Effect of vibration stimulation to neck extensor muscles on reaction time in various saccadic eye movements.

We investigated the effect of vibration stimulation to the neck extensors on reaction time in various saccades that are controlled by different higher neural system. Visually guided, memory-guided and anti saccades were performed under no-vibration and vibration (frequency, 100 Hz; amplitude, 0.5 mm) applied to the trapezius muscles. For memory-guided and anti saccades, the reaction time under the vibration was significantly shorter than that under no-vibration. A significant correlation was found between the shortening of reaction time for memory-guided saccade and that for visually guided saccade (r = 0.726, p <.01), but no significant correlation was found between anti-saccade and other saccades. These findings suggested that the higher saccadic neural pathway was strongly activated during the vibration stimulation to the neck extensors, and furthermore the effect of activation on facilitatory and inhibitory functions differed among the three types of saccades.