Real-time emulation of dynamic features of sustained and transient channels in vertebrate retina

In physiological studies conducted thus far, the functional roles of visual neurons have been discussed using models based on the responses of a limited number of neurons to simple visual stimuli. However, these discussions based on simplified inputs do not always hold in the case of highly complex visual environments wherein actual biological vision systems operate. In order to examine and discuss the visual functions of the models, a system that can emulate the responses of a number of model neurons in real time is necessary. Therefore, we have developed a system for the real-time reconstruction of neural images with physiologically reasonable spatiotemporal properties using an analog-digital hybrid system consisting of analog resistive networks, field-programmable gate array (FPGA) circuits, and a digital computer. Here, we conducted emulations for natural scenes with 128 × 128 sustained/transient retinal neurons at 60 frames per second.