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See detailNeural correlates of sleep spindles as revealed by simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (FMRI)
Schabus, M.; Dang-Vu, T.; Balteau, Evelyne ULg et al

in Journal of Sleep Research (2006, September), 15(Suppl. 1), 50-51

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See detailNeural correlates of tic generation in Tourette syndrome: an event-related functional MRI study.
Bohlhalter, Stephan; Goldfine, Andrew; Matteson, S. et al

in Brain : A Journal of Neurology (2006), 129(Pt 8), 2029-37

Little is known about the neural correlates of tics and associated urges. In the present study, we aimed to explore the neural basis of tics in patients with Tourette syndrome by using event-related ... [more ▼]

Little is known about the neural correlates of tics and associated urges. In the present study, we aimed to explore the neural basis of tics in patients with Tourette syndrome by using event-related functional MRI (fMRI). Ten patients (6 women, 4 men; age: mean +/- SD = 31 +/- 11.2) were studied while spontaneously exhibiting a variety of motor and vocal tics. On the basis of synchronized video/audio recordings, fMRI activities were analysed 2 s before and at tic onset irrespective of the clinical phenomenology. We identified a brain network of paralimbic areas such as anterior cingulate and insular cortex, supplementary motor area (SMA) and parietal operculum (PO) predominantly activated before tic onset (P < 0.05, corrected for multiple comparisons). In contrast, at the beginning of tic action, significant fMRI activities were found in sensorimotor areas including superior parietal lobule bilaterally and cerebellum. The results of this study indicate that paralimbic and sensory association areas are critically implicated in tic generation, similar to movements triggered internally by unpleasant sensations, as has been shown for pain or itching. [less ▲]

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See detailThe neural correlates of updating information in verbal working memory
Van der Linden, Martial ULg; Collette, Fabienne ULg; Salmon, Eric ULg et al

in Memory (1999), 7(5-6), 549-560

The aim of the present study was to re-examine cerebral areas subserving the updating function of the central executive with a running span task requiring subjects to watch strings of consonants of ... [more ▼]

The aim of the present study was to re-examine cerebral areas subserving the updating function of the central executive with a running span task requiring subjects to watch strings of consonants of unknown length and then to recall serially a specific number of recent items. In order to dissociate more precisely the updating process from the storage function, a four-item instead of a six-item memory load was used, contrary to our previous study (Salmon et al., 1996). In addition, a serial recall procedure was preferred to a recognition procedure in order to suppress the use of visuospatial strategies. The most significant increase of rCBF occurred in the left frontopolar cortex (Brodmann's area 10), spreading to the left middle frontal (Brodmann's area 46). Results suggest that frontopolar activation underlies an updating process in working memory. [less ▲]

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See detailThe neural correlates of verbal short-term memory in Alzheimer's disease: an fMRI study.
Peters, Fréderic; Collette, Fabienne ULg; Degueldre, Christian ULg et al

in Brain : A Journal of Neurology (2009), 132(7), 1833-1846

Although many studies have shown diminished performance in verbal short-term memory tasks in Alzheimer's disease, few studies have explored the neural correlates of impaired verbal short-term memory in ... [more ▼]

Although many studies have shown diminished performance in verbal short-term memory tasks in Alzheimer's disease, few studies have explored the neural correlates of impaired verbal short-term memory in Alzheimer's disease patients. In this fMRI study, we examined alterations in brain activation patterns during a verbal short-term memory recognition task, by differentiating encoding and retrieval phases. Sixteen mild Alzheimer's disease patients and 16 elderly controls were presented with lists of four words followed, after a few seconds, by a probe word. Participants had to judge whether the probe matched one of the items of the memory list. In both groups, the short-term memory task elicited a distributed fronto-parieto-temporal activation that encompassed bilateral inferior frontal, insular, supplementary motor, precentral and postcentral areas, consistent with previous studies of verbal short-term memory in young subjects. Most notably, Alzheimer's disease patients showed reduced activation in several regions during the encoding phase, including the bilateral middle frontal and the left inferior frontal gyri (associated with executive control processes) as well as the transverse temporal gyri (associated with phonological processing). During the recognition phase, we found decreased activation in the left supramarginal gyrus and the right middle frontal gyrus in Alzheimer's disease patients compared with healthy seniors, possibly related to deficits in manipulation and decision processes for phonological information. At the same time, Alzheimer's disease patients showed increased activation in several brain areas, including the left parahippocampus and hippocampus, suggesting that Alzheimer's disease patients may recruit alternative recognition mechanisms when performing a short-term memory task. Overall, our results indicate that Alzheimer's disease patients show differences in the functional networks underlying memory over short delays, mostly in brain areas known to support phonological processing or executive functioning. [less ▲]

