Stancak Andrej, Cook Stephanie, Wright Hazel, Fallon Nicholas
Department of Psychological Sciences, University of Liverpool, Liverpool L69 7ZA, UK.
Department of Psychological Sciences, University of Liverpool, Liverpool L69 7ZA, UK.
Neuroimage. 2016 Jan 15;125:244-255. doi: 10.1016/j.neuroimage.2015.10.028. Epub 2015 Oct 23.
The origin of the conscious experience of pain in the brain is a continuing enigma in neuroscience. To shed light on the brain representation of a multifaceted pain experience in humans, we combined multivariate analysis of subjective aspects of pain sensations with detailed, single-trial analysis of electrophysiological brain responses. Participants were asked to fully focus on any painful or non-painful sensations occurring in their left hand during an interval surrounding the onset of noxious laser heat stimuli, and to rate their sensations using a set of visual analogue scales. Statistical parametric mapping was used to compute a multivariate regression analysis of subjective responses and single-trial laser evoked potentials (LEPs) at subject and group levels. Standardized Low Resolution Electromagnetic Tomography method was used to reconstruct sources of LEPs. Factor analysis of subjective responses yielded five factors. Factor 1, representing pain, mapped firstly as a negative potential at the vertex and a positive potential at the fronto-temporal region during the 208-260ms interval, and secondly as a strong negative potential in the right lateral frontal and prefrontal scalp regions during the 1292-1340ms interval. Three other factors, labelled "anticipated pain", "stimulus onset time", and "body sensations", represented non-specific aspects of the pain experience, and explained portions of LEPs in the latency range from 200ms to 700ms. The subjective space of pain during noxious laser stimulation is represented by one large factor featuring pain intensity, and by other factors accounting for non-specific parts of the sensory experience. Pain is encoded in two separate latency components with different scalp and brain representations.
大脑中疼痛的意识体验起源一直是神经科学领域的一个不解之谜。为了阐明人类多方面疼痛体验的大脑表征，我们将疼痛感觉主观方面的多变量分析与大脑电生理反应的详细单试次分析相结合。要求参与者在有害激光热刺激开始前后的一段时间内，充分关注左手出现的任何疼痛或非疼痛感觉，并使用一组视觉模拟量表对其感觉进行评分。使用统计参数映射在个体和群体水平上对主观反应和单试次激光诱发电位（LEP）进行多变量回归分析。采用标准化低分辨率电磁断层扫描方法重建LEP的来源。主观反应的因子分析产生了五个因子。因子1代表疼痛，首先在208 - 260毫秒间隔内表现为头顶的负电位和额颞区的正电位，其次在1292 - 1340毫秒间隔内表现为右侧额部和前额头皮区域的强负电位。其他三个因子，分别标记为“预期疼痛”、“刺激开始时间”和“身体感觉”，代表疼痛体验的非特异性方面，并解释了200毫秒至700毫秒潜伏期范围内LEP的部分情况。有害激光刺激期间疼痛的主观空间由一个反映疼痛强度的大因子以及其他解释感觉体验非特异性部分的因子来表征。疼痛在两个不同潜伏期成分中进行编码，具有不同的头皮和大脑表征。
