Bron, France
Bron, France
Time filter
Source Type

Di Rienzo F.,University Claude Bernard Lyon 1 | Guillot A.,University Claude Bernard Lyon 1 | Guillot A.,Institut Universitaire de France | Daligault S.,CERMEP | And 4 more authors.
Neurocase | Year: 2014

The neurophysiological substrates underlying motor imagery are now well established. However, the neural processes of motor inhibition while mentally rehearsing an action are poorly understood. This concern has received limited experimental investigations leading to divergent conclusions. Whether motor command suppression is mediated by specific brain structures or by intracortical facilitation/inhibition is a matter of debate. Interestingly, although motor commands are inhibited during motor imagery (MI) in healthy participants, spinal cord injury may result in weakened motor inhibition. Using magentoencephalography, we observed that mental and actual execution of a goal-directed pointing task elicited similar primary motor cortex activation in a C6-C7 quadriplegic patient, thus confirming the hypothesis of weakened motor inhibition during MI. In an age-matched healthy control participant, however, primary motor area activation during MI was significantly reduced compared to physical practice. Brain activation during actual movement resulted in enhanced recruitment of premotor areas in the patient. In the healthy participant, we found functional relationships between the primary motor area and peri-rolandic sites including the primary sensory area and the supplementary motor area during MI. This neural network was not activated when the quadriplegic patient performed MI. We assume that the primary sensory area and the supplementary motor area may be part of a functional network underlying motor inhibition during MI. These data provide insights into brain function changes due to neuroplasticity after spinal cord injury and evidence cortical substrates underlying weakened motor inhibition during MI after deafferentation and deefferentation. © 2013 © 2013 Taylor & Francis.

PubMed | University Claude Bernard Lyon 1, CERMEP and Cynbiose SAS
Type: | Journal: Scientific reports | Year: 2016

In this article, we report the safety evaluation of gadolinium-based nanoparticles in nonhuman primates (NHP) in the context of magnetic resonance imaging (MRI) studies in atherosclerosis bearing animals and healthy controls. In healthy NHP, the pharmacokinetics and toxicity profiles demonstrated the absence of dose, time, and sex-effects, as well as a suitable tolerance of intravenous administration of the nanoparticles. We investigated their imaging properties for arterial plaque imaging in a standard diet or a high cholesterol diet NHP, and compared their characteristics with clinically applied Gd-chelate. This preliminary investigation reports the efficient and safe imaging of atherosclerotic plaques.

Fort A.,INRETS | Martin R.,ISH Inc | Jacquet-Andrieu A.,French National Center for Scientific Research | Combe-Pangaud C.,ISH Inc | And 4 more authors.
Brain Research | Year: 2010

It is a well-known fact that attention is crucial for driving a car. This innovative study aims to assess the impact of attentional workload modulation on cerebral activity during a simulated driving task using magnetoencephalography (MEG). A car simulator equipped with a steering wheel, turn indicators, an accelerator and a brake pedal has been specifically designed to be used with MEG. Attentional demand has been modulated using a radio broadcast. During half of the driving scenarios, subjects could ignore the broadcast (simple task, ST) and during the other half, they had to actively listen to it in order to answer 3 questions (dual task, DT). Evoked magnetic responses were computed in both conditions separately for two visual stimuli of interest: traffic lights (from green to amber) and direction signs (arrows to the right or to the left) shown on boards. The cortical sources of these activities have been estimated using a minimum-norm current estimates modeling technique. Results show the activation of a large distributed network similar in ST and DT and similar for both the traffic lights and the direction signs. This network mainly involves sensory visual areas as well as parietal and frontal regions known to play a role in selective attention and motor areas. The increase of attentional demand affects the neuronal processing of relevant visual information for driving, as early as the perceptual stage. By demonstrating the feasibility of recording MEG activity during an interactive simulated driving task, this study opens new possibilities for investigating issues regarding drivers' activity. © 2010 Elsevier B.V. All rights reserved.

Glaser B.,University of Geneva | Lothe A.,Center Dexploration Et Of Recherche Medicale Par Emission Of Positons Cermep | Chabloz M.,University of Geneva | Dukes D.,University of Geneva | And 3 more authors.
American Journal on Intellectual and Developmental Disabilities | Year: 2012

The authors developed a computerized program, Vis-à-Vis (VAV), to improve socioemotional functioning and working memory in children with developmental disabilities. The authors subsequently tested whether participants showed signs of improving the targeted skills. VAV is composed of three modules: Focus on the Eyes, Emotion Recognition and Understanding, and Working Memory. Ten children with idiopathic developmental delay completed four 20-min weekly sessions of VAV for 12 weeks with an adult. Participants were evaluated before (Time 0) and after (Time 1) training and 6 months after remediation (Time 2). Subjects improved on all three modules during training and on emotion recognition and nonverbal reasoning post-VAV. These gains were still present at Time 2. VAV is a promising new tool for working on socioemotional impairments in hardto- treat pediatric populations. © EAAIDD.

