Modelos computacionais para o fenÃmeno da depressÃo alastrante: capacidades e limitaÃÃes

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Spreading Depression (SD) is a phenomenon that occurs in the neural tissue, in which, after applying a stimulus, a wave of suppression of the spontaneous neural electrical activity starts propagating from the stimulated point to the neighbor regions. A highlighted characteristic of SD is the propagation of a slow voltage shift wave across the neural tissue concomitantly to the spontaneous neural electrical activity suppression. The phenomenon was first described in 1944 by the professor Aristides A. P. LeÃo and since then, it has been extensively studied, several of its aspects, however, are still not completely understood. Nowadays SD has been studied by the means of mathematical and computational models that aim to reproduce its main characteristics observed in the neural tissue. These models have been used to propose and verify hypotheses about the mechanisms of triggering and propagation of DA. The Almeidaâs et al.(2004) model, in particular, was the first able to reproduce the propagation of the slow voltage variation wave in a three dimensional representation of chicken retina, and for this reason, it was chosen as a base for the construction of a model modified for one dimension, which was implemented and studied in this work. A common characteristic among SD models is the great amount of biological parameters that must to be set in order to execute a simulation. These parameter settings are not easy to be done, since the ranges inside which they produce biologically plausible results are usually not determined. With this in mind, this work presents a methodology to study the parameters of these models and, as a case study, this methodology was applied to verify the capabilities and limitations of the implemented model when representing SD in a different kind of tissue: the rat cerebral cortex. The applied analysis has shown that the model displays a plausible behavior when reproducing several characteristics of SD in rat cortex. The modelâs representation of the slow voltage shift in this tissue is, however, not accurate in some aspects. Nevertheless the presented study made it possible to identify precisely the deficient points of the model and ways to improve it were suggested

ASSUNTO(S)

anÃlise de parÃmetros modelagem computacional spreading depression ciencia da computacao computational modeling parameter analysis depressÃo alastrante

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