Michael Roberts, Ph.D.
Associate Professor
Kresge Hearing Research Institute
Department of Otolaryngology-Head and Neck Surgery
University of Michigan
Regulation of sound processing by local circuits in the auditory midbrain
The inferior colliculus (IC) is the midbrain hub of the central auditory system and an important site for computations related to speech processing and sound localization. With more than five times as many neurons as the lower auditory brainstem, the computational potential of the IC is immense, but the cellular and synaptic mechanisms underlying computations in the IC have remained largely unknown. Using a multifaceted approach, we have discovered several of the first molecularly identifiable neuron types in the IC. In addition, the ability to identify and manipulate specific IC neuron types using genetic tools has enabled us to uncover several new mechanisms for how local IC circuits shape the processing of ascending auditory inputs. This seminar will address the challenge of identifying neuron types in the IC and our most recent discoveries of candidate markers for neuron types. It will then focus on several mechanisms that contribute to circuit operations in the IC, with an emphasis on the prevalence of feedforward and recurrent connections. Together, the results will provide new insights into the varied ways that IC circuits shape auditory processing.