Figure 7.

Tracking of a rat searching pellets on a slowly moving (one revolution per 30 s) circular arena (1 m diameter) before (A) and during (B) acquisition of the place avoidance induced by electric foot shocks applied whenever the animal enters a southeast region of the floor (marked by the heavy semicircular line). Length, total length of the track; time, total recording time. The numbers in the corners indicate the percentage of track length and track time corresponding to four equal semicircular regions in northeast, southeast, southwest, and northwest. The lower curves show the rat’s distance from the center of the shock region during the 10-min recording, with the critical radius indicated by the heavy horizontal line. The vertical lines indicate 1-min intervals. Note that all regions were equally visited before electrical stimulation in A and that the shock region was avoided after the two shocks received in the first and second minute of exploration in B.