Figure 5.

Effects of chronic sleep deprivation (SD) on learning and memory of adolescent and adult rats in Morris water maze test (WMT). (A) The latency of rats swimming to find the platform. (B) The distance to reach the platform. Open and filled bars show the profiles before 1st sleep deprivation and the effects after different days of sleep deprivation, respectively. On day 1, the first training day, without sleep deprivation, there were no differences in performance between different groups. Similar results showed on day 2 (sleep deprivation day 1) and day 3 (sleep deprivation day 2), while on day 8 (sleep deprivation day 7), a significant difference was observed between the groups of sleep deprivation for 4 h and control in adolescents. (C-F) Swimming tracks of adolescent (F) and adult (D) rats after sleep deprivation for 7 days versus their control (E, C) rats in WMT. The small circle represents the platform that was submerged below the surface of the water. (G) Swimming speed of rats in WMT. There was no difference between the sleep deprivation and that of the control groups. (H-J) Memory was assessed on a probe trial in the absence of the platform on the 8th day, 7 days after sleep deprivation. The sleep-restricted adolescent rats tended to generate shorter path length and spend less time in the target quadrant, and made fewer platform crossings than rats in the control group. However, there were no significant differences between the sleep-restricted adult rats and the control rats in the probe trial. Values are mean ± standard error (n = 6-9). *P < 0.05, as assessed by t test.