Place navigation in rats guided by a vestibular and kinesthetic orienting gradient

The role of the slope of terrain in orientation was examined in rats traine d to find, among 4 equidistant feeders, the 1 located in the upper left qua drant of a 10% tilted arena (l-m radius). Rats started from the center in l ight and with randomly changing slope direction reached the correct goal in 90% of Ist choices after 29 sessions. The same rats maintained 83% correct choices when the experiment was conducted in darkness. On a horizontal are na, their performance became random. After training, successful navigation was also observed (71% correct Ist choices) when the rats were started from different points at about 30 cm from the wall. This finding suggests that the slope of terrain may be used to establish a cognitive map based primari ly on kinesthetic and vestibular signals. The flexibility of such a map see ms to be rather limited, however, because changing the goal position with r espect to inclination requires prolonged retraining.