Electromyography of Human Saccadic Eye Movements

The purpose of this paper is to report the results of an electromyographic study of saccadic movements (rapid versions) performed during a previously reported study of coactivity of the human extraocular muscles. 1 The technique employed has been previously described. 2 During a saccadic eye movement in any direction, there is increased electrical activity of all muscles except the one reciprocally inhibited by the required movements. The evidence for this is as follows: In Figure 1, the arrows from above indicate the start of horizontal saccades, the first to the left, the second to the right. During each saccade, there is increased electrical activity in both vertical recti, suggesting cocontraction. The agonist during the first saccade (right medial rectus) manifests increased activity. After the saccade the activity of each of the muscles returns to the level required by the final position of the eye. The first muscle channel (right lateral