VLSI implementation of the hippocampal dentate gyrus

The VLSI implementation of a mathematical model of the functional properties of the hippocampal formation has been developed. The hippocampal formation is a brain system which performs the cognitive functions of learning aud memory. The design scheme of analog cellular neural network has been extensively applied. The architecture of the proposed hardware implementation has a topology highly similar to the anatomical structure of the hippocampus, and the dynamical properties of its components are based on experimental characterization of individual hippocampal neurons. The prototype chip with 9 neurons in a two-dimensional 3x3 mesh array occupies a silicon area of 4.6 mm × 6.8 mm and was fabricated in a 2-μm double-polysilicon CMOS technology. According to the SPICE-3 circuit simulator, the response time of each neuron is around 1 μ sec which is much faster than that of the biological neuron.