Department of Neurology and Center for Advanced Imaging, Otto-von-Guericke-University, 39120 Magdeburg, Germany.
J Neurosci. 2012 Jul 11;32(28):9671-6. doi: 10.1523/JNEUROSCI.0439-12.2012.
Attentional selection on the basis of nonspatial stimulus features induces a sensory gain enhancement by increasing the firing-rate of individual neurons tuned to the attended feature, while responses of neurons tuned to opposite feature-values are suppressed. Here we recorded event-related potentials (ERPs) and magnetic fields (ERMFs) in human observers to investigate the underlying neural correlates of feature-based attention at the population level. During the task subjects attended to a moving transparent surface presented in the left visual field, while task-irrelevant probe stimuli executing brief movements into varying directions were presented in the opposite visual field. ERP and ERMF amplitudes elicited by the unattended task-irrelevant probes were modulated as a function of the similarity between their movement direction and the task-relevant movement direction in the attended visual field. These activity modulations reflecting globally enhanced processing of the attended feature were observed to start not before 200 ms poststimulus and were localized to the motion-sensitive area hMT. The current results indicate that feature-based attention operates in a global manner but needs time to spread and provide strong support for the feature-similarity gain model.
基于非空间刺激特征的注意力选择通过增加对关注特征敏感的单个神经元的发放率来增强感觉增益，而对相反特征值敏感的神经元的反应则受到抑制。在这里，我们记录了人类观察者的事件相关电位 (ERP) 和磁场 (ERMF)，以研究群体水平上基于特征的注意力的潜在神经相关性。在任务中，受试者关注出现在左视野中的移动透明表面，而在相反的视野中呈现执行不同方向短暂运动的任务无关探测刺激。由未被注意的任务无关探测刺激引起的 ERP 和 ERMF 幅度作为其运动方向与被关注视野中相关运动方向之间的相似性的函数进行调制。这些反映被关注特征的全局增强处理的活动调制被观察到在刺激后 200 毫秒之前不会开始，并且定位于运动敏感区域 hMT。当前的结果表明，基于特征的注意力以全局方式运作，但需要时间来传播，并为特征相似性增益模型提供了强有力的支持。
