CBE/ENGR 225 Faculty Seminar: Julie H. Simpson, Ph.D., Assistant Professor, Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara
Julie H. Simpson, Ph.D.
Assistant Professor, Department of Molecular, Cellular, and Developmental Biology
University of California, Santa Barbara
Tuesday, January 10, 2017
ESB, Room #2001
*Cookies and Coffee will be provided*
How Neural Circuits Achieve Sequential Action in Fly Grooming Behavior
Abstract: Animals can solve the problem of choosing between competing actions by executing behaviors in sequence. Fly grooming provides an opportunity to identify the neural circuits that compare sensory inputs and arbitrate among motor outputs to coordinate a flexible cleaning progression. Grooming is evoked by dust on the body surface and consists of individual cleaning movements targeted to body parts: head and front leg rubbing constitute an anterior motif, while abdominal, wing, or thoracic sweeps alternate with back leg rubbing make up posterior motifs. We use automated analysis of grooming movements to show that the brain affects the balance of grooming motifs and the anterior-to-posterior progression. The activation of mechanosensory bristle neurons evokes cleaning movements, but addition of dust increases time spent grooming, suggesting some contribution from other sensory modalities. Our screens for specific neuronal types that affect grooming reveal some that mediate between leg rubbing and body sweeps, and others that increase the probability of posterior motifs. We continue to search for neurons that control the flexibility and progression of this innate motor sequence using behavior quantification, optogenetic manipulation of neural activity, and functional imaging in candidate neurons. The identification of general circuit motifs that perform critical sensory comparisons and coordinate motor actions furthers our understanding of the computational building blocks used by all brains. Defining the neurons that regulate the flexibility and stereotypy of motor sequences will inform new approaches to treat human disorders characterized by abnormal sequences such as Parkinson’s disease and Obsessive Compulsive Disorder.