost is predictive of the performance achieved 48 h later, Suggesting its functional relevance for memory processes. [less ▲]

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See detailThe left intraparietal sulcus and verbal short-term memory: Focus of attention or serial order ?
Majerus, Steve ULg; Poncelet, Martine ULg; Van der Linden, Martial ULg et al

in Neuroimage (2006), 32(2), 880-891

One of the most consistently activated regions during verbal short-term memory (STM) tasks is the left intraparietal sulcus (IPS). However, its precise role remains a matter of debate. While some authors ... [more ▼]

One of the most consistently activated regions during verbal short-term memory (STM) tasks is the left intraparietal sulcus (IPS). However, its precise role remains a matter of debate. While some authors consider the IPS to be a specific store for serial order information, other data suggest that it serves a more general function of attentional focalization. In the current fMRI experiment, we investigated these two hypotheses by presenting different verbal STM conditions that probed recognition for word identity or word order and by assessing functional connectivity of the left IPS with distant brain areas. If the IPS has a role of attentional focalization, then it should be involved in both order and item conditions, but it should be connected to different brain regions, depending on the neural substrates involved in processing the different types of information (order versus phonological/orthographic) to be remembered in the item and order STM conditions. We observed that the left IPS was activated in both order and item STM conditions but for different reasons: during order STM, the left IPS was functionally connected to serial/temporal order processing areas in the right IPS, premotor and cerebellar cortices, while during item STM, the left IPS was connected to phonological and orthographic processing areas in the superior temporal and fusiform gyri. Our data support a position considering that the left IPS acts as an attentional modulator of distant neural networks which themselves are specialized in processing order or language representations. More generally, they strengthen attention-based accounts of verbal STM. [less ▲]

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See detailA role for sleep in brain plasticity.
Dang Vu, Thien Thanh ULg; Desseilles, Martin ULg; Peigneux, Philippe ULg et al

in Pediatric Rehabilitation (2006), 9(2), 98-118

The idea that sleep might be involved in brain plasticity has been investigated for many years through a large number of animal and human studies, but evidence remains fragmentary. Large amounts of sleep ... [more ▼]

The idea that sleep might be involved in brain plasticity has been investigated for many years through a large number of animal and human studies, but evidence remains fragmentary. Large amounts of sleep in early life suggest that sleep may play a role in brain maturation. In particular, the influence of sleep in developing the visual system has been highlighted. The current data suggest that both Rapid Eye Movement (REM) and non-REM sleep states would be important for brain development. Such findings stress the need for optimal paediatric sleep management. In the adult brain, the role of sleep in learning and memory is emphasized by studies at behavioural, systems, cellular and molecular levels. First, sleep amounts are reported to increase following a learning task and sleep deprivation impairs task acquisition and consolidation. At the systems level, neurophysiological studies suggest possible mechanisms for the consolidation of memory traces. These imply both thalamocortical and hippocampo-neocortical networks. Similarly, neuroimaging techniques demonstrated the experience-dependent changes in cerebral activity during sleep. Finally, recent works show the modulation during sleep of cerebral protein synthesis and expression of genes involved in neuronal plasticity. [less ▲]

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See detailA prominent role for amygdaloid complexes in the Variability in Heart Rate (VHR) during Rapid Eye Movement (REM) sleep relative to wakefulness.
Desseilles, Martin ULg; Dang Vu, Thien Thanh ULg; Laureys, Steven ULg et al

in NeuroImage (2006), 32(3), 1008-1015

Rapid eye movement sleep (REMS) is associated with intense neuronal activity, rapid eye movements, muscular atonia and dreaming. Another important feature in REMS is the instability in autonomic ... [more ▼]

