Distributed Attention Is Implemented through Theta-Rhythmic Gamma Modulation
Distributed Attention Is Implemented through Theta-Rhythmic Gamma Modulation
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DOI：
10.1016/j.cub.2015.07.048
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发表时间：
2015-08-31
期刊：
影响因子：
9.2
通讯作者：
Fries, Pascal
中科院分区：
文献类型：
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作者：
Landau, Ayelet Nina;Schreyer, Helene Marianne;Fries, Pascal
当受试者监视单个位置时，视觉目标检测取决于类似于 8 Hz 脑节律的预目标阶段 [1, 2]。当监控多个位置时，性能下降表明 8 Hz 节奏除以位置数量 [3]，表明不同位置被顺序采样。事实上，当受试者监测两个位置时，性能优势会以 4 Hz 的节奏交替变化[4]。这些表演交替是在将注意力重新集中到一个位置后显现出来的。尽管重置对于注意力来说是常见且重要的事件[5]，但尚不清楚在没有重置的情况下，持续的注意力是否会交替采样刺激。在这里，我们研究了是否可以通过持续的目标前大脑节律来揭示空间特定的注意力采样。视觉诱发的伽马带活动在空间注意力中发挥作用。因此，我们假设可以通过伽玛带活动的 4 Hz 调制来预测两个同时监测的刺激的表现。通过脑磁图（MEG）评估大脑节律，同时受试者监测单侧目标事件的双侧光栅刺激。相应的对侧伽玛带响应被相互减去，以隔离空间选择性的、与目标相关的波动。由此产生的侧化伽马能带活动 (LGA) 显示检测到的目标与错过的目标相反的目标前 4 Hz 相位。预目标 LGA 的 4 Hz 相位占性能调制的 14.5%。这些发现表明，空间注意力是一个持续进行的 theta 节奏采样过程，每个采样周期都是通过伽马带同步实现的。
When subjects monitor a single location, visual target detection depends on the pre-target phase of an similar to 8 Hz brain rhythm [1, 2]. When multiple locations are monitored, performance decrements suggest a division of the 8 Hz rhythm over the number of locations [3], indicating that different locations are sequentially sampled. Indeed, when subjects monitor two locations, performance benefits alternate at a 4 Hz rhythm[4]. These performance alternations were revealed after a reset of attention to one location. Although resets are common and important events for attention [5], it is unknown whether, in the absence of resets, ongoing attention samples stimuli in alternation. Here, we examined whether spatially specific attentional sampling can be revealed by ongoing pre-target brain rhythms. Visually induced gamma-band activity plays a role in spatial attention. Therefore, we hypothesized that performance on two simultaneously monitored stimuli can be predicted by a 4 Hz modulation of gamma-band activity. Brain rhythms were assessed with magnetoencephalography (MEG) while subjects monitored bilateral grating stimuli for a unilateral target event. The corresponding contralateral gamma-band responses were subtracted from each other to isolate spatially selective, target-related fluctuations. The resulting lateralized gamma-band activity (LGA) showed opposite pre-target 4 Hz phases for detected versus missed targets. The 4 Hz phase of pre-target LGA accounted for a 14.5% modulation in performance. These findings suggest that spatial attention is a theta-rhythmic sampling process that is continuously ongoing, with each sampling cycle being implemented through gamma-band synchrony.