Giehl Janet, Meyer-Brandis Gesa, Kunz Miriam, Lautenbacher Stefan
Department of Physiological Psychology, University of Bamberg , Germany.
Somatosens Mot Res. 2014 Mar;31(1):40-8. doi: 10.3109/08990220.2013.837045. Epub 2013 Dec 10.
To confirm the existence of an ongoing electroencephalogram (EEG) pattern that is truly suggestive of pain, tonic heat pain was induced by small heat pulses at 1 °C above the pain threshold and compared to slightly less intense tonic non-painful heat pulses at 1 °C below the pain threshold. Twenty healthy subjects rated the sensation intensity during thermal stimulation. Possible confounding effects of attention were thoroughly controlled for by testing in four conditions: (1) focus of attention directed ipsilateral or (2) contralateral to the side of the stimulation, (3) control without a side preference, and (4) no control of attention at all. EEG was recorded via eight leads according to the 10/20 convention. Absolute power was computed for the frequency bands delta (0.5-4 Hz), theta (4-8 Hz), alpha1 (8-11 Hz), alpha2 (11-14 Hz), beta1 (14-25 Hz), and beta2 (25-35 Hz). Ratings were clearly distinct between the heat and pain conditions and suggestive for heat and pain sensations. Manipulation of attention proved to be successful by producing effects on the ratings and on the EEG activity (with lower ratings and lower EEG activity (theta, beta1, 2) over central areas for side-focused attention). During pain stimulation, lower central alpha1 and alpha2 activity and higher right-parietal and right-occipital delta power were observed compared to heat stimulation. This EEG pattern was not influenced by the manipulation of attention. Since the two types of stimuli (pain, heat) were subjectively felt differently although stimulation intensities were nearby, we conclude that this EEG pattern is clearly suggestive of pain.
为了确认存在一种真正提示疼痛的持续脑电图（EEG）模式，通过在高于疼痛阈值1℃的小热脉冲诱发强直性热痛，并将其与低于疼痛阈值1℃的强度稍低的强直性非痛性热脉冲进行比较。20名健康受试者对热刺激期间的感觉强度进行评分。通过在四种条件下进行测试，充分控制了注意力可能产生的混杂效应：（1）注意力焦点指向刺激侧的同侧或（2）对侧，（3）无侧偏好的对照，以及（4）完全不控制注意力。根据10/20标准通过八个导联记录脑电图。计算了δ（0.5 - 4Hz）、θ（4 - 8Hz）、α1（8 - 11Hz）、α2（11 - 14Hz）、β1（14 - 25Hz）和β2（25 - 35Hz）频段的绝对功率。热刺激和疼痛刺激条件下的评分明显不同，提示了热觉和痛觉。事实证明，通过对评分和脑电图活动产生影响（对于侧焦点注意力，中央区域的评分和脑电图活动（θ、β1、β2）较低），注意力操纵是成功的。与热刺激相比，在疼痛刺激期间，观察到中央α1和α2活动较低，右侧顶叶和枕叶的δ功率较高。这种脑电图模式不受注意力操纵的影响。由于尽管刺激强度相近，但两种类型的刺激（疼痛、热）在主观感受上不同，我们得出结论，这种脑电图模式明显提示疼痛。
