Department of Pathological Physiology, Faculty of Medicine, Charles University in Prague Hradec Králové, Czech Republic.
Front Hum Neurosci. 2013 Jul 30;7:411. doi: 10.3389/fnhum.2013.00411. eCollection 2013.
The manipulation of attention can produce mismatch negativity-like components that are not necessarily connected to the unintentional sensory registration of the violation of probability-based regularity. For clinical purposes, attentional bias should be quantified because it can vary substantially among subjects and can decrease the specificity of the examination. This experiment targets the role of attention in the generation of visual mismatch negativity (vMMN). The visual regularity was generated by a sequence of two radial motions while subjects focused on visual tasks in the central part of the display. Attentional load was systematically varied and had three levels, no-load, easy, and difficult. Rare, deviant, and frequent standard motions were presented with a 10/60 ratio in oddball sequences. Data from 12 subjects was recorded from 64 channels and processed. vMMN was identified within the interval of 142-198 ms. The mean amplitude was evaluated during the aforementioned interval in the parietal and fronto-central regions. A general linear model for repeated measures was applied to the mean amplitude with a three-factor design and showed a significant difference [F (1, 11) = 17.40, p = 0.002] between standard and deviant stimuli and between regions [F (1, 11) = 8.40, p = 0.01]; however, no significant effect of the task [F (2, 22) = 1.26, p = 0.30] was observed. The unintentional detection of irregularity during the processing of the visual motion was independent of the attentional load associated with handling the central visual task. The experiment did not demonstrate an effect of attentional load manipulation on mismatch negativity (MMN) induced by the motion-sequence, which supports the clinical utility of this examination. However, used stimulation paradigm should be further optimized to generate mismatch negativity that is stable enough to be usable not only for group comparisons but also for a single subject assessment.
注意力的操控可以产生类似于失匹配负波（mismatch negativity，MMN）的成分，这些成分不一定与对违反概率规则的无意识感觉登记有关。出于临床目的，应该对注意力偏差进行量化，因为它在不同的受试者中可能有很大的差异，并且会降低检查的特异性。本实验旨在研究注意力在视觉失匹配负波（vMMN）产生中的作用。视觉规则是通过两个放射状运动序列产生的，而受试者则将注意力集中在显示中央部分的视觉任务上。注意力负荷被系统地改变，有三个水平，无负荷、容易和困难。在偶然序列中，以 10/60 的比例呈现罕见、偏离和频繁的标准运动。从 12 名受试者记录了 64 个通道的数据并进行了处理。vMMN 在 142-198ms 的间隔内被识别。在前述间隔内，在顶叶和额-中央区域评估了平均振幅。应用三因素设计的重复测量广义线性模型对平均振幅进行分析，结果显示标准刺激和偏离刺激之间以及区域之间存在显著差异[F（1，11）=17.40，p=0.002]；[F（1，11）=8.40，p=0.01]；然而，任务[F（2，22）=1.26，p=0.30]没有显著影响。在处理视觉运动的过程中，对不规则性的无意识检测与处理中央视觉任务相关的注意力负荷无关。该实验没有证明注意力负荷操纵对运动序列引起的失匹配负波（MMN）的影响，这支持了该检查的临床实用性。然而，应该进一步优化所使用的刺激范式，以产生足够稳定的失匹配负波，不仅可用于组间比较，也可用于单个受试者评估。
