Seeds, Andrew, PhD

Our research addresses how the nervous system is organized to drive sequences of different movements. We study the grooming behavior of fruit flies because it consists of a stereotyped sequence of leg movements that clean the different body parts. The predictability of the movements provides a great behavioral readout for determining how manipulations to different parts of the nervous system change the behavior. Grooming is of general interest because the neural mechanisms that control sequential behavior are implicated in disorders whereby movements become overrepresented (e.g. obsessive-compulsive disorder). Therefore, we also examine how mutations in specific genes can impact grooming circuitry to understand the etiology of grooming-related disorders.

HOW IS THE GROOMING SEQUENCE ORGANIZED IN THE NERVOUS SYSTEM?

We use fruit flies for our research because of the cutting edge genetic tools that enable us to identify and manipulate the activity of neural circuitry that controls grooming. Using these tools, we test hypotheses about how the sequence is formed. The image below shows our current model that features independently evoked grooming movements that are activated in parallel by dust and selected serially through a hierarchical suppression mechanism.

WHAT NEURAL CIRCUITS DRIVE GROOMING BEHAVIOR?

We use a number of cutting-edge circuit mapping techniques to determine the neural implementations of the grooming sequence. Grooming movements feature highly stereotyped, and often repetitive movements that sweep across the body surface, yet the execution of these movements must be flexible to fulfill particular needs. For example, the grooming duration over which a particular movement is performed can vary in response to particular stimuli such as displacement of the body part, debris, or parasites. Therefore, we also examine grooming neural circuitry as a model for understanding how movements are selected and flexibly controlled.

HOW DO GENETIC DEFECTS CAUSE ABNORMALLY REPETITIVE BEHAVIORS?

Nervous systems produce produce complex sequential behaviors by sequentially selecting specific movements. Importantly, brain regions controlling this selection are implicated in disorders in which movements become abnormally repetitive, such as in obsessive-compulsive disorder (OCD). Because abnormally high levels of grooming occur in animals with mutations in specific genes, grooming may serve as a model of repetitive movement disorders. We combine our tools for studying grooming neural circuitry with the genetic amenability of fruit flies to study how mutations in specific genes can lead to abnormally repetitive grooming.