SEVERAL investigators1-3 have recognized that intermittent visual stimulation such as occurs when the eyes scan a picture is associated in man with the appearance of discrete electric discharges, lambda waves, in the parietal and occipital areas of the scalp. A previous communication4 reported the findings of similar waves in the monkey, dog, cat, and rabbit. Others working with monkeys,5,6 dogs,7 and cats8 also noted the occurrence of discharges in the occipital region, which they likewise considered to be the equivalent of lambda waves in the human. The studies to be reported represent an extension of those previously reported findings.4 Not only were conventional scalp, extradural, and depth recordings made but computer summation techniques also were employed; in particular a Computer of Average Transients (CAT) was triggered by eye-movement potentials, and the succeeding brain activity was summed.9 Thus, it was possible to sum