Objectif The objectives of the project are related to an important problem of the modern neuroscience - neuronal mechanisms of memory. To attack this problem, reduced variants of the known experimental paradigms of long-term potentiation (LTP) and depression (LTD) will be used so that LTP and LTD-like phenomena (e.g. lasting increases and decreases in synaptic strength) will be induced by intracellular current injections in single neurons. Comparative analysis of similar plasticity phenomena at different objects (isolated central nervous of the snail, mammalian hippocampal areas CA1 and CA3, in vivo neocortex and hippocampus) will be done. Several electrophysiological (extra- and intracellular recordings including dendritic recordings) and optical methods (voltage and calcium sensitive fluorescence) will be applied to study contribution of postsynaptic activation into induction of these types of long-lasting synaptic plasticities and their relationship with conventional LTP/LTD (induced by high-frequency activation of afferent inputs). Mechanisms of a novel effect of "supralinear" increase in postsynaptic responses during hyperpolarization and aftereffects of such an increase will be studied. More specifically, involvement of increased intracellular concentration of Ca2+ ions and also dependence of the magnitude and direction of the induced synaptic modifications on the initial efficacy of synaptic inputs, on their dendritic location and other conditions will be investigated in similar sets of experiments by different groups.Several statistical methods (component, quantal, fluctuation, correlation analyses) added by pharmacological tests will be used to specify contribution of presynaptic (increased quantal release) and postsynaptic mechanisms (e.g. increased quantal efficacy) in the maintenance of the lasting synaptic plasticities. Parallel computer simulation experiments are planned in addition to the in vitro and in vivo electrophysiological experiments to test involvement of respective presynaptic and postsynaptic mechanisms. The results are expected to essentially advance understanding neuronal mechanisms of long-term synaptic plasticities, e.g. specify contribution of pre- and postsynaptic mechanisms in both their induction and maintenance. Therefore the hypothesis will be tested and specified on generality of involvement on postsynaptic mechanisms into induction of persistent synaptic modifications in the vertebrate and invertebrate brain and in different structures of the vertebrate brain. Also the hypothesis will be tested on involvement in maintenance of these modifications of both pre- (changes in quantal release) and postsynaptic (efficacy of a transmitter quantum) mechanisms. Relative contribution of pre- and postsynaptic mechnaims will be evaluated. Novel recording techniques will be introduced in the eastern and novel computational techniques also in the western teams. Programme(s) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Thème(s) 4 - Life Sciences OPEN - OPEN Call Appel à propositions Data not available Régime de financement Data not available Coordinateur International School for Advanced Studies Contribution de l’UE Aucune donnée Adresse Via Beirut 2-4 34014 Trieste Italie Voir sur la carte Coût total Aucune donnée Participants (7) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire Brain Research Institute Russie Contribution de l’UE Aucune donnée Adresse per. Obukha 5 103064 Moscow Voir sur la carte Coût total Aucune donnée M.V. Lomonosov Moscow State University Russie Contribution de l’UE Aucune donnée Adresse Vorobjevy Gory 119899 Moscow Voir sur la carte Coût total Aucune donnée National Academy of Science of Belarus Biélorussie Contribution de l’UE Aucune donnée Adresse Academicheskaya Street 28 220725 Minsk Voir sur la carte Coût total Aucune donnée Russian Academy of Sciences Russie Contribution de l’UE Aucune donnée Adresse Butlerova 5A 117865 Moscow Voir sur la carte Coût total Aucune donnée Tbilisi Medical University Géorgie Contribution de l’UE Aucune donnée Adresse 6 Jacob Nikoladze Street 380079 Tbilisi Voir sur la carte Coût total Aucune donnée Technische Universität München Allemagne Contribution de l’UE Aucune donnée Adresse Biedersteiner Str. 29 80802 München Voir sur la carte Coût total Aucune donnée University of Bristol Royaume-Uni Contribution de l’UE Aucune donnée Adresse University Walk Street BS8 1TD Bristol Voir sur la carte Coût total Aucune donnée