Schneider Christoph, Pereira Michael, Tonin Luca, Millán José Del R
Chair for Brain-Machine Interface (CNBI), École Polytechnique Fédérale de Lausanne (EPFL), 1202, Geneva, Switzerland.
Laboratory of Cognitive Neuroscience (LNCO), École Polytechnique Fédérale de Lausanne (EPFL), 1202, Geneva, Switzerland.
Brain Topogr. 2020 Jan;33(1):48-59. doi: 10.1007/s10548-019-00725-9. Epub 2019 Jul 17.
Visual attention can be spatially oriented, even in the absence of saccadic eye-movements, to facilitate the processing of incoming visual information. One behavioral proxy for this so-called covert visuospatial attention (CVSA) is the validity effect (VE): the reduction in reaction time (RT) to visual stimuli at attended locations and the increase in RT to stimuli at unattended locations. At the electrophysiological level, one correlate of CVSA is the lateralization in the occipital [Formula: see text]-band oscillations, resulting from [Formula: see text]-power increases ipsilateral and decreases contralateral to the attended hemifield. While this [Formula: see text]-band lateralization has been considerably studied using electroencephalography (EEG) or magnetoencephalography (MEG), little is known about whether it can be trained to improve CVSA behaviorally. In this cross-over sham-controlled study we used continuous real-time feedback of the occipital [Formula: see text]-lateralization to modulate behavioral and electrophysiological markers of covert attention. Fourteen subjects performed a cued CVSA task, involving fast responses to covertly attended stimuli. During real-time feedback runs, trials extended in time if subjects reached states of high [Formula: see text]-lateralization. Crucially, the ongoing [Formula: see text]-lateralization was fed back to the subject by changing the color of the attended stimulus. We hypothesized that this ability to self-monitor lapses in CVSA and thus being able to refocus attention accordingly would lead to improved CVSA performance during subsequent testing. We probed the effect of the intervention by evaluating the pre-post changes in the VE and the [Formula: see text]-lateralization. Behaviorally, results showed a significant interaction between feedback (experimental-sham) and time (pre-post) for the validity effect, with an increase in performance only for the experimental condition. We did not find corresponding pre-post changes in the [Formula: see text]-lateralization. Our findings suggest that EEG-based real-time feedback is a promising tool to enhance the level of covert visuospatial attention, especially with respect to behavioral changes. This opens up the exploration of applications of the proposed training method for the cognitive rehabilitation of attentional disorders.
即使在没有眼球跳动的情况下，视觉注意力也可以在空间上定向，以促进对传入视觉信息的处理。这种所谓的隐蔽视觉空间注意（CVSA）的一种行为指标是有效性效应（VE）：对被关注位置的视觉刺激的反应时间（RT）缩短，而对未被关注位置的刺激的RT增加。在电生理水平上，CVSA的一个相关指标是枕叶α波段振荡的侧化，这是由对被关注半视野同侧的α功率增加和对侧的α功率降低导致的。虽然使用脑电图（EEG）或脑磁图（MEG）对这种α波段侧化进行了大量研究，但对于它是否可以通过训练在行为上改善CVSA却知之甚少。在这项交叉假对照研究中，我们使用枕叶α侧化的连续实时反馈来调节隐蔽注意的行为和电生理指标。14名受试者执行了一个线索化CVSA任务，包括对隐蔽关注的刺激进行快速反应。在实时反馈运行期间，如果受试者达到高α侧化状态，试验时间会延长。至关重要的是，通过改变被关注刺激的颜色，将正在进行的α侧化反馈给受试者。我们假设这种自我监测CVSA失误并因此能够相应地重新集中注意力的能力将导致在后续测试中CVSA表现的改善。我们通过评估VE和α侧化的前后变化来探究干预的效果。在行为上，结果显示反馈（实验性-假对照）和时间（前后）对有效性效应有显著交互作用，仅在实验条件下表现有所提高。我们没有发现α侧化的相应前后变化。我们的研究结果表明，基于EEG的实时反馈是提高隐蔽视觉空间注意水平的一个有前途的工具，特别是在行为变化方面。这为探索所提出的训练方法在注意力障碍认知康复中的应用开辟了道路。
