Figure 7.

Effects of 45 min versus 15 min fear extinction training on P-wave density during REM sleep. These effects were observed during the 6 h sleep—wake recording period that immediately followed fear extinction training. Note that 45 min of training significantly increased P-wave density in some rats (Ext, n = 8) but significantly decreased P-wave density in other rats (Failed-ext, n = 6). Also note the significantly higher level of P-wave density in Ext rats compared with No-ext rats (n = 8). Error bars represent SEM; *p < 0.05, **p < 0.01, ***p < 0.001.