Institute of Clinical Neuroscience and Medical Psychology, University of Dusseldorf, Dusseldorf, Germany.
PLoS One. 2010 Dec 28;5(12):e15804. doi: 10.1371/journal.pone.0015804.
In healthy subjects repeated tactile stimulation in a conditioning test stimulation paradigm yields attenuation of primary (S1) and secondary (S2) somatosensory cortical activation, whereas a preceding painful stimulus results in facilitation.
METHODOLOGY/PRINCIPAL FINDINGS: Since previous data suggest that cognitive processes might affect somatosensory processing in S1, the present study aims at investigating to what extent cortical reactivity is altered by the subjective estimation of pain. To this end, the effect of painful and tactile stimulation on processing of subsequently applied tactile stimuli was investigated in patients with fibromyalgia syndrome (FMS) and in subjects with masochistic behaviour (MB) by means of a 122-channel whole-head magnetoencephalography (MEG) system. Ten patients fulfilling the criteria for the diagnosis of FMS, 10 subjects with MB and 20 control subjects matched with respect to age, gender and handedness participated in the present study. Tactile or brief painful cutaneous laser stimuli were applied as conditioning stimulus (CS) followed by a tactile test stimulus (TS) 500 ms later. While in FMS patients significant attenuation following conditioning tactile stimulation was evident, no facilitation following painful stimulation was found. By contrast, in subjects with MB no attenuation but significant facilitation occurred. Attenuation as well as facilitation applied to cortical responses occurring at about 70 ms but not to early S1 or S2 responses. Additionally, in FMS patients the amount of attenuation was inversely correlated with catastrophizing tendency.
The present results imply altered cortical reactivity of the primary somatosensory cortex in FMS patients and MB possibly reflecting differences of individual pain experience.
在健康受试者中，重复的触觉刺激在条件刺激测试刺激范式中会导致初级（S1）和次级（S2）体感皮层激活的衰减，而先前的疼痛刺激则会导致促进。
方法/主要发现：由于先前的数据表明认知过程可能会影响 S1 中的体感处理，因此本研究旨在调查主观疼痛评估在多大程度上改变了皮质反应性。为此，通过使用 122 通道全头磁脑图（MEG）系统，研究了纤维肌痛综合征（FMS）患者和受虐行为（MB）患者中疼痛和触觉刺激对随后施加的触觉刺激处理的影响。本研究纳入了 10 名符合 FMS 诊断标准的患者、10 名 MB 患者和 20 名年龄、性别和惯用手匹配的对照组受试者。触觉或短暂的疼痛性皮肤激光刺激作为条件刺激（CS）施加，然后在 500 毫秒后施加触觉测试刺激（TS）。在 FMS 患者中，明显的触觉刺激后衰减是明显的，但没有发现疼痛刺激后的促进作用。相比之下，在 MB 患者中，没有衰减但存在显著的促进作用。衰减和促进适用于大约 70 毫秒时的皮质反应，而不适用于早期 S1 或 S2 反应。此外，在 FMS 患者中，衰减的程度与灾难化倾向呈负相关。
本研究结果表明 FMS 患者和 MB 患者的初级体感皮层皮质反应性改变，可能反映了个体疼痛体验的差异。
