New Orleans, LA
Head direction cells provide a stable representation of directional heading that may contribute to accurate spatial learning, as indicated by impaired radial arm maze performance after damage to the ascending head direction cell circuit. However, brain lesions often produce collateral damage, and the loss of other brain signals could underlie the spatial deficits. We therefore tested whether the head direction signal contributes to spatial learning by evaluating the radial maze performance of otoconia-deficient tilted mice, which have degraded head direction signals but no other known deficits. Homozygous tilted mice and their heterozygous control littermates performed a six-arm radial maze discrimination task where the same two arms were baited for four trials per day, across ten days. Control mice made >80% correct arm choices by the seventh day of training, whereas tilted mice improved across days but did not exceed 65% correct choices by the tenth day of training. The performance deficit in tilted mice was influenced by working memory and reference memory errors, both of which were more frequent in tilted mice than in control mice. These preliminary results suggest that head direction signal integrity is related to radial arm maze performance.
Seth L. Kirby and Ryan M. Yoder (2012).
Impaired spatial learning in otoconia-deficient mice. Presented at Neuroscience 2012, New Orleans, LA.