ERP STUDIES OF SPATIAL SELECTIVE ATTENTION TO UPPERAND LOWER VISUAL FIELD

The main purpose of this paper is to study responses of even-related potential(ERP) elicited by spatial selective attention to upper and lower visual field and to explore the characteristics and differences in brain's processing of information from upper visual field and lower visual field. The main results of the experiments from 10 subjects are as follows:(1) Spatial selective attention to upper and lower visual fields produced a relative enhancement of P1, N1, and P2, like the results of attention to left and right visual fields;(2) As revealed by dipole localization, the early attentive effects (P1) to upper and lower visual field appeared to project to occipital cortex in a way of crossing, i.e. effects to lower field are inclined to project to dorsal area of occipital cortex, and effects to upper field are inclined to project to ventral area of occipital cortex; (3) A further result indicates that the degree of early attentive effects (P1) to upper and lower visual field are asymmetric, i.e. the dipolar moments of the early attentive effects to lower field are much weaker than that to upper visual field.