Spatial learning is impaired in the water maze after 24 h of SI. (A) Mean (± SEM) distance to reach the hidden platform for three blocks of four acquisition trials (SI, sleep interruption; n = 11; EC, n = 10; CC, n = 11). Overall, SI rats took a significantly longer path to reach the hidden platform than did CC (P < 0.05), while EC rats were not significantly different from either group (P > 0.05). A probe trial was given 30 min after the last acquisition trial (see text for details). (B) The mean percentage (+ SEM) of total distance travelled in the target quadrant that formerly contained the hidden platform in a single 30-s probe trial given 30 min after the last acquisition trial. SI rats swam significantly less distance in the target quadrant than did CC (P < 0.05), but EC rats were not significantly different from either group (P > 0.05). Asterisk indicates P < 0.05.