Meeting Abstract

P1.106  Tuesday, Jan. 4  Two distinct escape responses in the larval zebrafish, the C-start and S-start, show variability in a well-studied behavior LIU, Y.-C.*; BAILEY, I.; HALE, M. E.; Univ. Chicago; Univ. Chicago; Univ. Chicago ycliu@uchicago.edu

Startle responses are crucial to the survival of predatory attacks. In fishes, the most common startle response is the Mauthner neuron-initiated C-start. C-starts are characterized by a C-shaped body bend during stage 1, the initial rapid turn away from a threatening stimulus. Recent studies have shown that elongate esocid fishes (pikes and muskies) perform S-starts in addition to C-starts. In contrast to the C-start, during the S-start the fish performs an S-shaped bend during stage 1 of the behavior. With this work, we aimed to examine whether the S-start is a more common escape behavior, not limited to esocids. Specifically, we used the larval zebrafish’s accessibility as a model organism to investigate the startle motor pattern and behavior. We recorded the startle behavior of larval zebrafish at 5 dpf using high-speed video. We also recorded neural activity in response to startle stimulation from ventral roots at three locations along the body. In both behavior and physiology experiments we used head- and tail-directed stimuli to generate a range of startle movements and motor patterns. In many trials, an S-shaped bend of the body was observed during stage 1 of the escape behavior. Ventral root recordings demonstrated motor patterns characteristic of S-starts, with rostral muscle activity on one side of the body and near-simultaneous caudal muscle activity on the other. These data indicate that zebrafish have at least two discretely different startle behaviors, the C-start and the S-start. Furthermore, it shows that the S-start is not specific to esocid fishes and suggests that the behavior occurs over a much broader taxonomic diversity of fishes. Supported by NSF IOB0818788.