Eyeblinks evoke potentials in the occipital brain region

The subjects performed voluntary eyeblinks under illuminated and dark laboratory conditions. 32-channel EEG recordings were averaged in relation to the eyeblinks and a brain electric source analysis (BESA) was performed. Two dipoles located near the eyeballs and a third dipole in the occipital region of the brain were found to explain the scalp potentials. The frontally located potentials described electromechanical potentials associated with lid movements and simultaneous eye movements. The occipitally located dipole explained a visually evoked potential with a first peak at about 180 ms after the maximum of the frontal blink potential. The visually evoked potential was observed only under illumination and was probably caused by changes in luminance during the eyeblinks.