Analysis of Dynamic Spectra in Ferret Primary Auditory Cortex. 2. Prediction of Unit Responses to Arbitrary Dynamic Spectra
Technical research rept.
MARYLAND UNIV COLLEGE PARK INST FOR SYSTEMS RESEARCH
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Acoustic stimuli with broadband dynamic spectra evoke strong and relatively sustained responses in neurons of the primary auditory cortex AI de Ribaupierre et al. 1972, Eggermont 1994, Kowalski et al. 1995. The response patterns reflect details of both the spectral shape and its changes in time. To characterize these neurons or units, elementary broad-band spectra with envelopes sinusoidally modulated on a logarithmic axis ripples were presented over a wide range of parameters such as ripple frequencies, phases, and velocities Kowalski et al. 1995. A typical and most prominent feature of the responses is the synchronized component which tracks the periodicity of the stimulus envelope. The amplitude and phase of this component could be measured from period histograms of the neural responses and plotted against different stimulus parameters, thus obtaining a variety of transfer functions. For example, the response component as a function of ripple frequency is the ripple transfer function, whose inverse Fourier transform is the response field of the unit RF. Similarly, the response as a function of ripple velocity gives the temporal transfer function and its inverse transform, the temporal impulse response IR.
- Fluid Mechanics