Even if you?re not a musical genius, each and every one of us is still a highly acoustic person. Speech and music are the most obvious sounds we make. But almost every other movement we make produces sounds, too (typing, walking, chewing, shutting a car door). In fact, navigating the world requires us to be able to detect, recognize, and predict the sounds of our own actions. The fact that we don?t notice most of the sounds we make speaks wonders to how well our brains can predict them in the first place. Malfunctioning of the same brain circuitry that normally anticipates the sounds of our actions has been implicated and disorders including tinnitus and schizophrenia. Understanding how the brain learns to anticipate the sounds of our actions is therefore key to understanding brain function during both health and disease. This proposal describes experiments aimed at understanding how auditory and motor systems interact during sound generating behaviors to anticipate the sounds our movements make. The experiments outlined in this proposal incorporate a host of innovative techniques. These include closed-loop augmented reality, large scale physiological recordings during behavior, calcium imaging, and optogenetics. The results of these experiments will help us understand how circuits of neurons within the brain learn to anticipate the sounds our movements make. The significance of the proposed research to the NIH mission is four-fold. First, this research can inform how the nervous system mediates normal hearing during sound-generating movements, which is essential to speech comprehension and learning, among other skilled, auditory-guided behaviors (e.g. musicianship). Second, dysfunction of this motor to auditory interaction at the cortical level is thought to drive auditory hallucinations in diseases including tinnitus and schizophrenia; characterizing motor-auditory interactions is a necessary step to understand the genesis of these pathologies and to ultimately design appropriate therapies. Third, an understanding of how motor-auditory circuits change with experience may provide insights into how these circuits can be manipulated either through perceptual training or direct manipulation of neural activity to facilitate auditory comprehension in the face of hearing loss.
The ability to predict the sensory consequences of our actions is critical for learning and maintaining many complex behaviors, including speech, as well as for normal hearing in everyday life. This proposal will investigate the neural circuitry necessary for learning to predict the anticipate and suppress the excepted acoustic consequences of our actions. This research will provide critical insights into brain mechanisms important for normal hearing and will form the basis for understanding how the brain processes phantom sounds in disorders including tinnitus and schizophrenia.
