Investigating Auditory-Motor Interactions During Rhythm Perception in a Small Animal Model - ABSTRACT Much of the world’s music has periodic rhythms with events repeating regularly in time, to which people clap, move, and sing. The ability to detect and predict periodic auditory rhythms is central to the positive effects of music-based therapies on a variety of neurological disorders, including improving phonological processing in dyslexia, enhancing language recovery after stroke, and normalizing gait in Parkinson’s disease. Yet the neural mechanisms underlying rhythm perception are not well understood, and progress is impeded by the lack of an animal model that allows precise measurement and manipulation of neural circuits during rhythm perception. Human neuroimaging studies indicate that perceiving periodic musical rhythms strongly engages the motor planning system, including premotor cortex and basal ganglia, even when the listener is not moving or preparing to move. Here, we test the hypothesis that the motor planning system is actively involved in learning to recognize temporal periodicity and communicates predictions about the timing of periodic events to the auditory system. We propose to take advantage of the well-described auditory-motor circuits in vocal learning songbirds and leverage the mechanistic studies possible in an animal model to test these ideas. Like humans (and unlike non- human primates), vocal learning birds have strong connections between motor planning regions and auditory regions due to their reliance on complex, learned vocal sequences for communication. Auditory-motor circuits in songbirds and humans have many structural and functional parallels. Recently, we showed that songbirds can readily learn to recognize a fundamental periodic pattern (isochrony, or equal timing between events) and can detect this pattern across a broad range of tempi. In Aim 1, we will test whether neural signals from premotor regions play a causal role in this ability to flexibly recognize periodic rhythms. In Aim 2, by recording in auditory cortex while reversibly silencing activity in a reciprocally connected premotor region, we will test whether premotor signals influence auditory processing of periodic rhythms. In Aim 3, by recording activity in a premotor region as birds learn to recognize isochrony as a global temporal pattern, we will determine whether premotor neurons develop sensitivity to temporal regularity and exhibit activity that predicts the timing of upcoming events. Establishing an animal model for rhythm perception will be transformative for music neuroscience, allowing detailed investigation of the neural mechanisms underlying rhythm perception and informing rhythm-based musical interventions to enhance function in normal and disease states.
