Ed Kravitz, PhD

Olga Alekseyenko, PhD

David Bochner

Sarah Certel, PhD

Yick-Bun Chan, PhD

Adelaine Leung, PhD

Jill Penn, PhD

Joanne Yew, PhD

Sarah Certel, Ph.D.

Post-doctoral Fellow

Email: sarah_certel@hms.harvard.edu

Tel: 617-432-1042

I’m a postdoctoral fellow in the Kravitz lab. My research focuses on understanding how complex behavioral programs are organized and modulated in the nervous system. I am currently using Drosophila as a model system to molecularly and anatomically characterize how the circuits directing the innate social behaviors of aggression and courtship are built and function. Aggression and courtship provide excellent models to dissect the neural substrates of complex behavioral outputs. The indispensable characteristics of these behaviors include: (i) elaborate stereotyped behavior patterns, (ii) behavioral patterns modified by experience (i.e. learning and memory), (iii) sex-specific patterns of behavior, (iv) behavioral output mediated by multi-sensory environmental cues, and (v) mutually exclusive traits leading to studies of behavioral choice. In addition because aggression and courtship are usually mutually exclusive traits, they provide a system to examine how context-specific sensory information is detected and integrated to identify distinct ethological contexts.

In a recently completed work, we manipulated both the activity and sex of a very small subset of neurons and found significant changes in the aggression versus courtship choices of Drosophila males (Certel et al, 2007). Results from our aggression assays indicate that the neuromodulator octopamine is necessary for males to coordinate sensory information presented by a second male and respond with the appropriate behavior, aggression rather than courtship. In competitive male courtship assays, males with no octopamine or low levels of octopamine do not adapt to changing sensory cues and court both males and females. We also demonstrated that feminizing octopamine neurons in an otherwise masculine CNS changes the aggression versus courtship response behavior. Since aggression vs courtship behavioral responses are predominantly male-specific choices, I asked how the subcircuits involved might be programmed in the nervous system. I identified a small subset of neurons in the suboesophageal ganglion (SOG) region of the adult male brain that co-express octopamine and the male forms of the neural sex determination factor, Fruitless (FruM).

My current work and future aims continue to center on understanding how sensory information is processed and integrated into the nervous system, and second, using brain structure and function to understand the neural basis of aggression. These research aims take a multi-disciplinary approach encompassing developmental, genetic, and behavioral techniques using the strength of Drosophila as a model organism.

Recent Publications: