Towards a Unified Model for the Retina - Static vs Dynamic Integrate and Fire Models

Many models have been proposed to describe the visual processing mechanisms in the retina. The spike generation mechanism of the models is typically performed by a Poisson process. Alternatively, a more realistic approach can be used by implementing an integrate and fire mechanism. In this paper we show that the Stochastic Leaky Integrate and Fire (SLIF) model is equivalent to a non-linear Poisson-based model. Furthermore, it proposes a dynamic model for the retina visual processing path, achieved through modulations. For estimating this model a two-step approach is proposed: i) an initial estimation is computed by using a spike-triggered analysis, and ii) the likelihood of the spike train is maximised by gradient ascent.