Title

Otolith Dysfunction Impairs Dead Reckoning in Mice

Document Type

Poster Session

Presentation Date

11-19-2014

Conference Name

2014 Neuroscience Meeting Planner

Conference Location

Washington, DC: Society for Neuroscience

Abstract

Program No. 848.11/UU26

Navigation in non-visual environments is impaired by damage to the vestibular system. However, no studies have tested whether the critical vestibular signals originate in the semicircular canals, which detect angular head acceleration, or the otolith organs, which detect linear head acceleration and static pitch/tilt relative to gravity. We therefore evaluated the navigation performance in otoconia-deficient tilted mice and their littermate controls on a food-hoarding task. In light, food-restricted mice were trained to exit a start box in search of a single food item, and to carry the food directly back to the visible start box for consumption. After training was complete, a test phase was conducted in darkness, forcing animals to rely on idiothetic cues (e.g., proprioception, motor efference copy, vestibular) experienced during the outward journey in order to return directly to the start box. Motion capture software was used to quantify movement characteristics during a food hoarding trip. Each trip was divided into outward (i.e., departing the refuge to locating the food item) and homeward (i.e., locating the food item to contacting the refuge) components. Groups did not differ in outward segment path circuity, peak speed, or movement segmentation. However, the homeward segment for control mice was relatively direct, whereas the homeward journey for tilted mice was significantly more circuitous. These results suggest the otolith organs contribute to dead reckoning in darkness.

Keywords

Vestibular, Navigation

Disciplines

Psychology

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