Department of Neurology, University of Colorado Denver, Denver, CO, USA.
Neuroimage. 2012 Jan 16;59(2):1441-50. doi: 10.1016/j.neuroimage.2011.08.050. Epub 2011 Aug 30.
Neuroimaging studies have elucidated some of the underlying physiology of spontaneous and voluntary eye blinking; however, the neural networks involved in eye blink suppression remain poorly understood. Here we investigated blink suppression by analyzing fMRI data in a block design and event-related manner, and employed a novel hypothetical time-varying neural response model to detect brain activations associated with the buildup of urge. Blinks were found to activate visual cortices while our block design analysis revealed activations limited to the middle occipital gyri and deactivations in medial occipital, posterior cingulate and precuneus areas. Our model for urge, however, revealed a widespread network of activations including right greater than left insular cortex, right ventrolateral prefrontal cortex, middle cingulate cortex, and bilateral temporo-parietal cortices, primary and secondary face motor regions, and visual cortices. Subsequent inspection of BOLD time-series in an extensive ROI analysis showed that activity in the bilateral insular cortex, right ventrolateral prefrontal cortex, and bilateral STG and MTG showed strong correlations with our hypothetical model for urge suggesting these areas play a prominent role in the buildup of urge. The involvement of the insular cortex in particular, along with its function in interoceptive processing, helps support a key role for this structure in the buildup of urge during blink suppression. The right ventrolateral prefrontal cortex findings in conjunction with its known involvement in inhibitory control suggest a role for this structure in maintaining volitional suppression of an increasing sense of urge. The consistency of our urge model findings with prior studies investigating the suppression of blinking and other bodily urges, thoughts, and behaviors suggests that a similar investigative approach may have utility in fMRI studies of disorders associated with abnormal urge suppression such as Tourette syndrome and obsessive-compulsive disorder.
神经影像学研究已经阐明了自发性和自愿性眨眼的一些潜在生理学机制；然而，涉及眨眼抑制的神经网络仍知之甚少。在这里，我们通过分析 fMRI 数据的块设计和事件相关方式来研究眨眼抑制，并采用一种新的假设时变神经反应模型来检测与冲动积聚相关的大脑激活。眨眼会激活视觉皮层，而我们的块设计分析显示，激活仅限于中枕回，而中枕回、后扣带回和楔前叶区域的活动减少。然而，我们的冲动模型显示了一个广泛的激活网络，包括右侧大于左侧岛叶皮层、右侧腹外侧前额叶皮层、中扣带皮层和双侧颞顶叶皮层、初级和次级面部运动区以及视觉皮层。随后在广泛的 ROI 分析中对 BOLD 时间序列进行检查显示，双侧岛叶皮层、右侧腹外侧前额叶皮层以及双侧颞上回和颞中回的活动与我们的冲动假设模型强烈相关，表明这些区域在冲动积聚中起重要作用。特别是岛叶皮层的参与及其在内脏感觉处理中的作用，有助于支持该结构在眨眼抑制过程中冲动积聚中的关键作用。右侧腹外侧前额叶皮层的发现与其已知的在抑制控制中的作用相结合，表明该结构在维持对不断增加的冲动的自愿抑制中起作用。我们的冲动模型发现与先前研究眨眼抑制以及其他身体冲动、思想和行为的研究一致，这表明类似的研究方法可能在与异常冲动抑制相关的 fMRI 研究中具有实用价值，例如妥瑞氏症和强迫症。
