Figure 3.

(A) Scheme of the contextual fear-conditioning paradigm in Experiment 4 with training right before the onset of the active (dark) phase. Half of the animals were subjected to sleep deprivation (SD) for 12 h immediately following training; 24 h after training, animals were tested for contextual fear during a 5-min test phase. (B) Mean number and type of stimulations needed to keep the animals awake for 12 h during the entire dark phase. (C) Animals sleep deprived for 12 h (n = 20) during the dark phase displayed significantly less freezing behavior in response to the shocked context than did control animals (n = 19). Data are expressed as mean ± SEM. *P < 0.05.