Ballanger B.,French National Center for Scientific Research | Klinger H.,University of Lyon | Eche J.,Hospices Civils de Lyon | Lerond J.,Hospices Civils de Lyon | And 9 more authors.
Movement Disorders | Year: 2012

Depression is frequent in Parkinson's disease, but its pathophysiology remains unclear. Two recent studies have investigated the role of serotonergic system at the presynaptic level. The objective of the present study was to use positron emission tomography and [ 18F]MPPF to investigate the role of postsynaptic serotonergic system dysfunction in the pathophysiology of depression in Parkinson's disease. Four parkinsonian patients with depression and 8 parkinsonian patients without depression were enrolled. Each patient underwent a scan using [ 18F]MPPF, a selective serotonin 1A receptor antagonist. Voxel-by-voxel statistical comparison of [ 18F]MPPF uptake of the 2 groups of parkinsonian patients and with 7 matched normal subjects was made using statistical parametric mapping (P uncorrected < .001). Compared with nondepressed parkinsonian patients, depressed patients exhibited reduced tracer uptake in the left hippocampus, the right insula, the left superior temporal cortex, and the orbitofrontal cortex. Compared with controls, nondepressed parkinsonian patients presented reduced [ 18F]MPPF uptake bilaterally in the inferior frontal cortex as well as in the right ventral striatum and insula. Compared with controls, [ 18F]MPPF uptake was decreased in depressed parkinsonian patients in the left dorsal anterior cingulate and orbitofrontal cortices, in the right hippocampic region, and in the temporal cortex. The present imaging study suggests that abnormalities in serotonin 1A receptor neurotransmission in the limbic system may be involved in the neural mechanisms underlying depression in patients with Parkinson's disease. © 2011 Movement Disorder Society.

Tomei S.,CNRS Research Center for Image Acquisition and Processing for Health | Reilhac A.,CH Lyon Sud | Visvikis D.,French Institute of Health and Medical Research | Boussion N.,CERMEP | And 3 more authors.
IEEE Transactions on Nuclear Science | Year: 2010

The purpose of this paper is to generate and distribute a database of simulated whole body 18F-FDG positron emission tomography (PET) oncology images. As far as we know, this database is the first addressing the need for simulated 18F-FDG PET oncology images by providing a series of realistic whole-body patient images with well-controlled inserted lesions of calibrated uptakes. It also fulfills the requirements of detection performance studies by including normal and pathological cases. The originality of the database is based on three points. First, we built a complex model of 18F-FDG patient based on the Zubal phantom in combination with activity distributions in the main organs of interest derived from a series of 70 clinical cases. Secondly, we proposed a model of lesions extent corresponding to real lymphoma patients. The lesion contrast levels were derived from a human observer detection study so as to cover the entire range of detectability. Lastly, the simulated database was generated with the PET-SORTEO Monte Carlo simulation tool that was fully validated against the geometry of the ECAT EXACT HR+ (CTI/Siemens Knoxville). The oncoPET-DB database is composed of 100 whole-body PET simulated images, including 50 normal cases coming from different realizations of noise of the healthy model and 50 pathological cases including lesions of calibrated uptakes and various diameters. Such a database will be useful to evaluate algorithms that may impact quantification or contrast recovery, to perform observer studies or to assess computer-aided diagnosis methods. Perspectives include enriching the present database with new pathological and normal cases accounting for interindividual variability of anatomy and FDG uptake. © 2010 IEEE.

PubMed | Ruhr University Bochum, French Institute of Health and Medical Research and CERMEP
Type: Journal Article | Journal: Journal of neurophysiology | Year: 2016

It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual phenomena such as tactile sensations being referred from the face to the phantom hand. It is also known that transient increase of hand somatosensory inputs, via repetitive somatosensory stimulation (RSS) at a fingertip, induces local somatosensory discriminative improvement accompanied by cortical representational changes in the primary somatosensory cortex (SI). We recently demonstrated that RSS at the tip of the right index finger induces similar training-independent perceptual learning across the hand-face border, improving somatosensory perception at the lips (Muret D, Dinse HR, Macchione S, Urquizar C, Farn A, Reilly KT.Curr Biol24: R736-R737, 2014). Whether neural plastic changes across the hand-face border accompany such remote and adaptive perceptual plasticity remains unknown. Here we used magnetoencephalography to investigate the electrophysiological correlates underlying RSS-induced behavioral changes across the hand-face border. The results highlight significant changes in dipole location after RSS both for the stimulated finger and for the lips. These findings reveal plastic changes that cross the hand-face border after an increase, instead of a decrease, in somatosensory inputs.

