Analog LSI implementation of biological direction-selective neurons

A direction-selective motion-detection network is implemented into analog metal-oxide-semiconductor (MOS) circuits. The network, based on biological direction-selective (DS) neurons, was constructed with three functional components that act as an elementary motion detector, a dendritic tree and a cell body in a DS neuron. The elementary motion detector and dendritic tree were realized using a novel current-mode delay line circuit. Since the delay line circuit utilized a Miller capacitance caused by the Miller effect and a parasitic capacitance, the occupied area of the network on a LSI chip was reduced effectively. Therefore, it is possible to reduce an occupied area of the network effectively in a LSI chip. Simulation results using the simulation program with integrated circuit emphasis (SPICE) showed that the network operated with the directional selectivity of an object motion. A two-dimensional direction selective network was designed for a LSI, which detects the two-dimensional motion of an object. This simple network has the potential to enable forming motion-detection systems without arithmetic calculation.