Top-Down Controlled Alpha Band Activity in Somatosensory Areas Determines Behavioral Performance in a Discrimination Task
Top-Down Controlled Alpha Band Activity in Somatosensory Areas Determines Behavioral Performance in a Discrimination Task
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DOI：
10.1523/jneurosci.5199-10.2011
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发表时间：
2011-04-06
影响因子：
5.3
通讯作者：
Jensen, Ole
中科院分区：
文献类型：
--
作者：
Haegens, Saskia;Haendel, Barbara F.;Jensen, Ole
大脑接收丰富的信息流，必须根据行为相关性进行处理。感觉系统的状态如何根据预期调整来上调或下调处理？我们使用脑磁图来研究刺激前 α 频带活动（8 - 14 Hz）是否反映了人类体感系统中注意力资源的分配。受试者执行触觉辨别任务，其中视觉提示将注意力引导到他们的右手或左手。注意力调节的强度是通过改变三个实验块中提示的可靠性（100%、75% 或 50% 有效提示）来控制的。虽然体感刺激前 α 功率在完全预测提示下强烈偏侧化 (100%)，但随着提示可靠性较低 (75%)，偏侧化会降低，如果提示根本没有预测价值 (50%)，则侧化实际上不存在。重要的是，α 侧化对受试者的行为表现产生积极影响：反应的准确性和速度都随着 α 侧化程度的提高而提高。这项研究表明，体感系统中刺激前 α 侧化的行为与视觉注意任务中观察到的后 α 活动类似。我们的研究结果扩展了这样的概念，即阿尔法带活动通过确定特定区域的参与和脱离来参与塑造工作大脑的功能结构：预期程度以分级方式调节感觉区域的阿尔法活动。因此，阿尔法活动处于自上而下的控制之下，并且似乎在设置感觉区域的状态以优化处理方面发挥着重要作用。
The brain receives a rich flow of information which must be processed according to behavioral relevance. How is the state of the sensory system adjusted to up- or downregulate processing according to anticipation? We used magnetoencephalography to investigate whether prestimulus alpha band activity (8 - 14 Hz) reflects allocation of attentional resources in the human somatosensory system. Subjects performed a tactile discrimination task where a visual cue directed attention to their right or left hand. The strength of attentional modulation was controlled by varying the reliability of the cue in three experimental blocks (100%, 75%, or 50% valid cueing). While somatosensory prestimulus alpha power lateralized strongly with a fully predictive cue (100%), lateralization was decreased with lower cue reliability (75%) and virtually absent if the cue had no predictive value at all (50%). Importantly, alpha lateralization influenced the subjects' behavioral performance positively: both accuracy and speed of response improved with the degree of alpha lateralization. This study demonstrates that prestimulus alpha lateralization in the somatosensory system behaves similarly to posterior alpha activity observed in visual attention tasks. Our findings extend the notion that alpha band activity is involved in shaping the functional architecture of the working brain by determining both the engagement and disengagement of specific regions: the degree of anticipation modulates the alpha activity in sensory regions in a graded manner. Thus, the alpha activity is under top-down control and seems to play an important role for setting the state of sensory regions to optimize processing.