Figure 6. Average ECoG spectral profiles for each behavioral state recorded during 2 d under standard LD 12∶12 conditions.

Power density in the theta and gamma frequency ranges was generally higher and in the delta frequencies lower (during NREM sleep) in Opn4^−/− mice. Insets: relative spectral changes quantified as log₂ of the ratio between Opn4^−/− (KO) and Opn4^+/+ (WT) power density values (e.g., 1 signifies a two-fold increase). Line segments in red denote significant genotype differences (p<0.05; post hoc t-tests; n = 9/genotype). N, NREM sleep; R, REM sleep; W, wakfulness.