A phenomenological model of peripheral and central neural responses
to amplitude-modulated tones
Acoustical Society of America, (2004)Abstract
A phenomenological model with time-varying excitation and inhibition
was developed to study possible neural mechanisms underlying changes
in the representation of temporal envelopes along the auditory pathway.
A modified version of an existing auditory-nerve model Zhang et al.,J.
Acoust. Soc. Am. 109, 648–670 (2001) was used to provide inputs
to higher hypothetical processing centers. Model responses were compared
directly to published physiological data at three levels: the auditory
nerve, ventral cochlear nucleus, and inferior colliculus. Trends
and absolute values of both average firing rate and synchrony to the
modulation period were accurately predicted at each level for a wide
range of stimulus modulation depths and modulation frequencies. The
diversity of central physiological responses was accounted for with
realistic variations of model parameters. Specifically, enhanced synchrony
in the cochlear nucleus and rate-tuning to modulation frequency in
the inferior colliculus were predicted by choosing appropriate relative
strengths and
time courses of excitatory and inhibitory inputs to postsynaptic model
cells. The proposed model is fundamentally different than others
that have been used to explain the representation of envelopes in
the mammalian midbrain, and it provides a computational tool for
testing hypothesized relationships between physiology and psychophysics.