MODELLING RESPONSES OF THE PRIMARY AUDITORY CORTEX TO FREQUENCY-MODULATED TONES IN AWAKE CATS

摘要

Responses of primary auditory cortex (A1) neurons to frequency-modulated (FM) tones are heterogenic in awake cats. These neurons include tonic and phasic cells, which show sustained and phasic responses, respectively. FM responses of phasic cells increase as the sweep speed during the frequency modulation increases. In contrast, tonic cell responses decrease with an increase in the sweep speed. To explain the FM responses of A1 neurons, we developed an auditory model with a multichannel neural pathway. The model consists of seven blocks: the basilar membrane (BM), the inner hair cell (IHC), the primary auditory nerve (AN), the ventral cochlear nucleus (VCN), the inferior colliculus (IC), the medial geniculate body (MGB), and the A1 neuron. Weighted summations across the channels were introduced to the VCN, IC, MGB, and A1 blocks because lateral inhibition is observed in these connections. The model output successfully replicated physiological data of the response patterns and the peak-speed relationship in the FM responses. This model can be used to convert acoustical signals into electrical stimuli as part of an auditory brain- machine interface for individuals with severe hearing impairments.