Cortical responses evoked by laser speckle.

Human cortical evoked responses elicited by patterns are very size and focus dependent, but those produced by moving laser speckle patterns (LASCERs) remain similar in amplitude and subjective sharpness over a wide (+/- 20 D) variation in added lens power. Moreover, cortical signal amplitudes evoked by speckle displays with high average spatial frequencies are significantly larger than those reported for check stimuli equivalent in spatial frequency.