Structure and Function of Coordinated Activity in the Auditory System

Abstract Nearly all our knowledge of neuronal processing in the auditory forebrain has come from studies of individual neurons’ responses to sound. Yet neurons are interconnected and interdependent, and cannot function in isolation from one another; rather, coordinated activity in small groups of neurons (called sub-networks, cell assemblies, or coordinated neural ensembles (cNEs)), is fundamental to information processing throughout the brain. Prior studies using calcium imaging have identified CNEs in primary auditory cortex, but the temporal resolution of calcium signals is poor compared to the precision and rapidity of auditory neural firing. Thus our understanding of how auditory neural ensembles are structured, how they relate to the dynamic sensory environment, and how they contribute to behavioral tasks, remains limited. Here, we combine high-channel-count electrophysiological techniques with optogenetics and behavioral studies to identify cNEs in awake mice, in order to answer fundamental questions about the basic properties and functional benefits of cNEs in the auditory system: how do specific cell types shape and segregate cNEs, how do cNEs influence information transmission from medial geniculate body (MGB) to primary auditory cortex and how does this differ between cell types, and how do cNEs change and function during learning and task performance.