Eric Boussard, Jean-François Vibert
The fovea of a mammal retina was simulated with its detailed bio(cid:173) logical properties to study the local preprocessing of images. The direct visual pathway (photoreceptors, bipolar and ganglion cells) and the horizontal units, as well as the D-amacrine cells were sim(cid:173) ulated. The computer program simulated the analog non-spiking transmission between photoreceptor and bipolar cells, and between bipolar and ganglion cells, as well as the gap-junctions between hor(cid:173) izontal cells, and the release of dopamine by D-amacrine cells and its diffusion in the extra-cellular space. A 64 x 64 photoreceptors retina, containing 16,448 units, was carried out. This retina dis(cid:173) played contour extraction with a Mach effect, and adaptation to brightness. The simulation showed that the dopaminergic amacrine cells were necessary to ensure adaptation to local brightness.