Rapid eye movement sleep (REMS) is associated with intense neuronal activity, rapid eye movements, muscular atonia and dreaming. Another important feature in REMS is the instability in autonomic, especially in cardiovascular regulation. The neural mechanisms underpinning the variability in heart rate (VHR) during REMS are not known in detail, especially in humans. During wakefulness, the right insula has frequently been reported as involved in cardiovascular regulation but this might not be the case during REMS. We aimed at characterizing the neural correlates of VHR during REMS as compared to wakefulness and to slow wave sleep (SWS), the other main component of human sleep, in normal young adults, based on the statistical analysis of a set of (H2O)-O-15 positron emission tomography (PET) sleep data acquired during SWS, REMS and wakefulness. The results showed that VHR correlated more tightly during REMS than during wakefulness with the rCBF in the right amygdaloid complex. Moreover, we assessed whether functional relationships between amygdala and any brain area changed depending the state of vigilance. Only the activity within in the insula was found to covary with the amygdala, significantly more tightly during wakefulness than during REMS in relation to the VHR. The functional connectivity between the amygdala and the insular cortex, two brain areas involved in cardiovascular regulation, differs significantly in REMS as compared to wakefulness. This suggests a functional reorganization of central cardiovascular regulation during REMS. (c) 2006 Elsevier Inc. All rights reserved. [less ▲]

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See detailDaytime light exposure dynamically enhances brain responses.
Vandewalle, Gilles ULg; Balteau, Evelyne ULg; Phillips, Christophe ULg et al

in Current Biology (2006), 16(16), 1616-21

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 ... [more ▼]

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 light wavelengths than to wavelengths geared toward the visual system [6-11]. During daytime, the neural changes induced by light exposure, and their time courses, are largely unknown. With functional magnetic resonance imaging (fMRI), we characterized the neural correlates of the alerting effect of daytime light by assessing the responses to an auditory oddball task [12-15], before and after a short exposure to a bright white light. Light-induced improvement in subjective alertness was linearly related to responses in the posterior thalamus. In addition, light enhanced responses in a set of cortical areas supporting attentional oddball effects, and it prevented decreases of activity otherwise observed during continuous darkness. Responses to light were remarkably dynamic. They declined within minutes after the end of the light stimulus, following various region-specific time courses. These findings suggest that light can modulate activity of subcortical structures involved in alertness, thereby dynamically promoting cortical activity in networks involved in ongoing nonvisual cognitive processes. [less ▲]

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See detailBrain response to one's own name in vegetative state, minimally conscious state and locked-in syndrome
Perrin, F.; Schnakers, Caroline ULg; Schabus, M. et al

in Archives of Neurology (2006), 63

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See detailGemvid, an Open Source, Modular, Automated Activity Recording System for Rats Using Digital Video
Poirrier, Jean-Etienne; Poirrier, Laurent; Leprince, Pierre ULg et al

in Journal of Circadian Rhythms (2006), 4

BACKGROUND: Measurement of locomotor activity is a valuable tool for analysing factors influencing behaviour and for investigating brain function. Several methods have been described in the literature for ... [more ▼]

BACKGROUND: Measurement of locomotor activity is a valuable tool for analysing factors influencing behaviour and for investigating brain function. Several methods have been described in the literature for measuring the amount of animal movement but most are flawed or expensive. Here, we describe an open source, modular, low-cost, user-friendly, highly sensitive, non-invasive system that records all the movements of a rat in its cage. METHODS: Our activity monitoring system quantifies overall free movements of rodents without any markers, using a commercially available CCTV and a newly designed motion detection software developed on a GNU/Linux-operating computer. The operating principle is that the amount of overall movement of an object can be expressed by the difference in total area occupied by the object in two consecutive picture frames. The application is based on software modules that allow the system to be used in a high-throughput workflow. Documentation, example files, source code and binary files can be freely downloaded from the project website at http://bioinformatics.org/gemvid/. RESULTS: In a series of experiments with objects of pre-defined oscillation frequencies and movements, we documented the sensitivity, reproducibility and stability of our system. We also compared data obtained with our system and data obtained with an Actiwatch device. Finally, to validate the system, results obtained from the automated observation of 6 rats during 7 days in a regular light cycle are presented and are accompanied by a stability test. The validity of this system is further demonstrated through the observation of 2 rats in constant dark conditions that displayed the expected free running of their circadian rhythm. CONCLUSION: The present study describes a system that relies on video frame differences to automatically quantify overall free movements of a rodent without any markers. It allows the monitoring of rats in their own environment for an extended period of time. By using a low-cost, open source hardware/software solution, laboratories can greatly simplify their data acquisition and analysis pipelines and improve their workload. [less ▲]

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See detailProton MRS findings in migraine patients during visual stimulation
da Silva, H. M.; Magis, Delphine ULg; Balteau, Evelyne ULg et al

in Cephalalgia : An International Journal of Headache (2005, December), 25(12), 1196

