Bereitschaftspotential preceding spontaneous and voluntary eyelid blinks in normal individuals.

Objective: To investigate the Bereitschaftspotential (BP) preceding spontaneous and voluntary eyelid blinks in normal subjects.

Methods: Eighteen healthy individuals (10 female) between 17 and 60years (mean 35) were studied. The EEG was recorded from 11 scalp positions of the 10-20 international electrode placement system referenced to linked mastoids. The vertical electrooculogram (VEOG) was recorded from two electrodes positioned above and below the right eye. The ground electrode was placed in the right clavicle. The recordings were obtained during spontaneous and voluntary eyelid blinks. Two-second EEG segments before the onset of the blink potential (visually identified at the VEOG channel) were averaged and analyzed off-line. The statistical significance of differences was evaluated by repeated-measures analysis of variance with Geisser-Greenhouse correction for violation of sphericity and the Newman-Keuls test was used for post hoc comparisons.

Results: A BP starting around -1700ms prior to the onset of voluntary blink was observed; it had average amplitude in the negative peak of 3.3μV. There was no BP preceding spontaneous blinking.

Conclusion: A BP precedes voluntary blinks but not spontaneous blinks.

Significance: This is the first study evaluating the BP preceding spontaneous and voluntary eye blinks.