Division of Brain, Imaging and Behaviour-Systems Neuroscience, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada M5T 2S8.
Proc Natl Acad Sci U S A. 2013 Nov 12;110(46):18692-7. doi: 10.1073/pnas.1312902110. Epub 2013 Oct 28.
Human minds often wander away from their immediate sensory environment. It remains unknown whether such mind wandering is unsystematic or whether it lawfully relates to an individual's tendency to attend to salient stimuli such as pain and their associated brain structure/function. Studies of pain-cognition interactions typically examine explicit manipulation of attention rather than spontaneous mind wandering. Here we sought to better represent natural fluctuations in pain in daily life, so we assessed behavioral and neural aspects of spontaneous disengagement of attention from pain. We found that an individual's tendency to attend to pain related to the disruptive effect of pain on his or her cognitive task performance. Next, we linked behavioral findings to neural networks with strikingly convergent evidence from functional magnetic resonance imaging during pain coupled with thought probes of mind wandering, dynamic resting state activity fluctuations, and diffusion MRI. We found that (i) pain-induced default mode network (DMN) deactivations were attenuated during mind wandering away from pain; (ii) functional connectivity fluctuations between the DMN and periaqueductal gray (PAG) dynamically tracked spontaneous attention away from pain; and (iii) across individuals, stronger PAG-DMN structural connectivity and more dynamic resting state PAG-DMN functional connectivity were associated with the tendency to mind wander away from pain. These data demonstrate that individual tendencies to mind wander away from pain, in the absence of explicit manipulation, are subserved by functional and structural connectivity within and between default mode and antinociceptive descending modulation networks.
人类的思维常常会游离于其直接的感觉环境之外。目前尚不清楚这种思维游离是无规律的,还是与个体注意突显刺激(如疼痛及其相关的大脑结构/功能)的倾向有规律地相关。对疼痛-认知相互作用的研究通常检查的是对注意力的明确操纵,而不是自发的思维游离。在这里,我们试图更好地代表日常生活中疼痛的自然波动,因此评估了自发地将注意力从疼痛上转移的行为和神经方面。我们发现,个体对疼痛的注意力倾向与疼痛对其认知任务表现的干扰效应有关。接下来,我们将行为发现与神经网络联系起来,从疼痛时的功能磁共振成像(fMRI)中获得了惊人的一致证据,同时还进行了思维探测、自发思维游离时的静息状态活动波动以及弥散磁共振成像(dMRI)。我们发现:(i)在思维游离于疼痛时,疼痛引起的默认模式网络(DMN)去激活现象减弱;(ii)DMN 和中脑导水管周围灰质(periaqueductal gray,PAG)之间的功能连接波动随疼痛时的自发注意力转移而动态变化;(iii)在个体之间,PAG-DMN 的结构连接越强,静息状态时 PAG-DMN 的功能连接越活跃,与远离疼痛的思维游离倾向越相关。这些数据表明,在没有明确操纵的情况下,个体远离疼痛的思维游离倾向,由默认模式和抗伤害性下行调制网络内和之间的功能和结构连接来支持。