Khan Aarlenne Z, Song Joo-Hyun, McPeek Robert M
Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
J Vis. 2011 Jan 7;11(1):9. doi: 10.1167/11.1.9.
Prior to the onset of a saccade or a reach, attention is directed to the goal of the upcoming movement. However, it remains unknown whether attentional resources are shared across effectors for simultaneous eye and hand movements. Using a 4-AFC shape discrimination task, we investigated attentional allocation during the planning of a saccade alone, reach alone, or combined saccade and reach to one of five peripheral locations. Target discrimination was better when the probe appeared at the goal of the impending movement than when it appeared elsewhere. However, discrimination performance at the movement goal was not better for combined eye-hand movements compared to either effector alone, suggesting a shared limited attentional resource rather than separate pools of effector-specific attention. To test which effector dominates in guiding attention, we then separated eye and hand movement goals in two conditions: (1) cued reach/fixed saccade--subjects made saccades to the same peripheral location throughout the block, while the reach goal was cued and (2) cued saccade/fixed reach--subjects made reaches to the same location, while the saccade goal was cued. For both conditions, discrimination performance was consistently better at the eye goal than the hand goal. This indicates that shared attentional resources are guided predominantly by the eye during the planning of eye and hand movements.
在扫视或伸手动作开始之前，注意力会指向即将进行的动作的目标。然而，对于同时进行眼动和手动时注意力资源是否在不同效应器之间共享，目前尚不清楚。我们使用一个4-AFC形状辨别任务，研究了单独进行扫视计划、单独进行伸手计划或扫视与伸手结合指向五个周边位置之一时的注意力分配情况。当探测刺激出现在即将进行的动作的目标位置时，目标辨别比出现在其他位置时更好。然而，与单独使用任一效应器相比，眼手联合动作时在动作目标处的辨别表现并没有更好，这表明存在共享的有限注意力资源，而非效应器特异性注意力的独立储备。为了测试在引导注意力方面哪个效应器占主导，我们随后在两种情况下分离了眼动和手动的目标：（1）提示伸手/固定扫视——在整个实验块中，受试者向同一周边位置进行扫视，同时提示伸手目标；（2）提示扫视/固定伸手——受试者向同一位置伸手，同时提示扫视目标。在这两种情况下，在眼动目标处的辨别表现始终优于手动目标处。这表明在眼动和手动动作计划过程中，共享的注意力资源主要由眼动引导。
