Figure 4
Effect of visual stimulation with 10-ms 620-nm light pulses at 0.6 Hz on EEG power spectrum. The profile of spectral power over 24 h was compared between the baseline day and the next day during which the visual stimulation was performed. The profile of spectral power in mice stimulated with 400-ms light pulses during wakefulness (A), NREM sleep (B) and REM sleep (C) is similar to that observed in the mice stimulated with 400-ms light pulses (Fig. 2), except that the amplitude of both the fundamental frequency and harmonics is lower. EEG power in the stimulation frequency range (0.49–0.61 Hz) and delta frequency range (0.49–4.52 Hz) were not statistically different between baseline and in the process of the light stimulation during wakefulness (D) and NREM sleep (E) but was higher during REM sleep (F). *p < 0.05.
