Davis K D, Taylor S J, Crawley A P, Wood M L, Mikulis D J
Department of Surgery, University of Toronto and The Toronto Hospital, Ontario, Canada.
J Neurophysiol. 1997 Jun;77(6):3370-80. doi: 10.1152/jn.1997.77.6.3370.
The aims of the study were to use functional magnetic resonance imaging (fMRI) to 1) locate pain-related regions in the anterior cingulate cortex (ACC) of normal human subjects and 2) determine whether each subject's pain-related activation is congruent with ACC regions involved in attention-demanding cognitive processes. Ten normal subjects underwent fMRI with a 1.5-T standard commercial MRI scanner. A conventional gradient echo technique was used to obtain data from a single 4-mm sagittal slice of the left ACC, approximately 3.5 mm from midline. For each subject, interleaved sets of 6 images were obtained during a pain task, an attention-demanding task, and at rest, for a total of 36 images per task. Pain of different intensities was evoked via electrical stimulation of the right median nerve. The attention-demanding task consisted of silent word generation (verbal fluency). Additional experiments obtained data from the right ACC. A pixel-by-pixel statistical analysis of task versus rest images was used to determine task-related activated regions. The pain task resulted in a 1.6-4.0% increase in mean signal intensity within a small region of the ACC. The exact location of this activation varied from subject to subject, but was typically in the posterior part of area 24. The signal intensity changes within this region correlated with pain intensity reported by the subject. The attention-demanding tasks increased the mean signal intensity by 1.3-3.3% in a region anterior and/or superior to the pain-related activation in each subject. The activated region was typically larger than the pain-related activation. In some cases this activation was at or superior to the ACC border, near the supplementary motor area. These regions did not show any pain-intensity-related activation. In one subject both right and left ACC were imaged, revealing bilateral ACC activation during the attention task but only contralateral pain-related activation. These findings shed light on pain- and attention-related cognitive processes. The results provide evidence for a region in the posterior part of the ACC that is involved in pain and a more anterior region involved in other attention-demanding cognitive tasks.
本研究的目的是使用功能磁共振成像（fMRI）来：1）在正常人类受试者的前扣带回皮质（ACC）中定位与疼痛相关的区域，以及2）确定每个受试者与疼痛相关的激活是否与参与需要注意力的认知过程的ACC区域一致。十名正常受试者使用1.5-T标准商用MRI扫描仪进行了fMRI检查。采用传统梯度回波技术从距中线约3.5 mm的左侧ACC的单个4-mm矢状切片获取数据。对于每个受试者，在疼痛任务、需要注意力的任务和休息期间获取交错的6组图像，每个任务总共36张图像。通过电刺激右侧正中神经诱发不同强度的疼痛。需要注意力的任务包括无声单词生成（语言流畅性）。额外的实验从右侧ACC获取了数据。使用任务与休息图像的逐像素统计分析来确定与任务相关的激活区域。疼痛任务导致ACC的一个小区域内平均信号强度增加了1.6 - 4.0%。这种激活的确切位置因受试者而异，但通常在24区的后部。该区域内的信号强度变化与受试者报告的疼痛强度相关。需要注意力的任务使每个受试者中与疼痛相关激活区域前方和/或上方的一个区域的平均信号强度增加了1.3 - 3.3%。激活区域通常比与疼痛相关的激活区域大。在某些情况下，这种激活位于ACC边界处或上方，靠近辅助运动区。这些区域未显示出任何与疼痛强度相关的激活。在一名受试者中，对左右两侧的ACC都进行了成像，显示在注意力任务期间双侧ACC激活，但只有对侧与疼痛相关的激活。这些发现揭示了与疼痛和注意力相关的认知过程。结果为ACC后部参与疼痛的区域和更靠前参与其他需要注意力的认知任务的区域提供了证据。
