RESUMO
We propose a biological cortical column model, at an intermediate mesoscopic scale, in order to better understand and interpret biological sources of voltage-sensitive dye imaging signal (VSD signal). To perform a quantitative analysis of the relative contributions to the VSD signal, a detailed compartmental model was developed at a scale corresponding to one pixel of optical imaging. The generated model was used to solve the VSD direct problem, i.e. generate a VSD signal, given the neural substrate parameters and activities. Here, we confirm and quantify the fact that the VSD signal is the result of an average from multiple components. Not surprisingly, the compartments that mostly contribute to the signal are the upper layer dendrites of excitatory neurons. However, our model suggests that inhibitory cells, spiking activity and deep layers contributions are also significant and, more unexpected, are dynamically modulated with time and response strength.
Assuntos
Córtex Cerebral/fisiologia , Processamento de Imagem Assistida por Computador , Modelos Neurológicos , Vias Aferentes/citologia , Vias Aferentes/fisiologia , Algoritmos , Biofísica , Calibragem , Corantes , Dendritos/fisiologia , Estimulação Elétrica , Eletrofisiologia , Humanos , Modelos Estatísticos , Rede Nervosa/citologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Sinapses/fisiologia , Tálamo/fisiologiaRESUMO
In this review, we present the voltage-sensitive dye imaging (VSDI) method. The possibility offered for in vivo (and in vitro) brain imaging is unprecedented in terms of spatial and temporal resolution. However, the unresolved multi-component origin of the optical signal encourages us to perform a detailed analysis of the method limitation and the existing models. We propose a biophysical model at a mesoscopic scale in order to understand and interpret this signal.
