Neural models of modulation frequency analysis in the auditory system

Více o knize

This thesis aims at understanding the processing of amplitude modulated (AM) acoustic stimuli in the mammalian auditory system. A biologically motivated neural model of AM processing has been developed. The first main component of the model allows for the simulation of the response properties of cochlear nucleus ideal onset units, a neuron type that is known to encode the modulation frequency of AM stimuli by its distinct temporal responses. The second model component consists of a neural circuit that transforms temporal AM information, provided by the ideal onset model, into a rate-based representation of AM information. This rate-based representation is given by modulation-frequency selective neurons exhibiting bandpass shaped rate modulation transfer functions with different best modulation frequencies. The neural model allows for encoding the modulation content of a variety of AM stimuli. In the third part of the thesis, the model is further extended in order to compare the simulation results to the amplitude modulation filter concept derived from recent psychoacoustical data. Overall, the biologically motivated neural model is found to be in line with results from both neurophysiological recordings and psychoacoustic concepts and might therefore provide an important step towards a better quantitative understanding of the AM processing principles in the mammalian auditory system. engl.