Abstract

The prelimbic cortex (PL) is actively engaged in pain modulation. The infralimbic cortex (IL) has been reported to regulate the PL. However, how this regulation affects pain remains unclear. In the present study, we recorded temporary hyper-activity of PL pyramidal neurons responding to nociceptive stimuli, but a temporary hypo-function of the IL by in vivo electrophysiological recording in rats with peripheral inflammation. Manipulation of the PL or IL had opposite effects on thermal hyperalgesia. Furthermore, the functional connectivity and chemogenetic regulation between the subregions indicated an inhibitory influence of the IL on the PL. Activation of the pathway from the IL to the PL alleviated thermal hyperalgesia, whereas its inhibition exacerbated chronic pain. Overall, our results suggest a new mechanism underlying the role of the medial prefrontal cortex in chronic pain: hypo-function of the IL leads to hyperactivity of the PL, which regulates thermal hyperalgesia, and thus contributes to the chronicity of pain.

中文翻译：

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慢性炎性疼痛大鼠边缘下皮层的动态变化及其对边缘前皮层的调节

摘要

前边缘皮质 (PL) 积极参与疼痛调节。据报道，边缘下皮层 (IL) 可以调节 PL。然而，这种调节如何影响疼痛仍不清楚。在本研究中，我们通过体内电生理学记录，在患有外周炎症的大鼠中记录了 PL 锥体神经元对伤害性刺激做出反应的暂时性过度活跃，但 IL 暂时性功能低下。操纵 PL 或 IL 对热痛觉过敏具有相反的作用。此外，亚区域之间的功能连接和化学遗传学调控表明 IL 对 PL 具有抑制作用。从 IL 到 PL 通路的激活减轻了热痛觉过敏，而其抑制则加剧了慢性疼痛。总的来说，我们的结果表明了内侧前额叶皮层在慢性疼痛中作用的新机制：IL 功能低下导致 PL 过度活跃，PL 调节热痛觉过敏，从而导致慢性疼痛。