Tracking Information Flow in the Brain

The participants complete visual attention and perception tasks while fMRI, EEG, and MEG record brain signals. The tasks acquire responses with a visual saccade or button presses which are coupled to brain responses. These responses are then analyzed to identify patterns of communication between brain areas (within-subject). The flickering stimuli (experiment 1) may alter oscillations in the brain, while participants complete visual attention and perception tasks, leading to a secondary outcome measure distinct from the button presses. The procedure concerning the flickers will be the same for participants. The tACS (experiment 2) delivers input in addition to gathering output while participants complete visual attention and perception tasks. A sinusoidal current at a chosen frequency interacts with the brain's natural oscillations and alters responses. Participants will have sham sessions of tACS as well (there is no group division), The sham will be compared with the stimulation