Neuron types, intrinsic circuits, and plasticity in the inferior colliculus

The inferior colliculus is a critical auditory center in the midbrain which virtually acts as a hub of all ascending and descending auditory information flows. Wide variety of neuronal responses to sound is found in the IC, and this variety emerges not only from the wide range of extrinsic afferent inputs, but also from the complex features of the local circuits in the IC, for example, the mosaic pattern of extrinsic fiber termination, the various neuronal types each of which compose different patterns of local connection, and the unique forms of synaptic plasticity de novo. This chapter reviews the recent progress in understanding these features, and identifies the key issues for future research.