Meeting Abstract
In their natural environments, fishes are faced with diverse flow patterns that require regular behavioral stabilization. Here, we investigate the behavioral responses to destabilization in fish and their mechanical and neural bases. We examined behavioral and physiological responses to pitch and roll in larval zebrafish. To generate roll, we developed two preparations in which the fish were either embedded in agar with the fins freed, or completely free in a small tank. We analyzed the kinematics of pectoral fin movements, and we measured the degree of roll, the angular velocity, and the angular acceleration of the animal. The fish exhibited consistent pectoral fin beating correlated with angular acceleration in the roll direction. The fin beat pattern resembled that of slow swimming, with either a synchronous or asynchronous first fin beat followed by alternating fin beating. We saw a higher incidence of asynchronous abduction in the initial beat than is typical of slow swimming. The duration of the first beat cycle remained consistent, and did not vary significantly with the strength of the stimulus. In contrast, zebrafish did not show a significant pectoral fin response to pitch movement in the embedded preparation. The lack of pectoral fin movement in response to pitch demonstrate that the pitch and roll neural circuits produce different motor output in larval zebrafish. To understand this, we examined the neurophysiology of the responses. In our previous work, cranial transections indicated that hindbrain input is sufficient to elicit this response. Calcium imaging in the hindbrain suggests some candidate regions in which the stimulus may be processed and converted into motor output.
