a, Visual detection task. The patient had to assess the presence or absence of a tumbler (6 × 6 cm2) on a white table (Michelson contrast = 55%) through a two-key response pad. The tumbler was positioned 80 cm in front of the patient. b, Experimental protocol. The entire experiment involved two sessions, with a total of 183 randomized object/no-object trials for a total duration of about 140 min. Each recording session included three conditions: natural binocular; natural monocular; and stimulated monocular. Each condition was divided into three blocks consisting of ten trials each: five object trials and five no-object trials (tumbler removed from the table). Each trial lasted 20 s. The patient was instructed to close his eyes during the first 5 s (while the experimenter placed/removed the tumbler on/from the table). The patient was then asked to open his eyes and was given 15 s to determine visually whether the tumbler was present on the table. c, Experimental setup. Behavioral responses and brain activity were simultaneously recorded during the visual test. EEG data analysis focused on the activity recorded from the occipital channels O1, Oz and O2.