Quantification of attention on pathological pain by using visual cues and functional brain imaging to reveal neural substrates of the attention

疼痛的感知取决于体感刺激的物理量，并受大脑认知功能的调节。在本研究中，我们重点研究了对疼痛感知影响最大的认知功能之一——注意。我们揭示了病理性疼痛与视觉感知之间的密切关系，因此我们旨在开发一种利用视觉线索量化病理性疼痛注意的新方法，并利用近红外光谱揭示与病理性疼痛相关的注意机制的神经基础。我们开发并使用了被称为“虚幻线运动”的实验范式。研究对象为单侧下肢慢性疼痛患者。通过这一范式，我们可以揭示注意力向受影响的一方偏离，并通过偏离的量来量化注意力。此外，我们用电刺激治疗慢性疼痛患者。通过电刺激患处肢体或未患处肢体，注意偏误分别得到增强或消除。这种效果不取决于电刺激的物理量，而取决于电感觉异常的感知量。因此，我们可以得出结论，病理性疼痛和外部体感刺激在注意机制上表现出相同的性质。此外，这一机制与大脑前额叶的活动有关。

Perception of pain is depending on physical quantity of the somatosensory stimulation, and it is modulated by cognitive function of the brain. In the present study, we focused on the attention which is one of cognitive functions most affecting pain perception. We have revealed the intimate relationship between pathological pain and visual perception, and thereby we aimed to develop a novel method to quantify the attention on pathological pain by using visual cues and also to reveal the neural substrates of the attentional mechanism which is related with pathological pain by using the near-infrared spectroscopy. We developed and used the experiment paradigm called as “the illusory line motion”. Patients with chronic pain in one extremity were participated in this study. By this paradigm, we could revealed that the attention deviates toward the affected side and the attention is quantified by amount of the deviation. Further, we treated chronic pain patients with the electrical nee stimulation. By applying the electrical stimulation on the affected or unaffected limb, the attentional bias was enhanced or neutralized respectively. Such effect depended on not physical quantity of the electrical stimulation but perceptional quantity of theelectrical paresthesia. Therefore, we can conclude that pathological pain and external somatosensory stimuli show same property for the attention mechanism. Moreover, this mechanism was associated with the prefrontal brain activity.