Subcortical Arousal in Perceptual Awareness

Participants will have scalp EEG recorded with the international 10-20 system sampled at 256Hz using EEG amplifiers for purposes of surface event related potential analysis

An eye-tracking device may be used during the perceptual awareness task. Pupillary and gaze location measurements are recorded using either a ViewPoint\~VoltagePro.EyeLink 1000 Plus system, or Argus Science ETVision system. If using the ViewPoint\~VoltagePro system or the Argus Science ETVision system, participants will be asked to wear an eye tracker during the perceptual awareness task (similar to wearing sunglasses). If using the EyeLink 1000 Plus system, participants may be asked to place their head inside of a padded head-chin rest to stabilize head position

For the visual perceptual awareness task, the participant will be presented with barely perceptible visual stimuli. After a variable delay, the participant will be asked to report perception of each stimulus and identify its location.

Visual, auditory or tactile behavioral task will be performed during fMRI at the Yale MR Center. The subject will be asked to lie still in a 3T magnet scanner for up to 15-minute blocks. Each subject will have a sagittal T1-weighted localizer scan (3 minutes) and axial-oblique T1-weighted images (3 min). Multiple 5-15-minute imaging runs will be repeated up to 10 times. The subjects' responses will be recorded by a computer that is linked to the button box. The stimuli will be presented in blocks of 5 to 15 minutes throughout the MR imaging sequences.