Biological modeling of vertebrate retina: Rod cell to bipolar cell

Advances in retinal research has recently enabled significant development in the arena of biomedical prostheses, thus enhancing the quality of therapeutic healthcare for patients suffering from retinal disorders. All vertebrates have complex vision systems, and mapping these neuroanatomical processes into a hardware platform to mimic retinal functionality is yet to be successful. A thorough understanding of the multifaceted cellular system and the neurons within the retina is a key requirement for implementation as a hardware device. Instead of modeling the full signal flow pathway of undetermined retinal features which remain to be experimentally validated, this paper hones in specifically on the known interactions between the retinal rod cells and bipolar cells. This is performed by introducing biochemical theory, dynamical analysis and presenting a biological signal flow architecture of the outer layer of the retina, from the photoreceptor to the bipolar cell through chemical synapses. The model is comprised of a numerical system based on the Hodgkin Huxley equations. This approach provides an acceptable replication of the dynamics of action potentials within the neuron. Numerical simulations for the signal flow model, represented by a system of nonlinear differential equations, are performed in order to provide a detailed analysis for a neuron's response under varying light conditions.