Meeting Abstract
In stress disorders such as PTSD, chronic exposure to a threat stimulus results in sensitization or hypervigilance. Much remains unknown about the neurophysiological mechanisms underlying this phenomenon. The genetic tools and robust startle response of the zebrafish make it a tractable model to study the molecular basis of stress-induced behavioral changes. In zebrafish, the lateral line is a structure containing hair cells, sensory receptors that allow the fish to sense the flow of surrounding water. This mediates a startle response wherein a hydrodynamic stimulus is perceived as a threat. The startle response behavior demonstrates an intensity-dependent relationship where the magnitude of the stimulus and latency of response are inversely related. This project aims to explore how the established relationship between the intensity of stimulus and latency is affected by chronic stimulation of the lateral line during early larval development. To test this paradigm, we used transgenic zebrafish containing blue light-sensitive channelrhodopsin-2 (ChR2) in hair cells of the lateral line. Administration of blue light stimulus allowed for remote activation of the lateral line via depolarization of hair cells mediated by ChR2. The latency and probability of startle response were recorded using a high-speed camera. The data showed no significant relationship between the intensity of stimulus and response latency or probability, though significant improvements can be made in experimental design. Although results from this study were inconclusive, further study may indicate a level of developmental neuroplasticity in the mechanosensory system of larval zebrafish and illuminate the neural mechanisms underlying stress-related behavioral response.
