Auditory cortical spectral shape analysis in analog VLSI

An analog VLSI circuit used to model spectral shape analysis in the central auditory system is presented. Like the receptive fields of visual cortical neurons, the spectral response fields (SRFs) of neurons in the mammalian primary auditory cortex (AI) resemble localized sinusoids of various phases (i.e., symmetry) and scale (i.e., spectral bandwidth). We use a single circuit building block to model the various response fields. A continuum of asymmetries and bandwidths are obtained by adjusting several offchip parameters. The circuit is to be used for analysis of the auditory spectrum at the output of a silicon cochlea. This scheme is thought to be suitable for the implementation of learning and adaptation in speech recognition and similar applications.