Meeting Abstract
Accurate sensory processing during movement requires the animal to distinguish between external and self-generated stimuli to maintain sensitivity to biologically relevant cues. Descending modulatory inputs from the brain have long been hypothesized to be a principle mechanism for filtering sensory reafference in the periphery via corollary discharge during muscle activation. The lateral line system in fishes is a mechanosensory organ that experiences sensory feedback via detection of self-generated fluid motion during swimming. We simultaneously monitored motor neuron commands and spontaneous lateral line afferent activity during and after swimming. Lateral line afferent activity was reduced during swimming, but was not fully inhibited in all cases. The attenuated spike frequency was sustained even after the offset of motor activity indicating the inhibitory control was not confined to the duration of the swim. This reduction in spike rate was substantial and only returned to intrinsic spontaneous spike rates after a well-defined refractory period. We quantified the anticipated influence the refractory period would have during the glide phase of intermittent burst-and-glide swimming behaviors. The relationship between the proportion of time the refractory period overlaps with the glide duration to tail-beat frequency and swim duration reveals that employing fast, short swimming strategies minimizes lateral line desensitization during the glide period. Our results detail a neuromodulatory mechanism in larval zebrafish that adaptively filters self-generated flow stimuli during both active and passive phases of locomotion.
