A Neuronal Pathway that Commands Deceleration in Drosophila Larval Light-Avoidance
When facing a sudden danger or aversive condition while engaged in on-going forward motion, animals transiently slow down and make a turn to escape. The neural mechanisms underlying stimulation-induced deceleration in avoidance behavior are largely unknown. Here, we report that in Drosophila larvae, light-induced deceleration was commanded by a continuous neural pathway that included prothoracicotropic hormone neurons, eclosion hormone neurons, and tyrosine decarboxylase 2 motor neurons (the PET pathway). Inhibiting neurons in the PET pathway led to defects in light-avoidance due to insufficient deceleration and head casting. On the other hand, activation of PET pathway neurons specifically caused immediate deceleration in larval locomotion. Our findings reveal a neural substrate for the emergent deceleration response and provide a new understanding of the relationship between behavioral modules in animal avoidance responses.
KeywordsDrosophila Larva Deceleration Light avoidance EH neurons PTTH neurons Tdc2 motor neurons
We thank Mathieu Louis for sharing free SOS codes; Michael O’Cornor for PTTH-Gal4; Berni Jimena for tsh-Gal80; and Xiaohui Zhang, Chao Tong, Xiaohang Yang, Liming Wang, and Yijun Liu for sharing reagents and valuable discussions. We also thank the Bloomington Drosophila Stock Center and Qinghua Drosophila Stock Center for providing the fly stocks, and the core facilities of Zhejiang University School of Medicine for technical support. This work was supported by grants from the National Basic Research Development Program of China (973 Program, 2013CB945603), the National Natural Science Foundation of China (31070944, 31271147, 31471063, 31671074, and 61572433), the Natural Science Foundation of Zhejiang Province, China (LR13C090001 and LZ14F020002), and the Fundamental Research Funds for the Central Universities, China (2017FZA7003).
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Conflict of interest
The authors declare no competing interest.
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