| 其他摘要 | The long-term influence of pain history recently began to attract attention of researchers in the pain field. Some studies have showed that thermal pain history could influence the structure and functions of the brains. In order to investigate the influence of mechanical pain history to greater extent, the present study examined the influence of past mechanical pain history upon the processing of painful stimuli and the pain-related information in different aspects of processing. Pain threshold was tested on the injured upper extremity of the people hurt only on one side, and compare them with that on the uninjured side and those of the healthy to discover whether the root of such influence exists at the spinal level or on the brain level. Voxel-based morphometry (VBM) was employed to test the long-term influence of past mechanical pain events upon the intensity of grey matter in the brain. Three tasks were used to test the effect of pain history upon the cognitive processing of the wounded. Probe-dot task was applied to test whether selective attention to the pain-related information exist in the wounded; categorization task was used to test whether the wounded react faster in the processing of pain-related information; phrase recall task was used to test the influence of memory of pain upon the processing of pain-related information. With help of above-mentioned tasks, we found that mechanical pain history imposes significant influence on the body and mind of the wounded. Three important findings emerged from this study: (1) For the first time we showed that mechanical pain events imposed significant influence upon the mechanical pain threshold but not the thermal pain threshold in the people with mechanical pain history. Mechanical pain events increased the pain threshold according to the intensity of the pain, and a “U” pattern of pain threshold was induced by the slight, moderate and severe pain history. (2) For the first time we showed that mechanical pain history in one side of upper extremity did not significantly reduce the intensity of grey matter in the brain, although the intensity of grey matter in the left parahippocampus was significantly negatively correlated with the pain intensity in the mechanical pain events, and this correlation may be specific to the upper extremity. (3) For the first time we found that mechanical pain history dose not influence the selective attention to the pain-related information, while significant influence was observed in the speed of processing of the pain-related information yet this was restricted to the processing of the information which highly matched the scene of past mechanical pain events. The recall of pain-related information was also affected by the mechanical pain history. In brief, pain-related history left with relatively significant influence or “trace” upon the wounded. On one side, we feel so lucky that mechanical pain history did not induce apparent decrease of grey matter; on the other side, as the chronic pain patients showed selective attention to the pain-related information, yet the subjects with mechanical pain history only showed significant changes in processing the sentence which depicted the scene in an accurate way, it is safe to say that mechanical pain history imposes restricted influence upon the cognitive processing of human beings.The long-term influence of pain history recently began to attract attention of researchers in the pain field. Some studies have showed that thermal pain history could influence the structure and functions of the brains. In order to investigate the influence of mechanical pain history to greater extent, the present study examined the influence of past mechanical pain history upon the processing of painful stimuli and the pain-related information in different aspects of processing. Pain threshold was tested on the injured upper extremity of the people hurt only on one side, and compare them with that on the uninjured side and those of the healthy to discover whether the root of such influence exists at the spinal level or on the brain level. Voxel-based morphometry (VBM) was employed to test the long-term influence of past mechanical pain events upon the intensity of grey matter in the brain. Three tasks were used to test the effect of pain history upon the cognitive processing of the wounded. Probe-dot task was applied to test whether selective attention to the pain-related information exist in the wounded; categorization task was used to test whether the wounded react faster in the processing of pain-related information; phrase recall task was used to test the influence of memory of pain upon the processing of pain-related information. With help of above-mentioned tasks, we found that mechanical pain history imposes significant influence on the body and mind of the wounded. Three important findings emerged from this study: (1) For the first time we showed that mechanical pain events imposed significant influence upon the mechanical pain threshold but not the thermal pain threshold in the people with mechanical pain history. Mechanical pain events increased the pain threshold according to the intensity of the pain, and a “U” pattern of pain threshold was induced by the slight, moderate and severe pain history. (2) For the first time we showed that mechanical pain history in one side of upper extremity did not significantly reduce the intensity of grey matter in the brain, although the intensity of grey matter in the left parahippocampus was significantly negatively correlated with the pain intensity in the mechanical pain events, and this correlation may be specific to the upper extremity. (3) For the first time we found that mechanical pain history dose not influence the selective attention to the pain-related information, while significant influence was observed in the speed of processing of the pain-related information yet this was restricted to the processing of the information which highly matched the scene of past mechanical pain events. The recall of pain-related information was also affected by the mechanical pain history. In brief, pain-related history left with relatively significant influence or “trace” upon the wounded. On one side, we feel so lucky that mechanical pain history did not induce apparent decrease of grey matter; on the other side, as the chronic pain patients showed selective attention to the pain-related information, yet the subjects with mechanical pain history only showed significant changes in processing the sentence which depicted the scene in an accurate way, it is safe to say that mechanical pain history imposes restricted influence upon the cognitive processing of human beings. |
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