Functional inactivation of dorsal hippocampus impairs active place avoidance in rats

This paper assesses the contribution of hippocampus to the spatial orientat ion of Long-Evans rats in a new place avoidance task. The animals learn to avoid a mild footshock in a segment of a rotating arena. Since the punished region is defined in the coordinate system of the stationary room the subj ect is forced to move away from the prohibited segment even if it is immobi le. After bilateral injection of tetrodotoxin (5 ng in 1 mu l of saline) in to the dorsal hippocampus rats were not able to avoid the punished place wh ile a similar injection of saline did not affect performance. The results s uggest the task is suitable for assessing the hippocampus-dependent spatial abilities of laboratory rodents. (C) 2000 Elsevier Science Ireland Ltd. Al l rights reserved.