Effects of Sound Stimulation on the Visually Guided Saccades

We used saccade latency in a visually guided saccade task as an index to examine the effects of sound stimulation. A light-emitting diode (LED) was embedded in a dome-shaped screen. DC electro-oculography (EOG) was used to record eye movements. Sound stimuli were delivered from a speaker at the center of the dome or from headphones or speakers on either side. The task was to maintain visual fixation at the dome center while the LED was on (overlap paradigm). LEDs on either side of the target at 20° were illuminated 20-50 times per session, and control data were obtained without sound stimulation. When sound stimuli were delivered from the speaker at the center of the dome every 10 ms between Target ON -200 to +200 ms, the latency was shortened between Target ON -200 to + 60 ms. When the sound stimulation from the speaker and the target were on the same side (the ortho condition), the latency was even shorter, in the target were on the opposite side (the anti condition), there was less shortening of the latency. These data suggested that sound simulation causes the loss of attention when a subject is asked to pay attention to a central fixation point, and results in brief eye movement towards the target spot.