Meeting Abstract

58.3  Sunday, Jan. 5 14:00  Sensory and Motor Responses to Deflection of Single Neuromasts in the Lateral Line System in Larval Zebrafish LIAO, J.C.*; AKANYETI, O; BALLO, A; HAEHNEL, M; LEVI, R; The Whitney Lab for Marine Bioscience/U. Florida jliao@whitney.ufl.edu

Larval zebrafish ( Danio rerio ) are able to use their lateral line system to detect flow-related information. To characterize the system, we performed electrophysiological recordings of posterior lateral line afferent neurons while deflecting individual neuromasts with a piezoelectric stimulator. We applied three distinct stimuli: a single deflection to look at the response to variations in deflection velocity (0.01 – 30 μm ms^-1), pure sine waves to test which frequencies (1 – 90 Hz) to which cells were most tuned, and a pulse that contained a broad frequency spectrum to quantify the ability of cells to transmit information at various frequencies. For single deflections, we found that maximum spike rate increased with stimulation velocity, while the time delay between stimulus onset and maximum spike rate decayed exponentially as a function of velocity. For sine wave stimuli, we used firing rate and vector strength to characterize responses across frequency and found mainly one type of cell with band-pass qualities, although we did record several cells that exhibited high and low-pass qualities. For pulse stimuli, we found that spiking rate did not increase linearly with stimulation frequency. Rather, as stimulation frequency increased, cells transitioned from phase-locking with spontaneous activity to only phase locking, and finally to a decreased ability to phase lock. Cells with higher spontaneous firing rates showed a corresponding sensitivity to higher stimulus frequencies. Remarkably, we could elicit fictive swimming with 50 – 85% probability with a single deflection of an individual neuromast, revealing a surprising sensitivity. Our findings advance our understanding of the neuronal mechanisms that enable fish to their lateral line system to convert mechanical stimuli into motor behaviors.