We study how genes and neural circuits have evolved to generate new patterns of behavior. We have focused on the song that Drosophila (fruit fly) males “sing” by vibrating their wings. Each species sings a unique song, implying that the underlying neurophysiology has evolved rapidly, but the precise genetic and cellular changes driving novel behaviors remain largely unknown. We found that in two species that sing divergent songs, D. melanogaster and D. yakuba, homologous descending neurons respond to conserved social cues to drive different songs. Thus, neurons in the “pattern generating” circuit of the ventral nerve cord, downstream of the descending command, have evolved. This circuit is poorly understood, even in D. melanogaster, where a new EM volume provides a comprehensive view of the putative song circuit. We have therefore focused much of our recent effort on physiological studies of key neurons in this circuit, using a new prep that allows imaging of the ventral nerve cord during naturalistic singing. I will present key results from these studies and discuss how they are shaping our understanding of song circuit function. We are now building reagents to perform similar physiological measurements of homologous neurons in D. yakuba, which, together with this new prep, provides a path toward a deeper understanding of song circuit evolution.

Those wishing to meet the speaker should contact Nadeera M. Wickramasinghe, in the Mann Lab.

The Columbia Neuroscience Seminar series is a collaborative effort of Columbia's Zuckerman Institute, the Department of Neuroscience, the Doctoral Program in Neurobiology and Behavior and the Columbia Translational Neuroscience Initiative, and with support from the Kavli Institute for Brain Science.