Four hours of paradoxical sleep deprivation impairs alternation performance in a water maze in the rat

Sixteen rats were deprived of paradoxical sleep (PS) for 4 h using the "flower pot" technique and 16 other served as yoked controls. PS-deprived and control rats then had to learn a water maze using either a standard allocentric configuration (i.e., finding the submerged platform using external cues; n = 6/group) or an alternation version (goal platform alternating between two locations; n 10/group). Rats were submitted to six trials with a cutoff time of 60 s and an intertrial interval of 5 min. Criterion was set as two consecutive successful completions. PS-deprived rats made more quadrant entries and took more time to reach criterion on the alternation task than control rats while both groups were equal on the allocentric task. Based on lesion studies (Ethier et al., this issue) we propose that tasks that require an intact medial prefrontal cortex are particularly sensitive to PS deprivation.