Comparison of two types of visual evoked potentials: pattern reversal and eye movement (lambda).

The averaged visual evoked potentials of 10 normal subjects were studied either with eyes fixated while a chequerboard reversed or when they moved their eyes across the stationary chequerboard. The resulting occipital potentials averaged using a computer of averaged transients were discrepant for the 2 conditions. The latency of the P100 component was similar allowing for the difference in latency in the computer triggering system but the resulting wave forms were different. There was a prominent negative component preceding the P100 in the lambda response and a prominent negative component following the P100 for the pattern shift. The possible reasons for the findings are discussed.