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See detailThe neural correlates of visual self-recognition
Devue, Christel ULg; Brédart, Serge ULg

in Consciousness and Cognition (2011), 20

This paper presents a review of studies that were aimed at determining which brain regions are recruited during visual self-recognition, with a particular focus on self-face recognition. A complex ... [more ▼]

This paper presents a review of studies that were aimed at determining which brain regions are recruited during visual self-recognition, with a particular focus on self-face recognition. A complex bilateral network, involving frontal, parietal and occipital areas, appears to be associated with self-face recognition, with a particularly high implication of the right hemisphere. Results indicate that it remains difficult to determine which specific cognitive operation is reflected by each recruited brain area, in part due to the variability of used control stimuli and experimental tasks. A synthesis of the interpretations provided by previous studies is presented. The relevance of using self-recognition as an indicator of self-awareness is discussed. We argue that a major aim of future research in the field should be to identify more clearly the cognitive operations induced by the perception of the self-face, and search for dissociations between neural correlates and cognitive components. [less ▲]

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See detailNeural crest stem cells from adult bone marrow: a new source for cell replacement therapy?
Glejzer, Aneta; Neirinckx, Virginie ULg; Rogister, Bernard ULg et al

in Wislet, Sabine (Ed.) Advance in Regenerative Medicine (2011)

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See detailNeural differentiation potential of human bone marrow-derived mesenchymal stromal cells: misleading marker gene expression
MONTZKA, Katrin; Lassonczyk, Nina; Tschöke, Beate et al

in BMC Neuroscience (2009), 10

Background: In contrast to pluripotent embryonic stem cells, adult stem cells have been considered to be multipotent, being somewhat more restricted in their differentiation capacity and only giving rise ... [more ▼]

Background: In contrast to pluripotent embryonic stem cells, adult stem cells have been considered to be multipotent, being somewhat more restricted in their differentiation capacity and only giving rise to cell types related to their tissue of origin. Several studies, however, have reported that bone marrow-derived mesenchymal stromal cells (MSCs) are capable of transdifferentiating to neural cell types, effectively crossing normal lineage restriction boundaries. Such reports have been based on the detection of neural-related proteins by the differentiated MSCs. In order to assess the potential of human adult MSCs to undergo true differentiation to a neural lineage and to determine the degree of homogeneity between donor samples, we have used RT-PCR and immunocytochemistry to investigate the basal expression of a range of neural related mRNAs and proteins in populations of non-differentiated MSCs obtained from 4 donors. Results: The expression analysis revealed that several of the commonly used marker genes from other studies like nestin, Enolase2 and microtubule associated protein 1b (MAP1b) are already expressed by undifferentiated human MSCs. Furthermore, mRNA for some of the neural-related transcription factors, e.g. Engrailed-1 and Nurr1 were also strongly expressed. However, several other neural-related mRNAs (e.g. DRD2, enolase2, NFL and MBP) could be identified, but not in all donor samples. Similarly, synaptic vesicle-related mRNA, STX1A could only be detected in 2 of the 4 undifferentiated donor hMSC samples. More significantly, each donor sample revealed a unique expression pattern, demonstrating a significant variation of marker expression. Conclusion: The present study highlights the existence of an inter-donor variability of expression of neuralrelated markers in human MSC samples that has not previously been described. This donor-related heterogeneity might influence the reproducibility of transdifferentiation protocols as well as contributing to the ongoing controversy about differentiation capacities of MSCs. Therefore, further studies need to consider the differences between donor samples prior to any treatment as well as the possibility of harvesting donor cells that may be inappropriate for transplantation strategies. [less ▲]

