Temporal and spatial dynamics of human forebrain activity during heat pain: Analysis by positron emission tomography
Temporal and spatial dynamics of human forebrain activity during heat pain: Analysis by positron emission tomography
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DOI：
10.1152/jn.2001.85.2.951
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发表时间：
2001-02-01
影响因子：
2.5
通讯作者：
Minoshima, S
中科院分区：
文献类型：
--
作者：
Casey, KL;Morrow, TJ;Minoshima, S
为了了解热痛过程中大脑激活模式的顺序，我们在每个受试者左前臂重复热刺激（40或50摄氏度; 5秒接触）的不同时间获得了正电子发射断层扫描（PET）大脑扫描。早期扫描开始于60 s刺激开始时;晚期扫描开始于40 s刺激后，持续整个60 s扫描期（总刺激持续时间100 s）。每名受试者（14名正常的右撇子受试者; 10名男性，4名女性;年龄18-42岁）在每次扫描后使用视觉模拟量表对感知的刺激强度进行评级（0 =无热，7 =疼痛阈值，10 =几乎无法忍受的疼痛）。40 ℃刺激的平均强度评级为2.19 +/- 1.22（平均值+/- SD），50 ℃刺激的平均评级为8.93 +/- 1.33。在扫描过程中，受试者没有报告早期和晚期扫描之间的差异。为了具体检查刺激持续时间的影响，其中8名受试者对20个连续的5秒接触热刺激（40或50摄氏度; 100秒的刺激）中的每一个的感知强度进行了评级。我们使用了一种图形方法来检测感知不愉快的变化。在40摄氏度的刺激过程中，感知强度或不愉快没有差异。然而，在50 degreesC的刺激，感知的不愉快增加，受试者认为最后五个，但不是第二个五，刺激更强烈的比前五个刺激。这些心理物理变化可以通过从早期到晚期PET扫描活动增加的大脑结构或仅在晚期扫描期间活动的大脑结构来介导。这些结构包括对侧M1/S1皮质、双侧S2和中间岛叶皮质、对侧VP丘脑、同侧内侧丘脑以及小脑的蚓部和副蚓部。在整个刺激过程中同样活跃的结构（对侧中前扣带回和前运动皮层）不太可能介导这些心理物理变化。一些皮质，但不是皮质下，结构显示出显着或边界激活，只有在早期扫描（同侧运动前皮质，对侧膝周前扣带，外侧前额叶，前岛皮质），他们可能介导疼痛相关的注意或预期功能。总体而言，结果表明：1）在重复有害热刺激期间，大脑激活模式和热痛感知都发生变化，2）在皮质下反应出现之前可以检测到皮质活动，3）相对于扫描周期的刺激时间可以，与心理物理测量一起，识别可能参与疼痛感知的大脑结构。
To learn about the sequence of brain activation patterns during heat pain, we acquired positron emission tomographic (PET) brain scans at different times during repetitive heat stimulation (40 or 50 degreesC; 5-s contact) of each subject's left forearm. Early scans began at the onset of 60 s of stimulation; late scans began after 40 s of stimulation, which continued throughout the 60-s scan period (total stimulus duration 100 s). Each subject (14 normal, right-handed subjects; 10 male, 4 female; ages 18-42) used a visual analog scale to rate the perceived stimulus intensity (0 = no heat, 7 = pain threshold, 10 = barely tolerable pain) after each scan. The 40 degreesC stimulation received an average intensity rating of 2.19 +/- 1.22 (mean +/- SD) and the 50 degreesC an average rating of 8.93 +/- 1.33. During the scan sessions, subjects did not report a difference between early and late scans. To examine the effect of the duration of stimulation specifically, 8 of these subjects rated the perceived intensity of each of 20 sequential 5-s duration contact heat stimuli (40 or 50 degreesC; 100 s of stimulation). We used a graphical method to detect changes in perceived unpleasantness. There was no difference in perceived intensity or unpleasantness during the 40 degreesC stimulation. However, during 50 degreesC stimulation, perceived unpleasantness increased and subjects perceived the last five, but not the second five, stimuli as more intense than the first five stimuli. These psychophysical changes could be mediated by brain structures with increasing activity from early to late PET scans or that are active only during late scans. These structures include the contralateral M1/S1 cortex, bilateral S2 and mid-insular cortex, contralateral VP thalamus, medial ipsilateral thalamus, and the vermis and paravermis of the cerebellum. Structures that are equally active throughout stimulation (contralateral mid-anterior cingulate and premotor cortex) are less likely to mediate these psychophysical changes. Some cortical, but not subcortical, structures showed significant or borderline activation only during the early scans (ipsilateral premotor cortex, contralateral perigenual anterior cingulate, lateral prefrontal, and anterior insular cortex); they may mediate pain-related attentive or anticipatory functions. Overall, the results reveal that 1) the pattern of brain activation and the perception of heat pain both change during repetitive noxious heat stimulation, 2) cortical activity can be detected before subcortical responses appear, and 3) timing the stimulation with respect to the scan period can, together with psychophysical measurements, identify brain structures that are likely to participate in the perception of pain.