Effects of Spatial Attention on the Visual-Evoked Neuromagnetic Response.

摘要

A number of studies have shown that selective attention to spatial location modulates the amplitudes of several visual evoked potential components recorded from posterior regions of the head (e.g., Eason, Harter and White, 1969; Harter, Aine, and Schroeder, 1982; Hillyard and Munte, 1984; Mangun and Hillyard, 1988). The early components, P1 and N1 (peak latencies: 90--135 and 140--170 msec, respectively), are thought to arise in one or more areas of visual cortex. Although it is generally assumed that such ERP effects reflect differential activation of populations of neurons at successive levels of the nervous system, little information is available about the neural structures responsible for such effects. We have employed neuromagnetic techniques in an attempt to identify more precisely the neural structures involved in selective attention to spatial location within the P1-N1 time sequence. In this study, effects of attention were assessed by comparing neural responses evoked by stimuli at a specified spatial location when subjects were required to attend and respond behaviorally to that location with neural responses to the same stimuli when subjects were required to attend and respond behaviorally to another location in the visual field. 7 refs., 3 figs.