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See detailNeural fate of Mesenchymal Stem Cells and Neural Crest Stem Cells : Which ways to get neurons for cell therapy purpose ?
Neirinckx, Virginie ULg; Coste, Cécile ULg; Rogister, Bernard ULg et al

in Trends in cell signaling pathways in neuronal fate decision (2013)

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See detailNeural mechanisms involved in the detection of our first name : A combined ERPs and PET study
Perrin, Fabien; Maquet, Pierre ULg; Peigneux, Philippe ULg et al

in Neuropsychologia (2005), 43(1), 12-19

In everyday social interactions, hearing our own first name captures our attention and gives rise to a sense of self-awareness, since it is one of the most socially self related stimulus. In the present ... [more ▼]

In everyday social interactions, hearing our own first name captures our attention and gives rise to a sense of self-awareness, since it is one of the most socially self related stimulus. In the present study, we combined ERPs and PET scan methods to explore the cerebral mechanisms underlying the detection of our own name. While categorical analyses of PET data failed to reveal significant results, we found that the amplitude of the P3 component, elicited when hearing one's own name, correlates with regional cerebral blood changes in right superior temporal sulcus, precuneus and medial prefrontal cortex. Additionally, the latter was more correlated to the P3 obtained for the subject's name compared to that obtained for other first names. These results suggest that the medial prefrontal cortex plays the most prominent role in self-processing. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailNeural mechanisms of antinociceptive effects of hypnosis.
Faymonville, Marie ULg; Laureys, Steven ULg; Degueldre, Christian ULg et al

in Anesthesiology (2000), 92(5), 1257-67

BACKGROUND: The neural mechanisms underlying the modulation of pain perception by hypnosis remain obscure. In this study, we used positron emission tomography in 11 healthy volunteers to identify the ... [more ▼]

BACKGROUND: The neural mechanisms underlying the modulation of pain perception by hypnosis remain obscure. In this study, we used positron emission tomography in 11 healthy volunteers to identify the brain areas in which hypnosis modulates cerebral responses to a noxious stimulus. METHODS: The protocol used a factorial design with two factors: state (hypnotic state, resting state, mental imagery) and stimulation (warm non-noxious vs. hot noxious stimuli applied to right thenar eminence). Two cerebral blood flow scans were obtained with the 15O-water technique during each condition. After each scan, the subject was asked to rate pain sensation and unpleasantness. Statistical parametric mapping was used to determine the main effects of noxious stimulation and hypnotic state as well as state-by-stimulation interactions (i.e., brain areas that would be more or less activated in hypnosis than in control conditions, under noxious stimulation). RESULTS: Hypnosis decreased both pain sensation and the unpleasantness of noxious stimuli. Noxious stimulation caused an increase in regional cerebral blood flow in the thalamic nuclei and anterior cingulate and insular cortices. The hypnotic state induced a significant activation of a right-sided extrastriate area and the anterior cingulate cortex. The interaction analysis showed that the activity in the anterior (mid-)cingulate cortex was related to pain perception and unpleasantness differently in the hypnotic state than in control situations. CONCLUSIONS: Both intensity and unpleasantness of the noxious stimuli are reduced during the hypnotic state. In addition, hypnotic modulation of pain is mediated by the anterior cingulate cortex. [less ▲]

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See detailA neural network controller for hydronic heating systems of solar buildings
Argiriou, A.; Bellas-Velidis, I.; Kummert, M. et al

in Neural Networks (2004), 17

An artificial neural network (ANN)-based controller for hydronic heating plants of buildings is presented. The controller has forecasting capabilities: it includes a meteorological module, forecasting the ... [more ▼]

An artificial neural network (ANN)-based controller for hydronic heating plants of buildings is presented. The controller has forecasting capabilities: it includes a meteorological module, forecasting the ambient temperature and solar irradiance, an indoor temperature predictor module, a supply temperature predictor module and an optimizing module for the water supply temperature. All ANN modules are based on the Feed Forward Back Propagation (FFBP) model. The operation of the controller has been tested experimentally, on a real-scale office building during real operating conditions. The operation results were compared to those of a conventional controller. The performance was also assessed via numerical simulation. The detailed thermal simulation tool for solar systems and buildings TRNSYS was used. Both experimental and numerical results showed that the expected percentage of energy savings with respect to a conventional controller is of about 15% under North European weather conditions. [less ▲]

