Design and implementation of a biologically realistic olfactory cortex in analog VLSI

This paper reviews the problem of translating signals into symbols preservi ng maximally the information contained in the signal time structure. In thi s context, we motivate the use of nonconvergent dynamics for the signal to symbol translator. We then describe a biologically realistic model of the o lfactory system proposed by Walter Freeman that has locally stable dynamics but is globally chaotic. We show how we can discretize Freeman "s model us ing digital signal processing techniques, providing an alternative to the m ore conventional Runge-Kutta integration. This analysis leads to a direct m ixed-signal (analog amplitude/discrete time) implementation of the dynamica l building block that simplifies the implementation of the interconnect. We present results of simulations and measurements obtained from a fabricated analog very large scale integration (VLSI) chip.