Meeting Abstract
37.6 Monday, Jan. 5 Sensory input for routine turns in larval zebrafish DANOS, Nicole; Harvard University ndanos@oeb.harvard.edu
Early locomotor behavior in zebrafish is highly stereotyped. In this study, I investigate the effects of the physical environment on the development of this early locomotor behavior. Specifically, I seek to determine which aspects of normal behaviors are controlled by sensory input and which by the hydrodynamic environment. Specifically, if fish are raised in an altered environment, one of higher viscosity, do they still perform the same behaviors? If so, do they still perform them in the same manner? What aspects of turning remain unchanged despite having raised the fish in a novel environment? Such aspects are likely independent of mechanical sensory input and are instead under tight sensory neural control. Moreover the sensory input for these turning variables is unlikely to be mechanical. Conversely, what aspects of turning scale with viscosity, suggesting less active neural control of the magnitude of such variables? To address these questions, zebrafish were raised in high viscosity (5, 10 or 15cP) until 5 days post fertilization. Five fish from each viscosity treatment were then filmed at 1000 fps performing at least three routine turns in the medium that they were raised in. The following turn characteristics were unaffected by viscosity and did not require any learning on behalf of the larvae since the fish never swam in normal viscosity water: maximum turn angle (o) and absolute duration (ms) of stage 2. The proportion of a turn spent in stage 1 also remained constant in all viscosity treatments, despite the absence of a strong correlation between viscosity and total turn duration. Maximum angular velocity decreased with viscosity only in 5 and 10cP; at 15cP it was indistinguishable from angular velocity in water. This experimental system allows for the distinction between hydrodynamic and neural control of normal behaviors such as routine turns and suggests that routine turns are largely under neural rather than hydrodynamic control.
