Donders Centre for Cognitive Neuroimaging, Box 9104, 6500 HE Nijmegen, The Netherlands; Institute for Computing and Information Sciences, Radboud University Nijmegen, Box 9010, 6500 GL Nijmegen, The Netherlands.
Neuroimage. 2014 Jan 15;85 Pt 2:803-9. doi: 10.1016/j.neuroimage.2013.07.031. Epub 2013 Jul 17.
Studies on metacognition have shown that participants can report on their performance on a wide range of perceptual, memory and behavioral tasks. We know little, however, about the ability to report on one's attentional focus. The degree and direction of somatosensory attention can, however, be readily discerned through suppression of alpha band frequencies in EEG/MEG produced by the somatosensory cortex. Such top-down attentional modulations of cortical excitability have been shown to result in better discrimination performance and decreased response times. In this study we asked whether the degree of attentional focus is also accessible for subjective report, and whether such evaluations correspond to the amount of somatosensory alpha activity. In response to auditory cues participants maintained somatosensory attention to either their left or right hand for intervals varying randomly between 5 and 32 seconds, while their brain activity was recorded with MEG. Trials were terminated by a probe sound, to which they reported their level of attention on the cued hand right before probe-onset. Using a beamformer approach, we quantified the alpha activity in left and right somatosensory regions, one second before the probe. Alpha activity from contra- and ipsilateral somatosensory cortices for high versus low attention trials were compared. As predicted, the contralateral somatosensory alpha depression correlated with higher reported attentional focus. Finally, alpha activity two to three seconds before the probe-onset was correlated with attentional focus. We conclude that somatosensory attention is indeed accessible to metacognitive awareness.
元认知研究表明，参与者可以报告他们在各种感知、记忆和行为任务上的表现。然而，我们对报告注意力焦点的能力知之甚少。然而，通过抑制感觉皮层产生的 EEG/MEG 中的 alpha 频段频率，可以很容易地辨别出躯体感觉注意力的程度和方向。这种自上而下的皮质兴奋性注意调节已被证明可以提高辨别性能和减少反应时间。在这项研究中，我们想知道注意力焦点的程度是否也可以进行主观报告，以及这些评估是否与躯体感觉 alpha 活动的量相对应。在响应听觉提示时，参与者将躯体感觉注意力保持在左手或右手，间隔时间随机在 5 到 32 秒之间，同时用 MEG 记录他们的大脑活动。试验通过探测音终止，参与者在探测音之前报告他们对提示手的注意力水平。使用波束形成方法，我们在探测前一秒量化了左右躯体感觉区域的 alpha 活动。将高注意力和低注意力试验的对侧和同侧躯体感觉皮质的 alpha 活动进行了比较。正如预测的那样，对侧躯体感觉 alpha 抑制与更高的报告注意力焦点相关。最后，探测前两到三秒的 alpha 活动与注意力焦点相关。我们得出结论，躯体感觉注意力确实可以进行元认知意识。
