Kastner S, Pinsk M A, De Weerd P, Desimone R, Ungerleider L G
Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA.
Neuron. 1999 Apr;22(4):751-61. doi: 10.1016/s0896-6273(00)80734-5.
When subjects direct attention to a particular location in a visual scene, responses in the visual cortex to stimuli presented at that location are enhanced, and the suppressive influences of nearby distractors are reduced. What is the top-down signal that modulates the response to an attended versus an unattended stimulus? Here, we demonstrate increased activity related to attention in the absence of visual stimulation in extrastriate cortex when subjects covertly directed attention to a peripheral location expecting the onset of visual stimuli. Frontal and parietal areas showed a stronger signal increase during this expectation than did visual areas. The increased activity in visual cortex in the absence of visual stimulation may reflect a top-down bias of neural signals in favor of the attended location, which derives from a fronto-parietal network.
当受试者将注意力指向视觉场景中的特定位置时，视觉皮层对该位置呈现的刺激的反应会增强，而附近干扰物的抑制作用会减弱。调节对被关注刺激与未被关注刺激反应的自上而下的信号是什么？在这里，我们证明，当受试者 covertly 将注意力指向预期视觉刺激出现的外周位置时，在没有视觉刺激的情况下，纹外皮层中与注意力相关的活动会增加。在此预期过程中，额叶和顶叶区域的信号增强比视觉区域更强。在没有视觉刺激的情况下，视觉皮层活动的增加可能反映了神经信号有利于被关注位置的自上而下的偏向，这源自额顶叶网络。