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See detailNeural network involved in self-judgment in young and elderly adults
Feyers, Dorothée ULg

Master of advanced studies dissertation (2008)

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See detailNeural network involved in self-judgment in young and elderly adults
Feyers, Dorothée ULg; Collette, Fabienne ULg; D'Argembeau, Arnaud ULg et al

Poster (2008, May 29)

In agreement with the literature, we have recently observed that the ventro-medial prefrontal cortex (VMPFC) is activated both in young and elderly subjects during a adjective judgment task requiring ... [more ▼]

In agreement with the literature, we have recently observed that the ventro-medial prefrontal cortex (VMPFC) is activated both in young and elderly subjects during a adjective judgment task requiring judgment about self vs. other in the context of a first (1PP) or third (3PP) perspective-taking (Ruby et al., submitted). Here, we have performed functional connectivity analyses to determine the network of cerebral areas associated to the performance of young and elderly subjects. <br />Results indicate that, in the 1PP condition, activity of the VMPFC is related to the inferior frontal gyrus, parahippocampal gyrus in elderly but to the occipital cortex only in young subjects. In the 3PP condition, functional connectivity exist between the VMPFC and medial frontal gyrus, inferior frontal gyrus and superior temporal areas in elderly, but with occipital and parietal areas only in young subjects. <br />The cerebral areas associated to VMPFC activity in young subjects were previously described as involved both in autobiographical memory retrieval and mentalizing processes. With regard to elderly, the cerebral network evidenced is related to retrieval of semantic and episodic memories (parahippocampal and superior temporal) but also to the attribution of emotional valence to the adjectives (inferior frontal) and perspective taking (medial frontal gyrus). <br />These results indicate (1) that the VMPFC is connected to a larger cerebral network in elderly than in young subjects during self judgements; (2) that young subjects perform the task on the basis of autobiographical information retrieval only, while elderly subjects use supplementary, more reflexive, cognitive processes. [less ▲]

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See detailNeural network involved in young and elderly adults
Feyers, Dorothée ULg; Collette, Fabienne ULg; D'Argembeau, Arnaud ULg et al

in Proceedings of the Cognitive Aging Conference (2008, April 11)

In agreement with the literature, we have recently observed that the ventro-medial prefrontal cortex (VMPFC) is activated both in young and elderly subjects during a adjective judgment task requiring ... [more ▼]

In agreement with the literature, we have recently observed that the ventro-medial prefrontal cortex (VMPFC) is activated both in young and elderly subjects during a adjective judgment task requiring judgment about self vs. other in the context of a first (1PP) or third (3PP) perspective-taking (Ruby et al., submitted). Here, we have performed functional connectivity analyses to determine the network of cerebral areas associated to the performance of young and elderly subjects. Results indicate that, in the 1PP condition, activity of the VMPFC is related to the medial orbito-frontal, posterior and inferior temporal and parietal areas in elderly, but to the occipital cortex only in young subjects. In the 3PP condition, functional connectivity exist between the VMPFC and posterior temporal and lateral orbito-frontal areas in elderly, but with occipital and parietal areas only in young subjects. The cerebral areas associated to VMPFC activity in young subjects were previously described as involved both in autobiographic memory retrieval and mentalizing processes. With regard to elderly, the cerebral network evidenced is related to autobiographic memory retrieval (parietal and temporal areas) but also to the attribution of emotional valence to the adjectives (medial orbito-frontal) and perspective taking both in 1PP and 3PP conditions (lateral orbito-frontal). These results indicate (1) that the VMPFC is connected to a larger cerebral network in elderly than in young subjects during self judgements; (2) that young subjects perform the task on the basis of autobiographical information retrieval only, while elderly subjects use supplementary, more reflexive, cognitive processes. [less ▲]

