Sensing Sound Through Thalamocortical Afferent Architecture and Cortical Microcircuits

Mammals have multiple cortical fields with neurons responding to the full range of sound frequencies sensed by the sensory epithelium of the ear, the cochlea. At first glance, sensitivities to sound frequency seem highly similar or even redundant across different auditory cortical fields; however, closer inspection reveals marked differences in the architecture of underlying thalamocortical pathways, afferents, and sound sensitivities within each cortical field. Here we summarize the differences in the architecture of the thalamocortical pathway and the termination patterns across auditory cortices. A conceptual framework is presented for how pathway architecture in combination with intrinsic cortical microcircuits can account for observed differences in sound sensitivity. This organization has the capacity to create parallel sound processing streams with diverse and even dynamic sound processing properties.