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See detailDiagnostique du syndrome d’apnées et hypopnées obstructives du sommeil par l’analyse des mouvements de la mandibule
Senny, Frédéric ULg; Destiné, Jacques ULg; Ansay, Pierre et al

Conference (2005, November)

Les mouvements de la mandibule donnent une image des efforts respiratoires, particulièrement en période d’apnées et d’hypopnées du sommeil. Ils sont donc une alternative à la pression oesophagienne. Cette ... [more ▼]

Les mouvements de la mandibule donnent une image des efforts respiratoires, particulièrement en période d’apnées et d’hypopnées du sommeil. Ils sont donc une alternative à la pression oesophagienne. Cette étude a mis en évidence le potentiel d’une analyse automatique des mouvements de la mâchoire pour le diagnostique du syndrome d’apnées et hypopnées obstructives du sommeil (SAHOS) par la mesure de l’indice d’apnées et d’hypopnées (IAH). [less ▲]

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See detailCurrent status of brain imaging in sleep medicine
Maquet, Pierre ULg

in Sleep Medicine Reviews (2005), 9(3), 155-156

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See detailAn empirical Bayesian solution to the source reconstruction problem in EEG
Phillips, Christophe ULg; Mattout Jeremie; Rugg, Michael D et al

in Neuroimage (2005), 24(4), 997-1011

Distributed linear solutions of the EEG source localisation problem are used routinely. In contrast to discrete dipole equivalent models, distributed linear solutions do not assume a fixed number of ... [more ▼]

Distributed linear solutions of the EEG source localisation problem are used routinely. In contrast to discrete dipole equivalent models, distributed linear solutions do not assume a fixed number of active sources and rest on a discretised fully 3D representation of the electrical activity of the brain. The ensuing inverse problem is underdetermined and constraints or priors are required to ensure the uniqueness of the solution. In a Bayesian framework, the conditional expectation of the source distribution, given the data, is attained by carefully balancing the minimisation of the residuals induced by noise and the improbability of the estimates as determined by their priors. This balance is specified by hyperparameters that control the relative importance of fitting and conforming to various constraints. Here we formulate the conventional "Weighted Minimum Norm" (WMN) solution in terms of hierarchical linear models. An "Expectation-Maximisation" (EM) algorithm is used to obtain a "Restricted Maximum Likelihood" (ReML) estimate of the hyperparameters, before estimating the "Maximum a Posteriori" solution itself. This procedure can be considered a generalisation of previous work that encompasses multiple constraints. Our approach was compared with the "classic" WMN and Maximum Smoothness solutions, using a simplified 2D source model with synthetic noisy data. The ReML solution was assessed with four types of source location priors: no priors, accurate priors, inaccurate priors, and both accurate and inaccurate priors. The ReML approach proved useful as: (1) The regularisation (or influence of the a priori source covariance) increased as the noise level increased. (2) The localisation error (LE) was negligible when accurate location priors were used. (3) When accurate and inaccurate location priors were used simultaneously, the solution was not influenced by the inaccurate priors. The ReML solution was then applied to real somatosensory-evoked responses to illustrate the application in an empirical setting. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

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See detailA Prominent Role for Amygdaloïd Complexes in the Variability of Heart Rate during Rapid Eye Movement (REM) Sleep
Desseilles, Martin ULg; Dang Vu, Thanh; Laureys, Steven ULg et al

in NeuroImage (2005), 26(Suppl. 1),

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See detailNeural correlates of fast and slow ocular sequence learning
Albouy, Geneviève ULg; Ruby, Perrine; Balteau, Evelyne ULg et al

in NeuroImage (2005), 26(Suppl. 1),

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See detailTime-of-day modulations of rCBF response in functional brain imaging studies: a meta-analysis
Schmidt, Christina; Dang Vu, Thanh; Orban, Pierre et al

in NeuroImage (2005), 26(Suppl. 1),

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See detailBrain imaging on passing to sleep
Maquet, Pierre ULg; Sterpenich, Virginie ULg; Albouy, Geneviève ULg et al

in Parmeggiani, Pier Luigi; Velluti, Ricardo (Eds.) The physiologic nature of sleep (2005)

Detailed reference viewed: 12 (6 ULg)