Brain dynamic mechanisms of scale effect in visual spatial attention.

The dynamic mechanisms of the early event-related potential scale effect of different attentive regions in the brain was studied. The paradigm of this experiment is the precue-target visual search paradigm by event-related potential technique. The results showed that the reaction time was shortened with the reduction of cue scale, a cue to how big the search area would be, and fixed target stimulus, while the amplitudes of P1 and N1 components of event-related potentials increased. These results not only provided the electrophysiological evidences that supported the zoom-lens theory, but also indicated that the zoom-lens effect happened at the early selected attention period. The results also showed that there existed two kinds of separation in the P2 effect.