抄録
Binocular rivalry (BR) is the process where dissimilar images given to corresponding parts of the left and right eyes are perceived alternately at any moment in time. In an attempt to detect the neural activities related to the endogenous alternation of perceived images in BR, we have studied the potentials elicited by the alternation in six healthy subjects. Vertical (or horizontal) and horizontal (or vertical) gratings were presented to the left and right eyes separately. Subjects were instructed to press a button when perceived images were alternated, which triggered data acquisition. As the second experiment (binocular fusion, BF), identical vertical (or horizontal) gratings were presented to both eyes and were changed to horizontal (or vertical) gratings at the intervals of 0.9 to 1.5s. In BF, subjects pressed a button when perceived gratings were changed. As the third experiment (button press, BP), subjects pressed a button intentionally at random moment while identical gratings were presented continuously. EEGs were measured at 20 electrode positions on the scalp by averaging 100 trials in each experiment. A negative component peaking at -55ms was observed in the parietal and central areas in BF. In BR, a broad negative component between -400ms and 0ms was observed in the left parietal, left posterior temporal and left occipital areas. On the other hand, the negative component could not be observed in the BP where gratings were not alternated. These results suggest that the negative component may reflect a neural process related to the alternation of perceived images in both BR and BF. In particular, endogenous alternation in BR may be selectively related to the left parietal, left posterior temporal and left occipital areas.
