Actualités : A la une !S'abonner au Flux RSS
A.Contarino & N. Morisot dans Neuropharmacology
29 avr. 2016
CRF1 and the CRF2 receptor are essential ...► En savoir +
Jérôme Badaut, L. Hirt et al. dans J Cereb Blood Flow Metab.
13 avr. 2016
grant from the Swiss National Science...► En savoir +
Symposium - 3° CONFÉRENCE BORDEAUX NEUROCAMPUS
3 jours de conférences; 20 conférenciers...► En savoir +
P.Branchereau, D.Cattaert et al. dans Scientific Reports
25 avr. 2016
mouse spinal motoneurons (MNs)...► En savoir +
Séminaire - Mike Murphy
27 mai 2016 à 11:30 - Salle de conférence Magendie
..surprising mechanism led up to develop further► En savoir +
4-Hz oscillations synchronize prefrontal-amygdala circuits during fear behavior.4-Hz oscillations synchronize prefrontal-amygdala circuits during fear behavior.
Fear expression relies on the coordinated activity of prefrontal and amygdala circuits, yet the mechanisms allowing long-range network synchronization during fear remain unknown. Using a combination of extracellular recordings, pharmacological and optogenetic manipulations, we found that freezing, a behavioral expression of fear, temporally coincided with the development of sustained, internally generated 4-Hz oscillations in prefrontal-amygdala circuits. 4-Hz oscillations predict freezing onset and offset and synchronize prefrontal-amygdala circuits. Optogenetic induction of prefrontal 4-Hz oscillations coordinates prefrontal-amygdala activity and elicits fear behavior. These results unravel a sustained oscillatory mechanism mediating prefrontal-amygdala coupling during fear behavior. Karalis N, Dejean C, Chaudun F, Khoder S, Rozeske RR, Wurtz H, Bagur S, Benchenane K, Sirota A, Courtin J, Herry C.
Nat Neurosci. 2016 Feb 15.
Depolarizing GABA/glycine synaptic events switch from excitation to inhibition during frequency increases.Depolarizing GABA/glycine synaptic events switch from excitation to inhibition during frequency increases.
By acting on their ionotropic chloride channel receptors, GABA and glycine represent the major inhibitory transmitters of the central nervous system. Nevertheless, in various brain structures, depolarizing GABAergic/glycinergic postsynaptic potentials (dGPSPs) lead to dual inhibitory (shunting) and excitatory components, the functional consequences of which remain poorly acknowledged. Indeed, the extent to which each component prevails during dGPSP is unclear. Understanding the mechanisms predicting the dGPSP outcome on neural network activity is therefore a major issue in neurobiology. By combining electrophysiological recordings of spinal embryonic mouse motoneurons and modelling study, we demonstrate that increasing the chloride conductance (gCl) favors inhibition either during a single dGPSP or during trains in which gCl summates. Finally, based on this summation mechanism, the excitatory effect of EPSPs is overcome by dGPSPs in a frequency-dependent manner. These results reveal an important mechanism by which dGPSPs protect against the overexcitation of neural excitatory circuits. Branchereau P, Cattaert D, Delpy A, Allain AE, Martin E, Meyrand P.
Sci Rep. 2016 Feb 25;6:21753
Nutritional n-3 PUFA Deficiency Abolishes Endocannabinoid Gating of Hippocampal Long-Term Potentiation.Nutritional n-3 PUFA Deficiency Abolishes Endocannabinoid Gating of Hippocampal Long-Term Potentiation.
Maternal n-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid, is critical during perinatal brain development. How early postnatal n-3 PUFA deficiency impacts on hippocampal synaptic plasticity is mostly unknown. Here we compared activity-dependent plasticity at excitatory and inhibitory synapses in the CA1 region of the hippocampus in weaned pups whose mothers were fed with an n-3 PUFA-balanced or n-3 PUFA-deficient diet. Normally, endogenous cannabinoids (eCB) produced by the post-synapse dually control network activity by mediating the long-term depression of inhibitory inputs (iLTD) and positively gating NMDAR-dependent long-term potentiation (LTP) of excitatory inputs. We found that both iLTD and LTP were impaired in n-3 PUFA-deficient mice. Pharmacological dissection of the underlying mechanism revealed that impairment of NMDAR-dependent LTP was causally linked to and attributable to the ablation of eCB-mediated iLTD and associated to disinhibitory gating of excitatory synapses. The data shed new light on how n-3 PUFAs shape synaptic activity in the hippocampus and provide a new synaptic substrate to the cognitive impairments associated with perinatal n-3 deficiency. Thomazeau A, Bosch-Bouju C, Manzoni O, Layé S.
Cereb Cortex. 2016 Mar 5
Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices.Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices.
