P1 interneurons promote a persistent internal state that enhances inter-male aggression in Drosophila.

Eric D Hoopfer,Yonil Jung,Gerald M Rubin,Hidehiko K Inagaki,David J Anderson

doi:10.7554/elife.11346

Eric D Hoopfer, Yonil Jung + Show 3 more

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https://doi.org/10.7554/elife.11346

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Abstract

How brains are hardwired to produce aggressive behavior, and how aggression circuits are related to those that mediate courtship, is not well understood. A large-scale screen for aggression-promoting neurons in Drosophila identified several independent hits that enhanced both inter-male aggression and courtship. Genetic intersections revealed that 8-10 P1 interneurons, previously thought to exclusively control male courtship, were sufficient to promote fighting. Optogenetic experiments indicated that P1 activation could promote aggression at a threshold below that required for wing extension. P1 activation in the absence of wing extension triggered persistent aggression via an internal state that could endure for minutes. High-frequency P1 activation promoted wing extension and suppressed aggression during photostimulation, whereas aggression resumed and wing extension was inhibited following photostimulation offset. Thus, P1 neuron activation promotes a latent, internal state that facilitates aggression and courtship, and controls the overt expression of these social behaviors in a threshold-dependent, inverse manner.

Highlights

Aggression is an innate social behavior that is critical for survival and reproduction in most sexually propagating metazoan species (Lorenz, 1966)
We screened a large collection of GAL4 lines with molecularly defined enhancers (Pfeiffer et al, 2008; Jenett et al, 2012) that directed expression of the temperaturesensitive cation channel Drosophila TrpA1 (Hamada et al, 2008) in different populations of neurons
Multiple pairs of males for each genotype were screened in a high-throughput aggression assay (Asahina et al, 2014) using CADABRA software (Dankert et al, 2009) for automated scoring of aggressive behaviors as well as unilateral wing extension, a component of male courtship song

Summary

Introduction

Aggression is an innate social behavior that is critical for survival and reproduction in most sexually propagating metazoan species (Lorenz, 1966). The neurons responsible for this activity were identified in the murine ventromedial hypothalamus (VMH), using steroid hormone receptors as molecular markers, and optogenetics (Lin et al, 2011; Lee et al, 2014) or genetically targeted cell ablation (Yang et al, 2013; reviewed in Falkner and Lin, 2014; Kennedy et al, 2014) These cells number ~2,000 per hemisphere, they play a role in male-female mating behavior as well as in fighting (Lin et al, 2011; Sano et al, 2013; Yang et al, 2013; Lee et al, 2014).

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