EYE ACCELERATION DURING LARGE HORIZONTAL SACCADES IN MAN

The pattern of acceleration was recorded during horizontal saccadic ey e movements using a lightweight accelerometer fixed to a scleral conta ct lens. Horizontal saccades of 15-20 degrees were dominated by either several pulses of acceleration, with a frequency of around 40 Hz, or a single acceleration-deceleration wave followed by lower amplitude po lyphasic activity of about 80 Hz. These features are unlikely to be du e to slippage or resonance in the contact lens-accelerometer system, a s very similar patterns of acceleration were simultaneously recorded w ith an accelerometer taped over the closed eyelid of the contralateral eye. Analysis of simultaneous surface electromyogram recordings indic ated that the multicomponent acceleration profiles were the product, a t least in part? of the rhythmic and synchronous modulation of eye mus cle discharge during saccades.