Department of Neurology, Seoul National University, Seoul, Republic of Korea.
PLoS One. 2012;7(6):e39886. doi: 10.1371/journal.pone.0039886. Epub 2012 Jun 27.
The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area's role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area's functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory.
额眼区（FEF）最初被认为是眼运动皮层，也与知觉功能有关，例如构建视觉显著图和转移视觉注意力。由于刺激和反应之间以及注意力转移和扫视准备等中间认知过程之间存在空间混淆，因此进一步剖析该区域在从视觉输入到眼动指令的转换中的作用一直很困难。在这里，我们开发了两项任务，其中视觉刺激和扫视反应在空间上是分离的（扩展记忆引导扫视任务），并且自上而下的注意力转移和扫视目标选择是独立的（四种替代的延迟扫视任务）。在恒河猴中可逆性失活额眼区，如预期的那样，破坏了对侧记忆引导的扫视，但在相同区域显示视觉检测完好无损。此外，当注意力的自上而下转移不是扫视目标选择的先决条件时，扫视行为受到损害，这表明失活效应与之前报道的自上而下注意力控制的功能障碍无关。这些发现强调了该区域功能的运动方面，特别是在扫视是由内部认知过程产生的情况下，包括视觉短期记忆和长期联想记忆。