PubMed | Grenoble University Hospital Center, Institut Universitaire de France and CERMEP
Type: Journal Article | Journal: Epilepsia | Year: 2016

Interictal [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) is used in the presurgical evaluation of patients with drug-resistant focal epilepsy. We aimed at clarifying its relationships with ictal high-frequency oscillations (iHFOs) shown to be a relevant marker of the seizure-onset zone.We studied the correlation between FDG-PET and epileptogenicity maps in an unselected series of 37 successive patients having been explored with stereo-electroencephalography (SEEG).At the group level, we found a significant correlation between iHFOs and FDG-PET interictal hypometabolism only in cases of temporal lobe epilepsy. This correlation was found with HFOs, and the same comparison between FDG-PET and ictal SEEG power of lower frequencies during the same epochs did not show the same significance.This finding suggests that interictal FDG-PET and ictal HFOs may share common underlying pathophysiologic mechanisms of ictogenesis in temporal lobe epilepsy, and combining both features may help to identify the seizure-onset zone.

Peyron R.,CHU de Saint Etienne | Peyron R.,French Institute of Health and Medical Research | Faillenot I.,CHU de Saint Etienne | Faillenot I.,French Institute of Health and Medical Research | And 7 more authors.
European Journal of Pain (United Kingdom) | Year: 2013

Background: Brain areas involved in nociception have been repeatedly investigated. Therefore, brain responses to physiological pain conditions are well identified. The same is not true for allodynic pain in patients with neuropathic pain since the cortical reorganizations that are involved in the conversion of non-noxious stimuli into painful sensations still remain unknown. Methods: The present positron emission tomography (PET) study enrolled 19 patients with dynamic mechanical allodynia to brushing or to cold rubbing of the skin. PET activations during allodynic stimulation were compared to those obtained with the same innocuous stimulation applied outside the neuropathic pain area (control). In a second comparison, they were compared with responses to a noxious heat stimulation applied outside the neuropathic pain area (experimental pain). Results: Common responses to allodynia and control stimulations were found in contralateral SI, SII and insula and in ipsilateral cerebellum. Not surprisingly, heat pain condition was associated with activations in contralateral prefrontal and SII cortices and, bilaterally, in the anterior insular cortices. Distinctive cortical responses between control and allodynic conditions were restricted to one activation within the contralateral anterior insula, a region also activated by experimental heat pain. Conclusions: The insular subdivision was inappropriately activated considering the innocuous nature of the stimulus, but adequately activated with regard to pain-evoked sensation. Subcortically, the hypothesis of reorganization at any level of the somatosensory and pain pathways underlying such insular activity was supported by the observed shift of thalamic activation from a lateral-posterior to an anterior-medial position. © 2013 European Federation of International Association for the Study of Pain Chapters.

PubMed | French Institute of Health and Medical Research and CERMEP
Type: | Journal: Journal of Alzheimer's disease : JAD | Year: 2015

Subjective cognitive decline (SCD) may be the first clinical sign of Alzheimers disease (AD). SCD individuals with normal cognition may already have significant hippocampal atrophy, a well-known feature of AD.To test the hypothesis that SCD, compared to healthy individuals without SCD, have a pattern of hippocampal subfield atrophy similar to that measured in the AD pathology.17 SCD, 21 AD, and 40 matched controls underwent a standard T1-weighted MRI and a dedicated high-resolution MRI proton-density hippocampal sequence. For each participant, three hippocampal regions-of-interest were manually delineated on the proton-density hippocampal sequence corresponding to the CA1, subiculum, and other (including CA2-3-4 and dentate gyrus) subfields. Total intracranial volume (TIV)-normalized subfield volumes were compared between-group. Voxelwise group comparisons assessed from the standard T1 MRI were also projected on 3D hippocampal surface views.Both patient groups showed significant TIV-normalized volume decrease in hippocampus global volume and in CA1 and subiculum subfields as well as in the other subfield in AD compared to controls. Significant differences were observed between SCD and AD in hippocampus global TIV-normalized volume. Atrophy maps on hippocampal surface showed major involvement of the lateral part (CA1) in both SCD and AD, with larger overlap of other regions in AD.The findings indicate topographically similar hippocampal subfield changes in SCD individuals as those found in AD. This further highlights the relevance of SCD recruited from a memory clinic in assessing pre-dementia AD stages.

Loading CERMEP collaborators
Loading CERMEP collaborators