FIGURE 2.

EEG response and dynamics during light exposure. (A,D,G,J,M; left column) Effect of light condition on each EEG band. EEG delta, theta, high alpha, beta and gamma absolute power densities are expressed relative to their respective dim light (min 0) values, in normalized units (n.u.). (B,E,H,K,N; middle column) Variation of EEG delta, theta, high alpha, beta, gamma during the protocol. Each pulse, corresponding to the average over the four light conditions, is shown in plain lines. Absolute EEG power densities for each band are expressed relative to their dim light level at 19:10, in normalized units (n.u.). Gray bars show the 10-min dim-light episode before each light exposure. (C,F,I,L,O; right column) Dynamics of the EEG during the 50-min light exposure. Absolute EEG power densities are expressed relative to their respective dim light (min 0) values, as normalized units (n.u.). Schematic representation of the light stimulus is shown above the time (min) axis. The gray circle indicates dim light. The blue- or red-enriched white light condition is illustrated by the blue circle. The yellow circle inside the blue circle represents the presence of the central light spot (C1 or C2) in addition to the full field exposure. The two vertical dotted lines indicate the light transitions, from dim light to blue- or red-enriched white light, and to addition of C1 or C2. Values represent the mean ± s.e.m. Dotted horizontal lines indicate the baseline dim-light level. #Significant pairwise comparison between min 0 and min 1. ^∗Significant pairwise comparisons between min 1–42 time-points. P-values of all post hoc pairwise time comparisons are given in Supplementary Table 2.