Meeting Abstract

72.7  Monday, Jan. 6 09:30  During closed-loop refuge tracking, Eigenmannia virescens tunes its active sensing behavior to the length and features of the moving refuge STAMPER, SA*; PLOCH, C; FORTUNE, ES; COWAN, NJ; Johns Hopkins Univ; Hope College; New Jersey Institute of Tech; Johns Hopkins Univ sstamper@jhu.edu

Weakly electric fish seek shelter and will swim to maintain their position within a moving refuge. This ‘refuge tracking’ behavior is thought to be an image stabilization task in which the fish swims to maintain the sensory image of the refuge on its sensorium — retina and skin. However, other strategies may be used in the control of this behavior. For example, when tracking in the dark, fish generate ancillary whole-body oscillations as a form of active sensing, but clearly these movements do not stabilize the image. To better understand the sensory strategies used for refuge tracking, we examined how the length of the refuge and features (presence/absence of windows in the side walls) modulate tracking performance. We also examined active sensing strategies in both light and dark conditions. We found that tracking performance was improved for shorter refuges (less than a body length) and degraded for longer ones (greater than 1.5 body lengths). We found that the magnitude of active movements was dependent on the sensory condition and a combination of refuge length and features. When fish tracked the longest refuge, there was a significant increase in whole-body oscillations, especially when the refuge did not have ‘windows.’ Further, our analyses suggest that for longer refuges, the fish may not be simply tracking the refuge, but rather avoiding exiting the ends of the refuge. These data suggest that fish tune their active sensing regime depending on the features of the refuge in order to match the properties of electrosensory processing by neural circuits.