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Massimo Avoli"Fast Oscillation, GABA Synchronization and Epileptiform Discharges"

Abstract :

GABA is the main inhibitory neurotransmitter in the adult forebrain where it activates ionotropic type A and metabotropic type B receptors. GABAA receptor-mediated inhibition controls neuronal excitability and thus the occurrence of seizures. However, more complex, and at times unexpected, mechanisms of GABAergic signaling have been reported over the last few years. In this seminar, we will review experimental data that point at a peculiar role played by GABAA receptor-mediated mechanisms in synchronizing neuronal networks, expecially those of limbic structures such as the hippocampus, the entorhinal and perirhinal cortices, or the amygdala. In particular, we will analyze their role in the generation of high-frequency oscillations and their contribution to epileptiform synchronization. Whether and how GABAA receptors influence the interaction between limbic networks leading to ictogenesis will be also reviewed. Finally, we will consider the potential role of high-frequency oscillations in epileptogenesis.

Selected publications

Contact size does not affect high frequency oscillation detection in intracerebral EEG recordings in a rat epilepsy model.Châtillon CE, Zelmann R, Bortel A, Avoli M, Gotman J.Clin Neurophysiol. 2011 Mar 21. [Epub ahead of print]
High-frequency (80-500 Hz) oscillations and epileptogenesis in temporal lobe epilepsy.Lévesque M, Bortel A, Gotman J, Avoli M.Neurobiol Dis. 2011 Jun;42(3):231-41. Epub 2011 Jan 14.
Curia G, Papouin T, Séguéla P, Avoli M. Downregulation of Tonic GABAergic Inhibition in a Mouse Model of Fragile X Syndrome. Cereb Cortex. 2008 Sep 11.

Scientific focus :

Dr. Massimo Avoli uses electrophysiological and molecular techniques to examine the excitability of forebrain neurons in rats and mice. His work focuses on the interplay of inhibitory and excitatory influences, especially as they relate to the genesis of synchronicity in neuronal networks. These processes are fundamental for understanding the mechanisms underlying the generation of seizures in epileptic patients and for developing new anti-epileptic drugs. In his recent research, Dr. Avoli has worked with a mouse model of Fragile X syndrome to identify the alterations in inhibition that occur in a specific brain structure, the subiculum. This aspect might represent a fundamental mechanism in the pathophysiogenesis of this form of mental retardation.

Stéphane Oliet