Figure 1.

(A) In this experiment, male rats were exposed to an acute stressful event, and 24 hr later, tested on performance in the 8-arm radial maze task (Shors and Dryver 1992). The graph depicts the number of errors described as reentries into an arm that had previously been debaited. On the first few days of training, stressed rats committed fewer errors than unstressed rats, but with continued training, stressed rats committed more errors and the unstressed committed fewer. (B) The second graph depicts the activity of stressed and unstressed rats, defined as the arms entered per minute. Those exposed to the stressor were less active than those not exposed to the stressor, especially during the first few days of training. Overall, the data suggest that stress impedes, but does not necessarily impair spatial learning.