P100 latency of the visual evoked potential by hemifield pattern reversal stimulation during isometric contraction of the unilateral shoulder girdle elevator

We investigated changes in the P100 latency of the visual evoked potential by the hemifield pattern reversal stimulation during isometric contraction of the unilateral shoulder girdle elevator. Muscle contraction force was set at 20% of maximal voluntary contraction. Significant shortening of the P100 latency was found in both hemifield visual sides during the left contraction. On the other hand, during the right contraction, no significant shortening was found in both hemifield visual sides. This suggests that the neural pathway until the visual cortex is not influenced by the right contraction but by the left contraction of the shoulder girdle elevator and that the influence is observed in both hemispheres.