A functional model of the slope sensitivity of the primary auditory cortex neurons in awake cats

Our measurement of single-spike responses to tone-burst stimuli showed that there are heterogenic response types of the primary auditory cortex (A1) neurons in awake cats: phasic neurons sensitive to stimulus amplitude-rise-slope at the onset of stimuli, sustained cells sensitive to the stimulus slope, and the steady state level at later time-phase of stimuli. In this study, in order to explain the behavior of the slope-sensitive phasic cells, an auditory model has been developed. The model consists of six stages: the inner hair cell (IHC), the primary auditory nerve (AN), the cochlear nucleus (CN), the inferior colliculus (IC), the medial geniculate body (MGB), and the A1 neuron. The model was implemented as a MATLAB program on a personal computer using Meddis’s model for IHC [R. Meddis, J. Acoust. Soc. Am. 79, 702-711 (1986)] and Maki’s model for AN, CN, and IC [Maki et al., J. Acoust. Soc. Jpn. 60, 304-313 (2000)], while the models of MGB and A1 neuron were newly developed. The model output successfully replicated the physiological data in terms of response rise-time, maximum driven rate, and onset-latency corresponding to the slopes of input stimuli. [Work supported by KAKENHI 20300076.]