EEG spectra during slow-wave sleep stages. Effects of chronic SSRI treatment, 72 h of REM sleep deprivation and their combination on the power density of theta (5-9 hz) and alpha (10-13 hz) frequencies during light slow-wave sleep (SWS-1) and on theta frequencies during deep slow-wave sleep (SWS-2). Each point represents mean ± SEM values of 1-Hz bins in a 2 h recording period of 6-7 animals. *p < 0.05, **p < 0.01 and ***p < 0.05 mean significant post hoc effects of RD-VEH group compared to the HC-VEH group; #p < 0.05, ##p < 0.01 and ###p < 0.001 mean significant post hoc effects of RD-VEH group compared to HC-SSRI group, and & p < 0.05 represents significant post hoc effect of RD-SSRI group compared to RD-VEH group. Groups: home cage plus chronic vehicle treatment (HC-VEH); home cage plus chronic escitalopram treatment (HC-SSRI); REM sleep deprivation plus chronic vehicle treatment (RD-VEH); REM sleep deprivation plus chronic escitalopram treatment (RD-SSRI).