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Master's Dissertation
DOI
10.11606/D.59.2001.tde-10022003-182349
Document
Author
Full name
Rodrigo Freire Oliveira
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2001
Supervisor
Committee
Silva Filho, Antonio Carlos Roque da (President)
Costa, Luciano da Fontoura
Silva, Jose Aparecido da
Title in Portuguese
Modelação do processamento neuronal primário no sistema visual de mamíferos.
Keywords in Portuguese
neurociência computacional
redes neurais
sistema visual
Abstract in Portuguese
Desde as descobertas das propriedades dos campos receptivos dos neurônios corticais no córtex visual primário, sua organização tem sido estudada com o auxílio de diversos métodos como eletrofisiologia, imageamento cortical e neurociência computacional. Poucos modelos mostram-se capazes de apresentar dominância ocular e seletividade à orientação simultaneamente. Um modelo em larga escala do sistema visual primário de mamíferos foi construído usando o GENESIS 2.2. O modelo contém aproximadamente 10.000 neurônios biologicamente plausíveis em oito matrizes representando setores das duas retinas, duas lâminas do núcleo geniculado lateral dorsal e duas lâminas representando o córtex visual (cada lâmina composta por uma matriz de células excitatórias e uma matriz de células inibitórias). As propriedades fisiológicas e estruturais do modelo foram determinadas com base em dados experimentais do sistema visual primário de mamíferos. Os neurônios apresentaram respostas binoculares e seletividade à orientação em boa concordância com os resultados experimentais. Apesar de neurônios corticais terem mostrado grande heterogeneidade em seus níveis de seletividade, a latência da resposta manteve-se constante e em boa concordância com resultados experimentais.
Title in English
Modelling the primary neural processing in mammal's visual system.
Keywords in English
computational neuroscience
neural networks
visual system
Abstract in English
Since the discovery of the receptive field properties of cortical neurons in the primary visual cortex, their organization has been studied with many methods ranging from electrophysiology and optical imaging to computational neuroscience. Few models have been capable of showing ocularity and orientation selectivity simultaneously. A large-scale computational model of the mammalian primary visual pathway was constructed using GENESIS 2.2. The model consists of ~10,000 biologically plausible neurons organized in eight arrays to represent sectors of two retinas, two laminae of the dorsal lateral geniculate nucleus and two laminae of the visual cortex (each cortical lamina composed of a matrix of excitatory neurons and a matrix of inhibitory neurons). The physiological and architecture properties of the model were derived from experimental data for the mammalian primary visual pathway. Neurons have shown ocular and orientation selectivity dependent responses in good agreement with data. Though neurons in the cortex have shown markedly heterogeneity in the tuning responses, the latency of response was uniform and in good agreement with reported data.
 
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dissert_mest.pdf (2.48 Mbytes)
Publishing Date
2003-05-22
 
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