Audiomotor activity in the superior colliculus of the big brown bat engaged in a natural, acoustic orientation task

Abstract

To accurately select and orient to a target, noisy, and multimodal sensory information about the target’s location must be integrated into a coordinated set of orienting movements. At the hub of sensorimotor integration for species-specific orientation is the superior colliculus (SC), a midbrain structure receiving multimodal sensory inputs and projecting to premotor nuclei throughout the brainstem. Our research brings together behavioral and chronic neural recording data to examine auditory and premotor activity in the SC of the echolocating big brown bat as it performs a natural, goal-directed task. We trained bats to rest on a platform and track a tethered insect moved by a computerized stepper motor system. While the bat was tracking and capturing insects, single neuron activity was recorded across superficial, intermediate, and deep layers of the SC. Neural activity across the laminae of the SC signal auditory and pre-motor events: Echoes reflected from the sonar target evoked activity in superficial and intermediate layers, while premotor activity related to pinna, head, and vocal-motor behaviors was found at deeper recording sites. Collectively, the results of this study contribute to a deeper understanding of midbrain audiomotor activity in the context of natural goal-directed tasks.