Department of Biology, Queens College, City University of New York, Queens, NY 11367, USA; The Graduate Center, City University of New York, New York, NY 10016, USA.
Department of Biology, Queens College, City University of New York, Queens, NY 11367, USA.
Exp Neurol. 2022 Sep;355:114137. doi: 10.1016/j.expneurol.2022.114137. Epub 2022 Jun 4.
Organismal bilateral symmetry is associated with near-identical halves of the central nervous system, with certain functions displaying specialization through one brain hemisphere. The processing of pain in the brain as well as brain plasticity in the context of painful injuries have garnered much attention in recent decades. Noninvasive brain imaging studies in pain-free human subjects have identified multiple brain regions that are linked to the sensory and affective components of pain. Longlasting adaptations in brains of chronic pain sufferers have likewise been described, suggesting a mechanism for pain chronification. Invasive molecular and biochemical studies in animal models have expanded on these findings, with added emphasis on the role of specific genes and molecules involved. To date, the extent of hemispheric asymmetry in the context of pain is not well-understood. This topical review evaluates the evidence of hemispheric specialization observed in humans and rodent models of pain and compares it to findings where such asymmetry is absent. Our review shows conflicting information regarding the existence of pain-related asymmetry, and if so, the side to which it can be localized. This could be due to the heterogeneity of pain processing pathways, heterogeneity in study parameters, as well as differences in data reporting. With the advent of progressively sophisticated non-invasive tools that can be used in human subjects, in addition to more precise methods to visualize and control specific brain regions or neuronal ensembles in animal models, we predict that the next few decades will witness a better understanding of the supraspinal control and processing of chronic pain, including the role of each of its hemispheres.
生物体的双侧对称与中枢神经系统近乎相同的两半有关，某些功能通过一个大脑半球显示出专业化。近年来，大脑对疼痛的处理以及疼痛损伤背景下的大脑可塑性引起了广泛关注。在无痛人类受试者的非侵入性脑成像研究中，已经确定了与疼痛的感觉和情感成分相关的多个脑区。慢性疼痛患者大脑的持久适应也得到了描述，表明了疼痛慢性化的机制。在动物模型中的侵袭性分子和生化研究扩展了这些发现，并更加重视涉及的特定基因和分子的作用。迄今为止，疼痛背景下的半球不对称程度尚不清楚。本专题综述评估了在人类和疼痛的啮齿动物模型中观察到的半球专门化的证据，并将其与不存在这种不对称性的发现进行了比较。我们的综述显示了有关与疼痛相关的不对称性存在的相互矛盾的信息，如果存在，它可以定位到哪一侧。这可能是由于疼痛处理途径的异质性、研究参数的异质性以及数据报告的差异所致。随着可以在人类受试者中使用的越来越复杂的非侵入性工具的出现，以及更精确的可视化和控制动物模型中特定脑区或神经元集合的方法，我们预测未来几十年将更好地了解慢性疼痛的脊髓上控制和处理，包括其每个半球的作用。
