Cortical wave amplitude and eye movement direction are correlated in REM sleep but not in waking

Eye movement related potentials were recorded bilaterally from the lateral geniculate body and visual cortex in five cats during REM sleep and waking. During REM sleep polygraphic recordings showed that these potentials have significantly greater amplitudes (primary waves) in the visual cortex and lateral geniculate body ipsilateral to the direction of the corresponding rapid eye movements. This amplitude difference was seen as a mean increase of 38.2% over the contralateral side and was found in 94.0% of wave pairs. The correlation between horizontal eye movement direction and amplitude of the waves is specific to REM sleep as there were no measurable differences in the waking state. These results are discussed with respect to possible mechanisms and functions of this lateralized wave system and its state dependency.