Meeting Abstract
The ability of a moving animal to discriminate external stimuli from self-generated stimuli is important to maintain sensitivity to biologically relevant cues. The lateral line system allows fishes to detect changes in their fluid environment. The deflection of mechanosensory neuromasts by fluid motion results in an increased frequency of action potentials in the afferent neurons. Many studies have investigated the response properties of lateral line neuromasts and afferents, but to better understand the underlying physiological response of neuromast stimulation we must investigate afferent neuron activity in the context of the animal’s behavior. During swimming behavior, an efference copy of motor signals may function to modulate afferent activity. Using larval zebrafish (Danio rerio) of different ages (4-8 dpf), we quantified how the spontaneous frequency of afferent spikes was modulated during fictive swimming. To do this, we simultaneously recorded from afferent neurons and ventral motor root using extracellular recordings. Several motor activities were elicited (i.e. electrical and visual) and characterized, including swimming across frequencies from 20-50 Hz. During motor activity, afferent spontaneous activity decreased by 72.0%. This relationship was maintained across varying frequencies of motor activity. In addition, there was no significant change in modulation through development. This study suggests that the efferent system indiscriminately modulates the hair cells and/or afferent fibers to limit reafference during voluntary motion.
