Synaptic depression may explain many of the temporal response properties observed in primary auditory cortex: a computational investigation

摘要

In comparison with the speed and precision associated with processing in the auditory periphery, the temporal response properties of neurons in primary auditory cortex (AI) can appear to be surprisingly sluggish. For example, in the thalamocortical transformation of incoming signals a great deal of the temporal fine structure is lost, best modulation frequencies measured in AI are generally below 15 Hz, and the effects of a masker on a probe tone can be detected up to 400 ms after masker offset. The purpose of this study is to explore whether synaptic depression at thalamocortical synapses could explain some of the temporal response properties observed in AI. To explore this hypothesis, a model of cortical synaptic depression was used to investigate the computational properties of a neuron model that included dynamic synapses. Since synaptic depression depends on pre- and not postsynaptic activity, the model also provides a novel account of the effect of subthreshold stimuli.