Investigation of mechanisms for human pain perception and its clinical application, mainly on function of signals ascending through C fibers.

目的：我们研究了电生理研究，利用脑电图（EEG），脑磁图（MEG）和重复经颅磁刺激（rTMS）以及功能磁共振成像（fMRI）对人类疼痛perception.METHODS：为记录活动后A δ纤维刺激有关的第一次疼痛，几种激光，如CO2，Tm：YAG和氩激光，现在被广泛使用。这种活动通常被称为激光诱发电位（LEP）。我们还开发了一种新的方法，表皮刺激（ES），这是有用的记录大脑活动的信号上升通过A δ纤维。对于记录活动后C纤维刺激有关的第二次疼痛，几种方法已被使用，但弱CO2激光刺激施加到皮肤的微小区域最近used.RESULTS：EEG和MEG的结果C纤维刺激后，除了较长的潜伏期是类似的A δ纤维刺激。我们还研究了rTMS对急性疼痛感知的影响。rTMS减轻了由皮内注射辣椒素引起的急性疼痛，辣椒素激活了C纤维，但它增强了由激光刺激引起的急性疼痛，激活了A δ纤维。在fMRI研究中，刺激A δ和C纤维后，双侧半球的丘脑、次级体感皮层（SII）、丘脑和扣带皮层都被激活。然而，只有一个小的区域，6/8/32区和前丘脑运动区（SMA）被选择性激活后，C纤维刺激。讨论：除了上述方法，一个有前途的方法在不久的将来是分析频带的变化。这种方法可能会被用于评估持续紧张性疼痛，如癌症疼痛，诱发反应研究无法评估。

OBJECTIVE : We studied electrophysiological studies using electroencephalography (EEG), magnetoencephalography (MEG) and repetitive transcranial magnetic stimulation (rTMS) as well as functional magnetic resonance imaging (fMRI) on human pain perception.METHODS : For recording activities following A delta fiber stimulation relating to first pain, several kinds of lasers such as CO2, Tm : YAG and argon lasers are now widely used. The activity is frequently termed laser evoked potential (LEP). We also developed new method, epidermal stimulation (ES), which is useful for recording brain activities by the signals ascending through A delta fibers. For recording activities following C fiber stimulation relating to second pain, several methods have been used but weak CO2 laser stimuli applied to tiny areas of the skin were recently used.RESULTS : EEG and MEG findings following C fiber stimulation were similar to those following A delta fiber stimulation except for a longer latency. We also studied the effect of rTMS on acute pain perception. rTMS alleviated acute pain induced by intracutaneous injection of capsaicin, which activated C fibers, but it enhanced acute pain induced by laser stimulation, which activated A delta fibers. As for fMRI studies, thalamus, secondary somatosensory cortex (SII), insula and cingulate cortex in the bilateral hemispheres were activated following both A delta and C fiber stimulation. However, only a small region, area 6/8/32 and pre supplementally motor area (SMA) were selectively activated following C fiber stimulation.DISCUSSION : In addition to the above methods, one promising approach in the near future is to analyze the change of a frequency band. This method will probably be used for evaluation of continuous tonic pain such as cancer pain, which evoked response studies cannot evaluate.