A Brain Module for Scalable Control of Complex, Multi-motor Threat Displays
Threat displays are a universal feature of agonistic interactions. Whether threats are part of a continuum of aggressive behaviors or separately controlled remains unclear. We analyze threats in Drosophila and show they are triggered by male cues and visual motion, and comprised of multiple motor elements that can be flexibly combined. We isolate a cluster of ∼3 neurons whose activity is necessary for threat displays but not for other aggressive behaviors, and whose artificial activation suffices to evoke naturalistic threats in solitary flies, suggesting that the neural control of threats is modular with respect to other aggressive behaviors. Artificially evoked threats suffice to repel opponents from a resource in the absence of contact aggression. Depending on its level of artificial activation, this neural threat module can evoke different motor elements in a threshold-dependent manner. Such scalable modules may represent fundamental "building blocks" of neural circuits that mediate complex multi-motor behaviors.
© 2018 Elsevier Inc. Received 19 May 2018, Revised 11 September 2018, Accepted 16 October 2018, Available online 8 November 2018. We thank Gerry Rubin for sharing unpublished reagents (see Key Resources Table); Talmo Pereira for classification code; Kiichi Watanabe for performing the experiments in Figure S7E; Hidehiko Inagaki for sharing R21B10-FLP; Jon Schor, Ruohan Wang, Alberto Corona, Michael Altermatt, and Jared Everson (students) and Yonil Jung, Peter Weir, Michael Dickinson, Mhemet Keles, and Mark Frye for help with Ca^(2+) imaging experiments; Kavya Sreedhar, Luciana Hartmann, Romann Webber, and Yisong Yue for assistance with transition diagrams; Evan Tanner for SV1 code; Ana Silbering and Richard Benton for quad olfactory mutants; Barry Dickson for FruM anti-body; and Anderson lab members who provided expertise and comments. B.J.D. was a Life Sciences Research Foundation fellow for the Ellison Medical Foundation. D.J.A. is an Investigator of the Howard Hughes Medical Institute and supported by NIH grant #DA031389. Author Contributions: D.J.A. and B.J.D. conceived the project, designed experiments and interpreted the results. B.J.D. conducted experiments, made figures, and with D.J.A. co-wrote the manuscript. B.D.P. provided reagents and expertise. E.H. originally identified and provided advanced access to R20E08 and Split Gal4s. The authors declare no competing interests.
Accepted Version - nihms-1511838.pdf
Supplemental Material - 1-s2.0-S0896627318309358-mmc1.pdf