Single-molecule imaging has changed the way we understand many biological mechanisms, particularly in neurobiology, by shedding light on intricate molecular events down to the nanoscale. However, current single-molecule studies in neuroscience have been limited to cultured neurons or organotypic slices, leaving as an open question the existence of fast receptor diffusion in intact brain tissue. Here, for the first time, we targeted dopamine receptors in vivo with functionalized quantum dots and were able to perform single-molecule tracking in acute rat brain slices. We propose a novel delocalized and non-inflammatory way of delivering nanoparticles (NPs) in vivo to the brain, which allowed us to label and track genetically engineered surface dopamine receptors in neocortical neurons, revealing inherent behaviour and receptor activity regulations. We thus propose a NP-based platform for single-molecule studies in the living brain, opening new avenues of research in physiological and pathological animal models. Varela JA, Dupuis JP, Etchepare L, Espana A, Cognet L, Groc L.
Nat Commun. 2016 Mar 14;7:10947
The CRF1 and the CRF2 receptor mediate recognition memory deficits and vulnerability induced by opiate withdrawal.The CRF1 and the CRF2 receptor mediate recognition memory deficits and vulnerability induced by opiate withdrawal.
Opiate use disorders are associated with impaired cognitive function and altered stress-responsive systems. The corticotropin-releasing factor (CRF) system mediates stress responses via CRF1 and CRF2 receptors and may be implicated in substance use disorders. However, the specific role for each of the two known CRF receptor subtypes in cognitive impairment induced by opiate administration and withdrawal remains to be elucidated. In the present study, CRF1-/-, CRF2-/- and their respective wild-type mice are injected with escalating doses of morphine and cognitive function assessed by the novel object recognition (NOR) memory task throughout relatively long periods of opiate withdrawal. Early (2 days) phases of opiate withdrawal impair NOR memory in wild-type, CRF1-/- and CRF2-/- mice. However, the duration of opiate withdrawal-induced NOR memory deficits is prolonged in CRF1-/- but shortened in CRF2-/- mice, as compared to their respective wild-type mice, indicating opposite roles for the two CRF receptor subtypes. Nevertheless, following apparent recovery, exposure to an environmental stressor induces the reemergence of NOR memory deficits in long-term opiate-withdrawn wild-type but not CRF1-/- or CRF2-/- mice, indicating an essential role for both CRF receptor subtypes in stress vulnerability. These findings bring initial evidence of a complex physiopathological role for the CRF system in cognitive deficits and the long-lasting vulnerability induced by opiate drugs. Morisot N, Contarino A.
Neuropharmacology. 2016 Feb 18
The globus pallidus pars interna in goal-oriented and routine behaviors: Resolving a long-standing paradox.The globus pallidus pars interna in goal-oriented and routine behaviors: Resolving a long-standing paradox.
There is an apparent contradiction between experimental data showing that the basal ganglia are involved in goal-oriented and routine behaviors and clinical observations. Lesion or disruption by deep brain stimulation of the globus pallidus interna has been used for various therapeutic purposes ranging from the improvement of dystonia to the treatment of Tourette's syndrome. None of these approaches has reported any severe impairment in goal-oriented or automatic movement.
To solve this conundrum, we trained 2 monkeys to perform a variant of a 2-armed bandit-task (with different reward contingencies). In the latter we alternated blocks of trials with choices between familiar rewarded targets that elicit routine behavior and blocks with novel pairs of targets that require an intentional learning process.
Bilateral inactivation of the globus pallidus interna, by injection of muscimol, prevents animals from learning new contingencies while performance remains intact, although slower for the familiar stimuli. We replicate in silico these data by adding lateral competition and Hebbian learning in the cortical layer of the theoretical model of the cortex-basal ganglia loop that provided the framework of our experimental approach.
The basal ganglia play a critical role in the deliberative process that underlies learning but are not necessary for the expression of routine movements. Our approach predicts that after pallidotomy or during stimulation, patients should have difficulty with complex decision-making processes or learning new goal-oriented behaviors. Piron C, Kase D, Topalidou M, Goillandeau M, Orignac H, N'Guyen TH, Rougier N, Boraud T.
Mov Disord. 2016 Feb 22
25 mai 2016
Un projet de décret doit annuler 256 millions de crédits pour la recherche et l’enseignement supérieur. Sept Prix Nobel – dont deux de l’université de...► Lire la suite
19 mai 2016
La conception de l'expérience joue sur le fait que les humains trouvent généralement leur chemin dans la vie en utilisant deux formes distinctes de re...► Lire la suite
9 mai 2016
Dans Nature , combien de calories les humains et les singes brûlent ils chaque jour? En comparaison avec les chimpanzés et d'autres singes, nos moteu...► Lire la suite
EMPLOIS - JOB OPPORTUNITIES +
Post-doc positions open / Team leader
Recherchons ! Recrutement d’un Ingénieur d’Etude « en Biologie Moléculaire et Cellulaire » INSERM . L’équipe « Polarité Planaire et Plasticité » qui vient d’être labélisée Equipe FRM 2016 recrute un ingénieur d’étude en CDD, responsable de son activité de biologie...
Stages / Internship....
Job opportunities outside Bordeaux... 1 Poste d'ingénieur en Auvergne + 1 poste d'ingénieur à Toulouse.....
Participez à une étude sur le sommeil
Le virtuel au service de la santé
Pierre Philip, de la FBN et ses ambassadeurs de la réalité...
- février 2016
- mars 2016
- avril 2016
- mai 2016
- juin 2016
- juillet 2016
- septembre 2016
- octobre 2016