Distinct temporal filtering mechanisms are engaged during dynamic increases and decreases of noxious stimulus intensity.
Distinct temporal filtering mechanisms are engaged during dynamic increases and decreases of noxious stimulus intensity.
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DOI：
10.1097/j.pain.0000000000000250
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发表时间：
2015-10
期刊：
影响因子：
7.4
通讯作者：
Andersen OK
中科院分区：
文献类型：
--
作者：
Mørch CD;Frahm KS;Coghill RC;Arendt-Nielsen L;Andersen OK
偏置镇痛可以用反馈控制的近红外激光系统激活。观察到对温度降低的反应比对温度升高的反应更大且延迟。物理刺激在传入处理过程中受到明显的时间过滤，使得以某些速率发生的变化被放大，而其他的被减弱。伤害性信息的时间过滤仍然知之甚少。然而，偏置镇痛的现象，其中感知疼痛强度的不成比例的下降是由有害热刺激的轻微下降引起的，表明疼痛通路中的有效时间过滤。为了更好地理解物理刺激中的动态变化如何构建成疼痛体验，对皮肤温度和感知疼痛强度之间的传递函数进行建模。将温度控制的近红外（970 nm）激光刺激10秒，高于疼痛阈值，温度增加1°C、降低1 ° C或恒温，施加于健康人类志愿者的手背。皮肤温度由红外摄像机评估。激光热刺激诱发偏移镇痛。估计的传递函数显示，当温度升高1°C时（0.53秒[0.52-0.54秒]）比降低1°C时（1.15秒[1.12-1.18秒]）的延迟更短，增益更小（升高：0.89 [0.82-0.97];降低：2.61 [1.91-3.31]）。在0.06 Hz左右的频率下观察到最大增益。这些结果表明，在0.06 Hz附近发生的温度变化最容易感知，并且温度降低与可比温度升高相比，与更大但更慢的疼痛感知变化相关。这些心理物理学的研究结果证实了存在的差异机制参与的动态增加和减少有害刺激强度的时间过滤。
Offset analgesia could be activated with a feedback-controlled near-infrared laser system. Larger and delayed response to temperature decrease than to temperature increase was observed. Physical stimuli are subject to pronounced temporal filtering during afferent processing such that changes occurring at certain rates are amplified and others are diminished. Temporal filtering of nociceptive information remains poorly understood. However, the phenomenon of offset analgesia, where a disproportional drop in perceived pain intensity is caused by a slight drop in noxious heat stimulation, indicates potent temporal filtering in the pain pathways. To develop a better understanding of how dynamic changes in a physical stimulus are constructed into an experience of pain, a transfer function between the skin temperature and the perceived pain intensity was modeled. Ten seconds of temperature-controlled near-infrared (970 nm) laser stimulations above the pain threshold with a 1°C increment, decrement, or constant temperature were applied to the dorsum of the hand of healthy human volunteers. The skin temperature was assessed by an infrared camera. Offset analgesia was evoked by laser heat stimulation. The estimated transfer functions showed shorter latencies when the temperature was increased by 1°C (0.53 seconds [0.52-0.54 seconds]) than when decreased by 1°C (1.15 seconds [1.12-1.18 seconds]) and smaller gains (increase: 0.89 [0.82-0.97]; decrease: 2.61 [1.91-3.31]). The maximal gain was observed at rates around 0.06 Hz. These results show that temperature changes occurring around 0.06 Hz are best perceived and that a temperature decrease is associated with a larger but slower change in pain perception than a comparable temperature increase. These psychophysical findings confirm the existence of differential mechanisms involved in temporal filtering of dynamic increases and decreases in noxious stimulus intensity.