Research in the Polley lab is focused on the connection between neural circuit dynamics in the auditory cortex and the perception of sound. Projects in our lab address a broad portfolio of complementary basic science and applied research topics. Basic research projects leverage recent advances in two-photon calcium imaging, multi-channel electrophysiology, deep brain imaging and optogenetics to measure and manipulate neural circuits in awake, behaving mice. These studies place a particular emphasis on chronic imaging, activation or silencing of genetically identified cell types in the auditory cortex and basal forebrain while mice formulate, test and revise predictions about the contingencies between sounds and behavioral reinforcement. We perform these studies in adult mice with normal hearing or induced hearing loss to learn more about the mechanisms that enable and constrain plasticity and perception in the mature auditory system. Discoveries from our basic research projects directly inform our applied research projects in human subjects that cannot perceive the sounds they want to hear (e.g., speech in background noise) or cannot stop the perception of sounds they do not want to hear (e.g., tinnitus and hyperacusis). This work has lead us to develop new approaches to measure and rehabilitate auditory function in patients with debilitating perceptual disorders.