Meeting Abstract

103.2  Saturday, Jan. 7  Characterizing sensory nerve fiber responses to pectoral fin ray bending WILLIAMS IV, R.*; NEUBARTH, N. L.; HALE, M. E.; Univ. of Chicago; Univ. of Chicago; Univ. of Chicago rwilliams@uchicago.edu

While the roles of fins in actinopterygian locomotion have been studied in depth, little is known of how they receive sensory feedback from interactions with the physical environment. We selected the bluegill (Lepomis macrochirus), a species that uses its pectoral fins extensively during swimming, as a model organism for the exploration of pectoral fin somatosensation. Previously we demonstrated that the sensory nerves innervating the pectoral fins of bluegills are capable of conveying mechanosensory feedback in response to fin bending, using extracellular physiological recordings in a fictive fin preparation. In this study we examine the responses of these nerves to sinusoidal and step-and-hold bending of the fin rays. Activity recorded in response to these stimuli show that sensory nerve fibers respond to the magnitude and the velocity of the bending movement. Additionally, we used spike-sorting analyses to examine the responses of individual afferents to aspects of fin ray bending. These data suggest that there are multiple types of mechanosensory neurons responsive to fin ray bending and that these populations of neurons may communicate different properties of the bending stimulus. The feedback provided by these neurons may allow the pectoral fins to act as mechanical sensors as well as propulsors.