Lieu: Auditorium Médiathèque Jacques Ellul – Pessac

from Marsicano's lab will give a presentation entitled 'Sport : quand la motivation dépasse la raison'


Pour plus de détails: https://www.bordeaux-neurocampus.fr/event/conference-a-pessac/

The astrocyte, an intimate partner of neurons.

After obtaining a bachelor's and master's degree in Cellular Biology and Physiology at the University of Bordeaux 2, I realized that understanding how synapses work is a key element in understanding how information is transmitted in the brain. In September 2002, I joined Dr. Dominique Poulain's laboratory (INSERM 378, Morphofunctional Neurobiology unit) to do my DEA internship in Neurosciences and Neuropharmacology, under the supervision of Dr. Stéphane Oliet. This laboratory mainly worked on the plasticity of a neuroendocrine system, the hypothalmo-neuro-pituitary system, involved in several essential functions for our body. During my DEA, I characterized the subtype of metabotropic glutamate receptor involved in regulating the efficacy of glutamatergic and GABAergic synaptic transmission in the supraoptic nucleus.

Very quickly, in contact with Dr. Stéphane Oliet and Dr. Dionysia Theodosis, I realized that to better understand brain transmission, it was necessary to integrate a partner who was previously ignored: the astrocyte. I therefore decided to do my thesis (September 2003 - December 2006) under the supervision of Dr. Stéphane Oliet. First, we demonstrated that the efficacy of glutamatergic synaptic transmission can be increased or decreased persistently in the supra-optic nucleus, as is the case in other structures such as the hippocampus. These long-term synaptic plasticity phenomena are dependent on the activation of NMDA-type postsynaptic glutamatergic receptors. Activation of NMDA receptors requires the concomitant binding of two ligands, glutamate at the glutamate binding site and a coagonist, glycine or D-serine, at the glycine binding site. We have shown that D-serine, synthesized by astrocytes of the supraoptic nucleus, is the only endogenous ligand of the NMDA receptor glycine site in this structure in adults. Our work has shown that astrocytes, by releasing D-serine, control the activity of NMDA receptors and therefore long-term synaptic plasticity.

At the end of my thesis, the classical vision stipulated that astrocytes were able to detect synaptic activity only when it was important and involved the simultaneous activation of several synapses. However, as I showed during my doctoral work that astrocytes control the activity of NMDA receptors under conditions of basal synaptic transmission, at the end of my thesis I was convinced that communication between astrocytes and neurons could be done in response to very low levels of synaptic activity. In January 2007, I joined the laboratory of Professor Richard Robitaille, of the University of Montreal (Montreal, Canada), one of the international leaders in the field of interactions between neurons and glial cells. The work I did under his direction revealed for the first time that astrocytes were able to detect the activity of individual synapses and modulate their functions in return.

In order to better understand the role of astrocytes in synaptic transmission, we need to better understand the morphological interaction of the astrocyte element with the neural elements of the synapse. It is to answer this problem that I carried out a last year of post-doctoral studies (June 2011-September 2012) in the teams of Dr. Stéphane Oliet (Neurocentre Magendie) and Professor Valentin Nägerl (IINS, Bordeaux), a specialist in super-resolution microscopy (STED).

In October 2012, I was recruited from the Centre National de la Recherche Scientifique, in the Glie-neurone Relations group headed by Dr. Stéphane Oliet, at the Neurocentre Magendie. The aim of my work is to better understand how an astrocyte, in close interaction with more than 100,000 synapses, is able to adequately regulate all the synapses with which it interacts. In addition, on the basis of this work I am trying to understand whether a modification of the astrocyte-neurone interaction would be involved in certain brain pathologies.


