Yeater Taylor D, Clark David J, Hoyos Lorraine, Valdes-Hernandez Pedro A, Peraza Julio A, Allen Kyle D, Cruz-Almeida Yenisel
Pain Research & Intervention Center of Excellence, University of Florida, University of Florida, Gainesville, FL, USA.
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, University of Florida, Gainesville, FL, USA.
Chronic Stress (Thousand Oaks). 2021 Jul 7;5:24705470211030273. doi: 10.1177/24705470211030273. eCollection 2021 Jan-Dec.
Autonomic dysregulation may lead to blunted sympathetic reactivity in chronic pain states. Autonomic responses are controlled by the central autonomic network (CAN). Little research has examined sympathetic reactivity and associations with brain CAN structures in the presence of chronic pain; thus, the present study aims to investigate how chronic pain influences sympathetic reactivity and associations with CAN brain region volumes.
Sympathetic reactivity was measured as change in skin conductance level (ΔSCL) between a resting reference period and walking periods for typical and complex walking tasks (obstacle and dual-task). Participants included 31 people with (n = 19) and without (n = 12) chronic musculoskeletal pain. Structural 3 T MRI was used to determine gray matter volume associations with ΔSCL in regions of the CAN (i.e., brainstem, amygdala, insula, and anterior cingulate cortex).
ΔSCL varied across walking tasks (main effect p = 0.036), with lower ΔSCL in chronic pain participants compared to controls across trials 2 and 3 under the obstacle walking condition. ΔSCL during typical walking was associated with multiple CAN gray matter volumes, including brainstem, bilateral insula, amygdala, and right caudal anterior cingulate cortex (p's < 0.05). The difference in ΔSCL from typical-to-obstacle walking were associated with volumes of the midbrain segment of the brainstem and anterior segment of the circular sulcus of the insula (p's < 0.05), with no other significant associations. The difference in ΔSCL from typical-to-dual task walking was associated with the bilateral caudal anterior cingulate cortex, and left rostral cingulate cortex (p's < 0.05).
Sympathetic reactivity is blunted during typical and complex walking tasks in persons with chronic pain. Additionally, blunted sympathetic reactivity is associated with CAN brain structure, with direction of association dependent on brain region. These results support the idea that chronic pain may negatively impact typical autonomic responses needed for walking performance via its potential impact on the brain.
自主神经调节异常可能导致慢性疼痛状态下交感神经反应迟钝。自主神经反应受中枢自主神经网络（CAN）控制。在慢性疼痛存在的情况下，很少有研究考察交感神经反应性以及与脑CAN结构的关联；因此，本研究旨在探究慢性疼痛如何影响交感神经反应性以及与CAN脑区体积的关联。
交感神经反应性通过静息参考期与典型及复杂步行任务（障碍物和双任务）步行期之间的皮肤电导水平变化（ΔSCL）来测量。参与者包括31名患有（n = 19）和未患有（n = 12）慢性肌肉骨骼疼痛的人。使用3T结构MRI来确定CAN区域（即脑干、杏仁核、岛叶和前扣带回皮质）中灰质体积与ΔSCL的关联。
ΔSCL在不同步行任务中有所不同（主效应p = 0.036），在障碍物步行条件下的试验2和3中，慢性疼痛参与者的ΔSCL低于对照组。典型步行期间的ΔSCL与多个CAN灰质体积相关，包括脑干、双侧岛叶、杏仁核和右侧尾侧前扣带回皮质（p值<0.05）。从典型步行到障碍物步行的ΔSCL差异与脑干中脑段和岛叶环状沟前段的体积相关（p值<0.05），无其他显著关联。从典型步行到双任务步行的ΔSCL差异与双侧尾侧前扣带回皮质和左侧喙侧扣带回皮质相关（p值<0.05）。
慢性疼痛患者在典型和复杂步行任务期间交感神经反应迟钝。此外，交感神经反应迟钝与CAN脑结构相关，关联方向取决于脑区。这些结果支持了慢性疼痛可能通过其对大脑的潜在影响对步行表现所需的典型自主神经反应产生负面影响的观点。
