Lambda response by orientation of striped patterns.

A lambda response is an averaged occipital EEG potential associated with the offsets of saccadic eye movements. In the present experiment, two participants were asked to make horizontal saccades across horizontal or vertical white-black stripes. Analysis of orientations of striped patterns showed horizontal saccades across vertical stripes produced larger amplitudes of the lambda response than did horizontal saccades across horizontal stripes. Therefore, when the lambda response is used as the index of mental workload, it is necessary to take notice of the orientation of stimulus pattern.