Fig. 2
From: Light-based gamma entrainment with novel invisible spectral flicker stimuli
Experimental Designs: Experiment A (top) included four different types of light stimulus (ISF, CF, LF, and CON) at three levels of brightness. (Brightness is not illustrated in the figure). Each stimulus was presented six times and the order was randomized. An interstimulus interval (ISI) of five seconds was introduced between each stimulus. 60 seconds baseline with eyes-open and no light was also recorded at the beginning and the end of the experiment. EEG was recorded during the experiment. Experiment B (middle) included light stimulation with ISF. Participants were asked to gaze at different fixation points only once in each of the two blocks. The order within each block was random. The light stimulus was turned on for 60 seconds, followed by 20 second ISI to allow for verbal instructions on the next fixation point. EEG was recorded during the experiment. Experiment C (bottom) included the same 12 light stimuli as experiment A, however, participants would rate each of the stimuli in terms of perceived discomfort and flicker. Each stimulus was presented four times in random order. The stimulus would change when rating was completed, and pace of the experiment was thereby controlled by the participant.
