Berlucchi G, Tassinari G, Marzi C A, Di Stefano M
Istituto di Fisiologia umana, Universita' di Verona, Italy.
Neuropsychologia. 1989;27(2):201-21. doi: 10.1016/0028-3932(89)90172-3.
It is known that reaction time (RT) for the detection of a light target at extrafoveal locations is lengthened by a previous non-informative light cue at the same location. We describe an additional inhibitory effect from cues remote from the target but occurring within the same lateral or altitudinal visual hemifield. Subjects made a speeded key-press response to the second of two successive light flashes in a pair while maintaining fixation. Each of the two flashes could appear at random in one of four positions, two in the right and two in the left visual fields, or two in the upper and two in the lower visual fields. We found an RT prolongation not only for cued over uncued positions, but also for within-field non-coincident cue-target pairs over between-fields cue-target pairs. The within-field inhibitory effect, though smaller than the same-location effect, was fully apparent even when the target occurred at 1 degree of visual angle from the midline and at 29 degrees from the cue. Both effects were seen with cue-target asynchronies ranging from 0.2 to 1.5 sec. The results are relevant to the understanding of the neural mechanisms for covert shifts of attention across the main meridians of the visual field.
众所周知，在中央凹外位置检测光目标的反应时间（RT）会因同一位置先前的非信息性光提示而延长。我们描述了一种来自远离目标但出现在同一侧方或高度视觉半视野内的提示的额外抑制作用。受试者在保持注视的同时，对一对连续光闪中的第二个光闪做出快速按键反应。两个光闪中的每一个都可以随机出现在四个位置之一，两个在右侧视野，两个在左侧视野，或者两个在上侧视野，两个在下侧视野。我们发现，不仅提示位置的反应时间比未提示位置延长，而且同侧非重合提示 - 目标对的反应时间比异侧提示 - 目标对延长。同侧抑制作用虽然比同位置作用小，但即使目标出现在离中线1度视角且离提示29度的位置时也完全明显。两种作用在提示 - 目标异步时间从0.2到1.5秒范围内都可见。这些结果与理解跨视野主要子午线的注意力隐蔽转移的神经机制有关。
