Ellerbrock Isabel, May Arne
Department of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Martinistrasse 52, 22046, Hamburg, Germany.
Brain Imaging Behav. 2015 Dec;9(4):848-53. doi: 10.1007/s11682-014-9345-5.
Functional magnetic resonance imaging (MRI) has been widely used in neuroscientific studies to investigate neural correlates of perception and higher cognitive functions. Early on, the MR-scanning procedure itself has been identified to create discomfort and anxiety in some individuals, which may influence task performance and perception. The present study analyzed behavioral differences in pain intensity ratings obtained in two distinct situations: MR environment and laboratory setting. Within our longitudinal study design twenty healthy volunteers were exposed daily to an identical paradigm consisting of 60 repeated noxious heat stimuli (46 °C) on 21 consecutive days. After each block of ten stimuli, participants were prompted to rate pain intensity on a visual analog scale (VAS). On days 1, 8, 14, and 21 ratings scores were obtained during a functional imaging scan, whereas on the remaining days the sessions were conducted in a laboratory. It has come to our attention that pain intensity ratings acquired in MR environment were significantly higher than behavioral data collected in the lab setting. Given that the stimuli were standardized and no task or distraction confounded the ratings, it is likely that the attentional focus on noxious stimulation was identical in both conditions. It seems that the highly artificial scanner environment as such is sufficient to increase awareness/alertness. Given that salience rather than pure nociceptive input has been suggested to explain functional imaging results in painful conditions, these findings highlight concerns regarding the comparability of behavioral data assembled across inconsistent settings.
功能磁共振成像（MRI）已广泛应用于神经科学研究，以探究感知和更高认知功能的神经关联。早期，人们就发现磁共振扫描程序本身会给一些人带来不适和焦虑，这可能会影响任务表现和感知。本研究分析了在两种不同情境下获得的疼痛强度评分的行为差异：磁共振环境和实验室环境。在我们的纵向研究设计中，20名健康志愿者连续21天每天都接受相同的范式，即60次重复的有害热刺激（46°C）。在每组10次刺激之后，要求参与者在视觉模拟量表（VAS）上对疼痛强度进行评分。在第1、8、14和21天，在功能成像扫描期间获得评分，而在其余日子里，实验在实验室中进行。我们注意到，在磁共振环境中获得的疼痛强度评分显著高于在实验室环境中收集的行为数据。鉴于刺激是标准化的，且没有任务或干扰因素混淆评分，两种情况下对有害刺激的注意力焦点可能是相同的。看起来高度人工化的扫描仪环境本身就足以提高意识/警觉性。鉴于有人提出显著性而非单纯的伤害性输入可以解释疼痛状态下的功能成像结果，这些发现凸显了对在不一致环境中收集的行为数据可比性的担忧。
