Vocal learning in songbirds provides an attractive model system through which to study the neural mechanisms underlying behavior. Evidence from electrophysiological studies has shown that behavioral state is relevant to the regulation of auditory feedback, which is necessary for song learning and maintenance. Endogenous cholinergic release is able to modify the expression of auditory responses in a manner similar to that noted across behavioral states and selects between functionally distinct pathways in the song system. Our proposal aims to utilize in vitro electrophysiology to determine the effects of cholinergic tone on the network reconfiguration of a forebrain nucleus that is the nexus of premotor and auditory activity. While cholinergic mechanisms have been shown to be involved in sensory cortex reorganization, attention, arousal, and sensory modulation, the role of acetylcholine in sensorimotor processing is not well defined. The experiments proposed herein have the potential to illuminate the role of acetylcholine in network reconfiguration and sensorimotor processing in relation to an ethologically relevant learned motor behavior. ? ?