Program in Cognitive Neuroscience, Departments of Psychology and Biology, City College of the City University of New York, New York, New York 10031, USA.
J Neurosci. 2010 Mar 17;30(11):4024-32. doi: 10.1523/JNEUROSCI.5684-09.2010.
Retinotopically specific increases in alpha-band ( approximately 10 Hz) oscillatory power have been strongly implicated in the suppression of processing for irrelevant parts of the visual field during the deployment of visuospatial attention. Here, we asked whether this alpha suppression mechanism also plays a role in the nonspatial anticipatory biasing of feature-based attention. Visual word cues informed subjects what the task-relevant feature of an upcoming visual stimulus (S2) was, while high-density electroencephalographic recordings were acquired. We examined anticipatory oscillatory activity in the Cue-to-S2 interval ( approximately 2 s). Subjects were cued on a trial-by-trial basis to attend to either the color or direction of motion of an upcoming dot field array, and to respond when they detected that a subset of the dots differed from the majority along the target feature dimension. We used the features of color and motion, expressly because they have well known, spatially separated cortical processing areas, to distinguish shifts in alpha power over areas processing each feature. Alpha power from dorsal regions increased when motion was the irrelevant feature (i.e., color was cued), and alpha power from ventral regions increased when color was irrelevant. Thus, alpha-suppression mechanisms appear to operate during feature-based selection in much the same manner as has been shown for space-based attention.
视知觉空间注意分配过程中，与视觉野中不相关部分加工抑制相关的是纹状皮层alpha 频段（约 10Hz）的振荡功率增强。在这里，我们想知道这种 alpha 抑制机制是否也在基于特征的注意的非空间预期偏向中发挥作用。视觉词提示告知被试即将出现的视觉刺激（S2）的任务相关特征，同时记录高密度脑电图。我们检查了 cue-to-S2 间隔（约 2s）中的预期振荡活动。在逐个试次的基础上，被试被提示注意即将出现的点场数组的颜色或运动方向，并在他们检测到一小部分点与目标特征维度的多数点不同时做出反应。我们使用颜色和运动的特征，正是因为它们具有已知的、空间分离的皮层处理区域，以区分处理每个特征的区域的 alpha 功率变化。当运动是不相关的特征时（即，颜色被提示），背侧区域的 alpha 功率增加，而当颜色是不相关的特征时，腹侧区域的 alpha 功率增加。因此，alpha 抑制机制似乎在基于特征的选择中以与基于空间的注意相同的方式起作用。
