Links between eye movement preparation and the attentional processing of tactile events: an event-related brain potential study.

OBJECTIVE: We investigated whether the covert preparation of saccadic eye movements results in spatially specific modulations of somatosensory processing.

METHODS: ERPs were recorded in a spatial cueing experiment where auditory cues preceded tactile stimuli delivered to the left or right hand. In the Saccade task, cues signalled that an eye movement towards the left or right hand had to be prepared. In the Covert Attention task, cues signalled the direction of a covert shift of tactile attention.

RESULTS: A lateralized component previously observed during cued shifts of spatial attention (ADAN) was elicited in the cue-target interval in both tasks. The somatosensory N140 component was enhanced for tactile stimuli presented to the hand on the cued side. This modulation was present not just in the Covert Attention task, but also in the Saccade task. Longer-latency effects of spatial cueing were only present in the Covert Attention task.

CONCLUSIONS: Covert shifts of attention and saccade preparation have similar effects on early stages of tactile processing, suggesting that both are mediated by overlapping control processes.

SIGNIFICANCE: These findings support the premotor theory of attention by demonstrating that the programming of eye movements has spatially selective effects on somatosensory processing.