Martha Bagnall Research Abstract

Awake animals normally maintain a particular orientation with respect to gravity. This feature of behavior is so fundamental that it's ingrained in our language: we refer to a failed business as going “belly up.” Posture is intimately dependent on signals from the inner ear, but we understand very little about how that information is mapped onto motor outputs. Our lab studies how sensory information about orientation and movement drives appropriate body movements to adjust posture.

To understand how animals maintain posture, we study the vestibulospinal system of the larval zebrafish. Vestibular neurons in the brainstem report an animal's movement and orientation with respect to gravity. A subset of them project to the spinal cord. What happens to the signals they carry? The spinal cord is home to a wealth of neuron types, which we can visualize and manipulate easily with transgenic zebrafish lines. Our lab is using a combination of electrophysiology, imaging, genetic manipulation, and behavioral analysis to identify how sensory signals about head orientation are mapped onto spinal circuitry to drive appropriate behaviors.

We are also interested in understanding how locomotor planning influences vestibular circuits. Many vestibular neurons receive direct input from the cerebellum, a motor planning structure. However, we know very little about the functional signals carried by the cerebellum. We can take advantage of the transparency of the larval zebrafish to watch cerebellar development dynamically over the critical period, and ask how it affects vestibular signaling during both quiescence and locomotion.