Inmed - Séminaires externes - Neurobiologie - Juin-juillet 2017

Publié le par ANAE

Les séminaires externes qui auront lieu à l'INMED (Conference room)

en juin & juillet

 

Prochains séminaires à venir

 

Rappel ! Lundi 26 juin à 11h : Dr. Sophie UGOLINI (niversity of Buffalo Centre d'Immunologie de Marseille Luminy - CIML) "Neuroendocrine regulation of immunity" invitée par Françoise MUSCATELLI

 

The survival of living organisms depends on their capacity to mount a defense against environmental agents that cause tissue damage and infection. Traditionally, the activity of the immune system in repairing tissue injury and combating pathogens has been considered quite different from that of the nervous system, which transduces environmental or internal damaging signals into electrical activity to produce reflexes and sensations. However, anatomical and cellular bases for bidirectional interactions between these two systems have been established. We are investigating how neural and immune signals are interconnected and integrated to shape the host response to pathogens and injuries. Stress can be defined as a state of altered homeostasis resulting from external or internal stimuli, including inflammatory processes, infections and pain. In response to these stimuli, various adaptive neuroendocrine mechanisms are induced to restore homeostasis. Part of this response is initiated within the central nervous system and translated into action by the hypothalamic-pituitary-adrenal (HPA) axis. This neuroendocrine pathway has been shown to modulate inflammatory and immune responses but the precise molecular and cellular mechanisms remain unclear. In addition, sensory nerves are stimulated when an injury, an infection or an inflammation occurs in tissues. These neurons convey the damaging information to the brain (inducing pain) and release a number of mediators and neuropeptides in situ that can modulate the function of immune cells locally. By studying these pathways, we identified new regulatory mechanisms revealing a role of the nervous system in immunity.

 

 

Nouveauté ! Mercredi 28 juin à 11h : Dr. Gaëtan LESCA (Centre de Recherche en Neurosciences de Lyon (CRNL) Department of Mathematics U1028) "Use of next generation sequencing to improve gene discovery and diagnostic yield in neurodevelopmental disorders" invité par Igor MEDYNA

 

During the last years, major advances have been performed in the molecular basis of epileptic disorders, thanks to novel technological developments such as molecular cytogenetics and multiple parallel sequencing. In addition to gene identification, these technologies have also proved to be powerful tools for genetic diagnosis in various types of Mendelian epilepsies and especially in epileptic encephalopathies, that is a highly heterogeneous group of disorders. These techniques currently include gene panels and whole-exome sequencing and are being constantly improved. Accurate molecular diagnosis puts an end to extensive and repeated etiological screening and is mandatory for accurate genetic counselling which is a frequent request in families with young children affected with epileptic encephalopathies. It will also pave the way for developing novel therapeutic strategies.

 

 

Rappel Vendredi 30 juin à 11h : Dr Kishore KUCHIBOTHLA (New York University School of Medecine, NY) "Neural circuitry for context-dependent behavior and learning" invité par Aurélie CARABALONA & Marco BOCCHIO

 

Sensory stimuli convey critical information about various types of opportunities and threats, including access to nourishment, the presence of predators, or the needs of infants. The same sensory stimulus, however, can have different interpretations based on learned associations and the contexts within which it is presented. How does the brain enable such interpretation of sensory cues based on behavioral context? A major challenge in neural systems is to provide logic to complex neural dynamics. In this talk, I will present a cohesive model, based on experiments in mice and theory, which shows how parallel processing of cholinergic modulation by diverse cortical interneurons enables the same sensory stimuli to trigger different behaviors depending on context. Surprisingly, excitatory synaptic inputs themselves are only modestly affected by context. Instead, during active engagement, cholinergic input co-activates multiple interneurons thereby adjusting inhibitory synaptic inputs and consequently modulating neuronal output. A network model captured these dynamics across neuronal subtypes only when neuromodulation coincidently drove inhibitory and disinhibitory circuit elements, ruling out either as sole computational responses to cholinergic modulation.

I will then share preliminary data and modeling related to the neural circuits that control associative learning. My central hypothesis is that neural activity in auditory cortex promotes associative learning and performance by relating three distinct features: sensory inputs, reward, and context. I propose that identifying the neural substrates of learning, therefore, demands an experimental and theoretical approach that dissociates these aspects and explores their discrete contributions.

 

 

Nouveauté ! Lundi 3 juillet à 11h : Dr. Laura COLGIN (Center for Learning and Memory, The University of Texas at Austin "Slow and fast gamma rhythms in the hippocampus" invitée par Jérôme EPSZTEIN

 

Gamma rhythms are a widespread type of rhythm in the brain and have been linked to functions such as attentional selection and memory. In the hippocampus, a key brain region for memory, accumulating evidence suggests that gamma rhythms comprise two distinct subtypes, slow (~40 Hz) and fast (~80 Hz) gamma. Slow and fast gamma rhythms occur at different times and are entrained by different hippocampal inputs. During slow gamma, hippocampal subfield CA1 is coupled with neighboring subfield CA3, an area involved in memory retrieval. During fast gamma, CA1 is linked with inputs from the medial entorhinal cortex, a region that transmits current spatial information. Yet, the question of whether slow and fast gamma subtypes are functionally distinct is still debated. In this lecture, I present results that support the hypothesis that slow and fast gamma rhythms perform different mnemonic functions.

 

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