| Popis: |
The third Institute of Neurobiology of the Mediterranean Sea (INMED) conference in La Ciotat –the second INMED conference organised with TINS – focussed on one of the most important neurotransmitters: GABA. GABA was considered until recently a fossil topic but, like the phoenix, GABA is rising from the ashes. GABAergic synapses and networks are probably now the most actively investigated domain of integrative and basic neurobiology. This is owing to convergence of fundamental observations, including the roles of oscillations in neuronal networks, the ability of GABA to shift its actions depending on intracellular Cl− concentrations during maturation and neurological disorders, and the modulation by neuronal activity of GABA actions and plasticity. The discovery that GABAergic interneurons are so heterogeneous (see the TINS Interneuron Diversity series) did not discourage neurobiologists from working on what could have seemed a mess; rather, it stimulated experiments and imagination. One reason for that is the unprecedented development of imaging, physiological, molecular and mathematical techniques that enable the role of a given neuron and the behaviour of its network to be studied in parallel, revealing both the tree and the forest.As at preceding INMED meetings, the convergence of a beautiful site, speakers with very different backgrounds and agreeable conditions led to many debates and provided the ingredients for success. The meeting was organised along a series of fundamental topics.(i) Developmental aspects of GABA actions were addressed by leading experts including Nick Spitzer, Kai Kaila, Guosong Liu, John Huang, Evelyn Sernagor and Rustem Khazipov. The topic is discussed in this issue of TINS by Karl Kandler, who elegantly showed the role of GABAergic synapses in the construction of networks for primary sound localization. In addition, Yehezkel Ben-Ari and Alfonso Represa discuss the trophic roles of GABA during early brain development, and how the excitatory activity of GABA contributes to these actions.(ii) The multiple facets of GABA actions and its underlying mechanisms were addressed by several speakers, including Chris McBain, Christophe Bernard and Dimitri Kullmann. The topic is represented here by Alain Marty, who describes a novel regulatory mechanism of intracellular Cl−, and by Allyson Howard, Gabor Tamas and Ivan Soltesz. They describe axo-axonic cells that, although endowed with highly specialized output domains, display astonishing versatility in their effects on postsynaptic targets. Rafael Gutierrez reports his interesting observations on how the same synapses – the notoriously complex and attractive mossy fibre synapses – can release in some conditions (during development and after seizures) both GABA and glutamate.(iii) Oscillations and GABA mechanisms received at the meeting the interest they deserve, with talks by Moshe Abeles, by Thomas Klausberger and Peter Somogyi in a illuminating duo, and by Rosa Cossart, who elegantly demonstrated use of the two-photon microscope in dissecting the mechanisms that generate oscillations. The topic is represented here by Rodolfo Llinas and colleagues, who describe how GABA sculpts cortical activation precisely and resets ongoing oscillations at the thalamic level, most notably in relation to the sleep–wake cycle. Shaul Hestrin and Mario Galarreta remind us of the important role of gap junctions in oscillations.(iv) The relationship between epilepsies and GABA is a historical and very important topic, characterized by complexity, change and controversy. It was presented at the meeting by Istvan Mody, who described the tonic currents in epilepsies, and by Richard Miles, who described the shift of GABA activity in human epileptics. Tamas Freund and Zsofia Magloczky review here the roles of interneuron death and reorganization in epilepsies, and notably in human epilepsies. Using in vivo recordings – almost a trademark of his approach – Mircea Steriade reviews the role of thalamic reticular neurons in the initiation of physiological and pathological oscillations (spindles and spike-wave seizures). The excitation of reticular thalamic neurons by cortical neurons during Lennox–Gastaut seizures leads to prolonged inhibitory postsynaptic potentials in thalamocortical neurons, which obliterate signals from the external world.The program of the next La Ciotat INMED conference is now available (see announcement in TINS and http://www.inmednet.com), This meeting is also a satellite of the International Epilepsy Congress in Paris and will focus on ‘nature and nurture in brain development and neurological disorders’. This meeting will be diverse, dealing with the roles of environment and genes in network formation and language acquisition, autism and brain development, and the permanent effects seizures and other insults on the brain. The clinical implications will be dealt with extensively, by comparing state-of-the-art basic and clinical science. We look forward to welcoming you to La Ciotat in early September. |
Full Text from ScienceDirect