UC Berkeley

Understanding how neural circuits control complex social and spatial behaviors in humans requires a tractable mammalian model system that allows one to probe both the appropriate behavior and its underlying neural activity. Egyptian fruit bats (Rousettus aegyptiacus) are an attractive model for studying the motor control of vocal communication and navigation. To thrive within hierarchical social structures in dark cave environments, bats evolved specialized auditory and vocal production systems to both echolocate and communicate with one another. However, to date, the detailed neural computations that support this behavior in mammals are unknown. Furthermore, in the wild, bats fly highly reproducible trajectories from their home cave to foraging sites over 20km round trip nightly. It is unclear whether the neural representation of these flight paths remains stable across days when a stable behavior is performed. In this thesis, I describe my efforts to study the behavior, anatomy, and neurophysiology of vocal communication and spatial navigation in a novel model organism.

In Chapter 1, I provide and introduction to theories of vocal learning, mammalian motor control of vocal production, and social communication. Furthermore, I provide a focused review of the hippocampal representation of place and current theories of how this representation changes across days. In Chapter 2, I present my efforts to design a behavioral task that operantly trained the bats to produce vocalizations for reward. Additionally, I present anatomical tracing data that identified the motor cortical site of laryngeal control and supports the theory of vocal learning in bats. Finally, I discuss collaborations to probe the underlying electrophysiology in this motor region during the vocal production task. In Chapter 3, I present my work developing a wireless miniature fluorescent microscope and its use to study the longitudinal stability of spatial coding in freely flying bats performing a self-paced navigation task. This work is presented as a manuscript (currently under review) with my co-author Dr. William Liberti.