Jury
Mrs Nathalie ROUACH, DR INSERM, Collège de France, Paris (Rapporteur)
Mr Richard ROBITAILLE, Professor, Université de Montréal, Montreal, Candada (Rapporteur)
Mr Luc PELLERIN, Associate Professor, University of Lausanne, Switzerland (Rapporteur)
Mr. Charles BOURQUE, Professor, McGill University, Canada (Examiner)
Mr. Etienne AUDINAT, DR CNRS, Institut de genénomique fonctionnelle, Montpellier (Examiner)
Mr Stéphane OLIET, DR CNRS, Neurocentre Magendie, Bordeaux (Examiner)

Translated with www.DeepL.com/Translator
Date de la soutenance: 23/09/2019 - 14h00
Lieu: Neurocentre Magendie Seminar room

Lieu: Auditorium Centre Broca Nouvelle Aquitaine

Organised by: Maurice Garret – Nathalie Sans – Mathieu Letellier


Pour plus de détails: https://www.bordeaux-neurocampus.fr/en/journee-synapse/

from Stephane Oliet's lab will give a presentation entitled 'Using brain connectivity to unravel cognitive mechanisms in neurological disorders'
Date de la soutenance: 17/09/2019 - 14h30
Lieu: salle "module 2.6” (Bâtiment du CROUS)

Pour plus de détails: https://www.bordeaux-neurocampus.fr/event/soutenance-de-these-ismail-koubiyr/

from Frick's lab will give a presentation entitled 'The role of intrinsic neuronal excitability for Prelimbic network function'
Date de la soutenance: 13/09/2019 - 14h00
Lieu: PGF

from Oliet's lab will give a presentation entitled "L’astrocyte, intégrateur et régulateur de l’activité synaptique excitatrice dans des conditions physiologiques et pathologiques"
Date de la soutenance: 20/06/2019 - 14h30
Lieu: Neurocentre Magendie Seminar room

from Montcouquiol-Sans's lab will give a presentation entitled ...
Date de la soutenance: 17/06/2019 - 13h30
Lieu: Neurocentre Magendie Seminar room

Lieu: Amphi Centre Broca

Dr. Julia Lemos is an Assistant Professor at the Department of Neuroscience of the University of Minnesota (USA) and will present the work of her lab dissecting the actions of corticotropin releasing factor (CRF) in the nucleus accumbens.
Host: Anna Beyeler

Outside of its well-characterized actions in the HPA axis, the stress-associated peptide corticotropin-releasing factor (CRF) regulates neuronal excitability and synaptic transmission in several extrahypothalamic brain regions. Previous research has shown that CRF in the nucleus accumbens (NAc) promotes appetitive behavior through mechanisms that remain poorly understood. We have recently showed that CRF potentiates both dopaminergic and cholinergic transmission in the NAc. However, it is unknown how CRF regulates the activity of medium spiny neurons (MSNs), the principle projection neurons of the NAc, to modulate behavioral output. MSNs are classified by their peptide expression and projection targets within the basal ganglia: dMSNs form the direct projection pathway and express dynorphin, whereas iMSNs form the indirect pathway and express enkephalin. RNAscope in situ hybridization was used to assess Crh1 mRNA expression in MSN subpopulations, identifying dMSNs and iMSNs with expression of dynorphin (pdyn) or enkephalin (pEnk), respectively. 20% of all cells were positive for Crh1 mRNA, with approximately 30% co-expressing pEnk mRNA (iMSNs), 30% co-expressing pDyn mRNA (dMSNs) and 30% co-expressing neither marker. Using whole-cell patch clamp electrophysiology recordings in brain slices, we examined the function of exogenously-applied CRF on the excitability of MSNs in the NAc core. Application of 100 nM CRF produced a leftward shift in the current-voltage relationship, demonstrating that CRF can enhance the firing rate of both dMSNs and iMSNs. Next steps will focus on identifying the role of CRF receptor subtypes in enhancing the spiking activity in MSNs and elucidate whether this effect is through direct actions on MSNs or through dopaminergic and cholinergic modulation of MSNs.


Pour plus de détails: https://www.lemoslaboratory.org/