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Faculty Sponsor

Dr. Ryan Yoder

Department/Program

Department of Psychology

University Affiliation

Indiana University – Purdue University Fort Wayne

Abstract

Head direction cells appear to provide stable representations of directional heading that contribute to navigation. Damage to brain structures containing these cells has been shown to interfere with performance on spatial tasks. Indeed, surgical brain lesions to the postsubiculum have been found to impair radial maze performance, suggesting involvement of head direction cells in this task (Taube, Kesslak, & Cotman, 1992). However, these lesions10T o10Tften cause collateral damage and disrupt additional brain signals, and this10T c10Tollateral damage may underlie10T t10The observed spatial deficits. As a complementary approach, we evaluated the navigation ability of otoconia-deficient tilted mice, which have intact brains, but have degraded head direction signals. We therefore compared navigation between tilted mice and their control littermates on a landmark navigation task10T u10Tsing10T e10Txtramaze cues, and a cued navigation task using10T in10Ttramaze cues. Performance was quantified by10T t10The percentage of correct arm choices per trial, as well as the frequency of working memory-correct errors (re-entries into baited arms), reference memory errors (first entry into unbaited arms), and working memory-incorrect errors (re-entries into unbaited arms). The landmark navigation task indicated10T th10Tat control mice reached asymptotic performance near 90% correct arm choices by day 7, whereas tilted mice did not exceed 60% correct arm choices by day 10. In addition, reference memory and working memory-incorrect errors were more prevalent for tilted mice. On the cued navigation task, there were no significant differences between groups. The increased frequency of reference memory and working memory-incorrect errors in tilted mice performing the landmark navigation form of the radial arm maze suggests the head direction signal is involved in landmark navigation.

Disciplines

Psychology | Social and Behavioral Sciences

Head Direction Signal Contributes to Landmark Navigation on the Radial Arm Maze

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