Department of Anesthesiology, Nagoya University Graduate School of Medicine, Nagoya 467-8601, Japan.
Neuropsychiatric Department, Aichi Medical University, Nagakute 480-1131, Japan.
Cereb Cortex. 2023 Jun 8;33(12):7678-7687. doi: 10.1093/cercor/bhad071.
Wind-up is a nociceptive-specific phenomenon in which pain sensations are facilitated, in a frequency-dependent manner, by the repeated application of noxious stimuli of constant intensity, with invariant tactile sensations. Thus, cortical activities during wind-up could be an alteration associated with pain potentiation. We aimed to investigate somatosensory-evoked cortical responses and induced brain oscillations during wind-up by recording magnetoencephalograms. Wind-up was produced by the application of 11 consecutive electrical stimuli to the sural nerve, repeated at a frequency of 1 Hz without varying the intensity. The augmentation of flexion reflexes and pain rating scores were measured simultaneously as an index of wind-up. In the time-frequency analyses, the γ-band late event-related synchronization and the β-band event-related desynchronization were observed in the primary somatosensory region and the bilateral operculo-insular region, respectively. Repetitive exposure to the stimuli enhanced these activities, along with an increase in the flexion reflex magnitude. The evoked cortical activity reflected novelty, with no alteration to these repetitive stimuli. Observed oscillations enhanced by repetitive stimulation at a constant intensity could reflect a pain mechanism associated with wind-up.
上发条是一种伤害感受特异性现象，其中疼痛感觉以频率依赖性方式被反复施加恒定强度的有害刺激所促进，而触觉感觉不变。因此，上发条期间的皮质活动可能与疼痛增强有关。我们旨在通过记录脑磁图来研究上发条期间的体感诱发皮质反应和诱导的脑振荡。通过向腓肠神经施加 11 个连续的电刺激来产生上发条，以 1 Hz 的频率重复而不改变强度。弯曲反射和疼痛评分的增加被同时测量作为上发条的指标。在时频分析中，γ 带晚期事件相关同步和β 带事件相关去同步分别在初级体感区和双侧脑岛皮质区观察到。重复暴露于刺激增强了这些活动，同时弯曲反射幅度增加。诱发的皮质活动反映了新颖性，对这些重复刺激没有改变。在恒定强度下的重复刺激增强的观察到的振荡可能反映了与上发条相关的疼痛机制。