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See detailA neural network model of sensitization of evoked cortical responses in migraine
Thomas, E.; Sandor, P. S.; Ambrosini, A. et al

in Cephalalgia : An International Journal of Headache (2002), 22(1), 48-53

Migraine patients show abnormalities of cerebral electrophysiology that manifest themselves mainly during the attack interval. Cortical-evoked potentials of migraineurs fail to habituate to repetitive ... [more ▼]

Migraine patients show abnormalities of cerebral electrophysiology that manifest themselves mainly during the attack interval. Cortical-evoked potentials of migraineurs fail to habituate to repetitive presentations of visual stimuli, and the amplitude of components of their auditory cortical-evoked potentials have a higher dependence on the stimulus intensities than in healthy subjects. A computer model of a neural hetwork has been developed that is able to reproduce both these neurophysiological dysfunctions. It predicts a positive correlation between the magnitudes of both these dysfunctions. The model also offers an explanation of why mutations in the same ion channel gene with opposite consequences on channel function, e.g. P/Q Ca2+ channels in migraine, may lead to similar electrophysiological abnormalities. [less ▲]

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See detailNeural networks for musical chords recognition
Osmalsky, Julien ULg; Embrechts, Jean-Jacques ULg; Van Droogenbroeck, Marc ULg et al

in Journées d'informatique musicale (2012, May)

In this paper, we consider the challenging problem of music recognition and present an effective machine learning based method using a feed-forward neural network for chord recognition. The method uses ... [more ▼]

In this paper, we consider the challenging problem of music recognition and present an effective machine learning based method using a feed-forward neural network for chord recognition. The method uses the known feature vector for automatic chord recognition called the Pitch Class Profile (PCP). Although the PCP vector only provides attributes corresponding to 12 semi-tone values, we show that it is adequate for chord recognition. Part of our work also relates to the design of a database of chords. Our database is primarily designed for chords typical of Western Europe music. In particular, we have built a large dataset filled with recorded guitar chords under different acquisition conditions (instruments, microphones, etc), but also with samples obtained with other instruments. Our experiments establish a twofold result: (1) the PCP is well suited for describing chords in a machine learning context, and (2) the algorithm is also capable to recognize chords played with other instruments, even unknown from the training phase. [less ▲]

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See detailNeural networks for short-term memory for order differentiate high and low proficiency bilinguals
Majerus, Steve ULg; Belayachi, Sanaa ULg; De Smedt, Bert et al

in NeuroImage (2008), 42

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See detailNeural networks involved in self-judgement in young and elderly adults
Feyers, Dorothée ULg; Collette, Fabienne ULg; D'Argembeau, Arnaud ULg et al

in NeuroImage (2010)

Recent studies have shown that both young and elderly subjects activate the ventromedial prefrontal cortex (VMPFC) when they make self-referential judgements. However, the VMPFC might interact with ... [more ▼]

Recent studies have shown that both young and elderly subjects activate the ventromedial prefrontal cortex (VMPFC) when they make self-referential judgements. However, the VMPFC might interact with different brain regions during self-referencing in the two groups. In this study, based on data from Ruby et al (2009), we have explored this issue using psychophysiological interaction analyses. Young and elderly participants had to judge adjectives describing personality traits in reference to the self versus a close friend or relative (the other), taking either a first-person or a third-person perspective. The physiological factor was the VMPFC activity observed in all participants during self judgement, and the psychological factor was the self versus other referential process. The main effect of first-person perspective in both groups revealed that the VMPFC was coactivated with the left parahippocampal gyrus and the precuneus for self versus other judgments. The main effect of age showed a stronger correlation between activity in the VMPFC and the lingual gyrus in young compared to elderly subjects. Finally, in the interaction, the VMPFC was specifically co-activated with the orbitofrontal gyrus and the precentral gyrus when elderly subjects took a first-person perspective for self judgements. No significant result was observed for the interaction in young subjects. These findings show that, although the VMPFC is engaged by both young and older adults when making self-referential judgements, this brain structure interacts differently with other brain regions as a function of age and perspective. These differences might reflect a tendency by older people to engage in more emotional/social processing than younger adults when making self-referential judgements with a first-person perspective [less ▲]

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