Seminário com o Prof. Dr. Osame Kinouchi – 19 de dezembro de 2016 – 10h30min

16/12/2016 09:25

O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário: 

em experiência na área de Física Estatística e Sistemas Dinâmicos, atuando principalmente nos seguintes temas: neurociência computacional, meios excitáveis, redes neurais, automata celulares e criticalidade auto-organizada

em experiência na área de Física Estatística e Sistemas Dinâmicos, atuando principalmente nos seguintes temas: neurociência computacional, meios excitáveis, redes neurais, automata celulares e criticalidade auto-organizada

Phase transitions and self-organized criticality in networks of stochastic spiking neurons.

Prof. Dr. Osame Kinouchi

Departamento de Física – FFCLRP – USP

 Resumo:

 Phase transitions and critical behavior are crucial issues both in theoretical and experimental neuroscience. We report analytic and computational results about phase transitions and self-organized criticality (SOC) in networks with general stochastic neurons. The stochastic neuron has a firing probability given by a smooth monotonic function Phi(V) of the membrane potential V, rather than a sharp firing threshold. We find that such networks can operate in several dynamic regimes (phases) depending on the average synaptic weight and the shape of the firing function Phi. In particular, we encounter both continuous and discontinuous phase transitions to absorbing states. At the continuous transition critical boundary, neuronal avalanches occur whose distributions of size and duration are given by power laws, as observed in biological neural networks. We also propose and test a new mechanism to produce SOC: the use of dynamic neuronal gains — a form of short-term plasticity probably in the axon initial segment (AIS) — instead of depressing synapses at the dendrites (as previously studied in the literature). The new self-organization mechanism produces a slightly supercritical state, that we called SOSC, in accord to some intuitions of Alan Turing.

Data: 19 de dezembro de 2016 – (segunda-feira)- Local: Sala 212 – Auditório do Departamento de Física – Horário: 10h30min

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