Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, 08826, Republic of Korea.
Department of Biologic and Materials Sciences and Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI, 48109, USA.
Sci Rep. 2021 Dec 2;11(1):23323. doi: 10.1038/s41598-021-02616-1.
Dysfunctional thalamocortical interactions have been suggested as putative mechanisms of ineffective pain modulation and also suggested as possible pathophysiology of fibromyalgia (FM). However, it remains unclear which specific thalamocortical networks are altered and whether it is related to abnormal pain perception in people with FM. Here, we conducted combined vertex-wise subcortical shape, cortical thickness, structural covariance, and resting-state functional connectivity analyses to address these questions. FM group exhibited a regional shape deflation of the left posterior thalamus encompassing the ventral posterior lateral and pulvinar nuclei. The structural covariance analysis showed that the extent of regional deflation of the left posterior thalamus was negatively covaried with the left inferior parietal cortical thickness in the FM group, whereas those two regions were positively covaried in the healthy controls. In functional connectivity analysis with the left posterior thalamus as a seed, FM group had less connectivity with the periaqueductal gray compared with healthy controls, but enhanced connectivity between the posterior thalamus and bilateral inferior parietal regions, associated with a lower electrical pain threshold at the hand dorsum (pain-free point). Overall, our findings showed the structural thalamic alteration interacts with the cortical regions in a functionally maladaptive direction, leading the FM brain more responsive to external stimuli and potentially contributing to pain amplification.
功能失调的丘脑-皮质相互作用被认为是疼痛调节无效的潜在机制，也被认为是纤维肌痛（FM）的可能病理生理学基础。然而，目前尚不清楚哪些特定的丘脑-皮质网络发生了改变，以及这是否与 FM 患者的异常疼痛感知有关。在这里，我们进行了联合顶点的皮质下形状、皮质厚度、结构协变和静息状态功能连接分析来解决这些问题。FM 组表现出左侧后丘脑的局部形状瘪陷，包括腹侧后外侧核和丘脑枕核。结构协变分析显示，FM 组左侧后丘脑区域瘪陷的程度与左侧顶下皮质厚度呈负相关，而在健康对照组中，这两个区域呈正相关。在以左侧后丘脑为种子的功能连接分析中，FM 组与健康对照组相比，与导水管周围灰质的连接减少，但后丘脑与双侧顶下区域的连接增强，与手部背侧（无痛点）的电刺激疼痛阈值降低有关。总的来说，我们的研究结果表明，结构上的丘脑改变与皮质区域以功能失调的方式相互作用，导致 FM 大脑对外界刺激更敏感，并可能导致疼痛放大。
