Sheliga B M, Craighero L, Riggio L, Rizzolatti G
Istituto di Fisiologia Umana, Università di Parma, Italy.
Exp Brain Res. 1997 Apr;114(2):339-51. doi: 10.1007/pl00005642.
The aim of the present study was to investigate how spatial attention influences directional manual and saccadic reaction times. Two experiments were carried out. In experiment 1 subjects were instructed to perform pointing responses toward targets that were located either in the same or the opposite hemifield with respect to the hemifield in which an imperative stimulus was presented. In experiment 2, they were instructed to make saccadic or pointing responses. The direction of the responses was indicated by the shape of the imperative stimulus. Reaction time (RT), movement time, and, in experiment 2, saccadic trajectory were measured. The imperative stimulus location was either cued (endogenous attention) or uncued. In the latter case the imperative stimulus presentation attracted attention (exogenous attention). The main results of the experiments were the following: First, exogenous attention markedly decreased the RTs when the required movement was directed toward the imperative stimulus location. This directional effect was much stronger for pointing than for ocular responses. Second, endogenously allocated attention did not influence differentially RTs of pointing responses directed toward or away the attended hemifield. In contrast, endogenous attention markedly favored the saccadic responses when made away from the cued hemifield. Third, regardless of cueing, the direction of movement affected both pointing and saccadic reaction times. Saccadic reaction times were faster when the required movement was directed upward, while manual reaction times were faster when the movement was directed downward. Fourth, lateralized spatial attention deviated the trajectory of the saccades contralateral to the attention location. This pattern of results supports the notion that spatial attention depends on the activation of the same sensorimotor circuits that program actions in space.
本研究的目的是探讨空间注意力如何影响手动定向和眼跳反应时间。进行了两项实验。在实验1中，受试者被指示对位于与呈现指令性刺激的半视野相同或相对半视野中的目标进行指向反应。在实验2中，他们被指示进行眼跳或指向反应。反应的方向由指令性刺激的形状指示。测量了反应时间（RT）、运动时间，在实验2中还测量了眼跳轨迹。指令性刺激的位置要么被提示（内源性注意力），要么未被提示。在后一种情况下，指令性刺激的呈现吸引了注意力（外源性注意力）。实验的主要结果如下：第一，当所需运动指向指令性刺激位置时，外源性注意力显著缩短了反应时间。这种定向效应在指向反应中比在眼部反应中更强。第二，内源性分配的注意力并没有差异地影响指向朝向或远离被关注半视野的反应时间。相比之下，当眼跳反应远离被提示的半视野时，内源性注意力显著有利于眼跳反应。第三，无论是否有提示，运动方向都会影响指向和眼跳反应时间。当所需运动向上时，眼跳反应时间更快，而当运动向下时，手动反应时间更快。第四，侧向化空间注意力使与注意力位置对侧的眼跳轨迹发生偏移。这种结果模式支持了这样一种观点，即空间注意力依赖于在空间中规划动作的相同感觉运动回路的激活。
