Hemispheric asymmetries within the brain have been identified across taxa and have been extensively studied since the early 19th century. Here, we discuss lateralization of a brain structure, the amygdala, and how this lateralization is reshaping how we understand the role of the amygdala in pain processing. The amygdala is an almond-shaped, bilateral brain structure located within the limbic system. Historically, the amygdala was known to have a role in the processing of emotions and attaching emotional valence to memories and other experiences. The amygdala has been extensively studied in fear conditioning and affect but recently has been shown to have an important role in processing noxious information and impacting pain. The amygdala is composed of multiple nuclei; of special interest is the central nucleus of the amygdala (CeA). The CeA receives direct nociceptive inputs from the parabrachial nucleus (PBN) through the spino-parabrachio-amygdaloid pathway as well as more highly processed cortical and thalamic input via the lateral and basolateral amygdala. Although the amygdala is a bilateral brain region, most data investigating the amygdala’s role in pain have been generated from the right CeA, which has an overwhelmingly pro-nociceptive function across pain models. The left CeA has often been characterized to have no effect on pain modulation, a dampened pro-nociceptive function, or most recently an anti-nociceptive function. This review explores the current literature on CeA lateralization and the hemispheres’ respective roles in the processing and modulation of different forms of pain.

自 19 世纪初以来，大脑中的半球不对称已在整个分类群中被发现，并得到了广泛的研究。在这里，我们讨论大脑结构杏仁核的侧化，以及这种侧化如何重塑我们对杏仁核在疼痛处理中的作用的理解。杏仁核是位于边缘系统内的杏仁状双侧大脑结构。从历史上看，杏仁核在处理情绪和将情绪效价附加到记忆和其他经历中是众所周知的。杏仁核在恐惧条件反射和情感方面得到了广泛研究，但最近已被证明在处理有害信息和影响疼痛方面具有重要作用。杏仁核由多个核组成；特别感兴趣的是杏仁核 (CeA) 的中央核。CeA 通过脊髓-旁臂-杏仁核通路接收来自臂旁核 (PBN) 的直接伤害性输入，以及通过外侧和基底外侧杏仁核接收更高度加工的皮质和丘脑输入。尽管杏仁核是双侧大脑区域，但研究杏仁核在疼痛中的作用的大多数数据都是从右侧的 CeA 生成的，它在疼痛模型中具有压倒性的伤害感受功能。左侧的 CeA 通常被描述为对疼痛调节没有影响，抑制了伤害感受功能，或者最近的抗伤害感受功能。本综述探讨了当前关于 CeA 偏侧化的文献，以及大脑半球在不同形式疼痛的处理和调节中的各自作用。