Optogenetic Interrogation of the Neural Circuitry Underlying Courtship Song Patterning in Drosophila melanogaster

Abstract

The Drosophila melanogaster mating ritual involves the production of a courtship song consisting of unilateral wing extension and vibration. The song pathway has been heavily researched, and while several neurons are known to be involved in it, their specific roles in modulating certain aspects of courtship song have not yet been confirmed. In this project I used red-activatable channelrhodopsin (ReaChR) to study the relationships between neuronal stimulation of different stages of the song pathway (P1, pIP10, vPR6) and the pattern of song produced. This paper shows that the amount of song produced is positively correlated with stimulus intensity, frequency, and pulse width. For all three neuronal groups, increasing intensity leads to increased pulse amplitude; for vPR6 neurons, increasing frequency and pulse width also lead to higher amplitudes. In addition, vPR6 is the only neuronal group tested whose activation modulates the inter-pulse interval (IPI). All three genotypes produce time-locked song that occurs only during the stimulus presentation. Reliability tests confirm the correlation between stimulus intensity and song patterning of vPR6 flies.