LE LIEU D’UNE “MISE EN FORME”: CORTICAL AND SUBCORTICAL CORRELATES OF AUDITORY PERCEPTION

Abstract

Improving discrimination of near-threshold auditory stimuli through training, also known as auditory perceptual learning, is a phenomenon which supports many complex behaviors such as animal communication, speech acquisition, language learning, and musical ability. Previous studies have highlighted the importance of certain frontal and sensory cortical areas in auditory perceptual learning, but we lack a complete understanding of the neural mechanisms involved. Here, we characterize the anatomical and physiological dynamics of relatively under-explored circuits in perceptual learning to improve our whole-brain understanding of the underlying neural processes. Using virally-mediated anatomical tracing techniques, we reveal the connectivity patterns of the orbitofrontal cortex to the auditory system in the Mongolian gerbil, a popular animal model for auditory studies. We use fiber photometry for projection-specific monitoring of corticofugal neurons, which reveals how this population exhibits non-monotonic sound sensitivity and sends nonsensory information to downstream targets during perceptual task engagement. Finally, we use multi-channel electrophysiological recordings to detail task-dependent and learning-related plasticity in sound-evoked activity at subcortical stations in the auditory pathway across perceptual learning. The findings from these experiments shed light on the circuitry supporting auditory perceptual learning and provide a more complete understanding of the neural mechanisms supporting this behavior.