Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
Department of Orthopedic Surgery, Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China.
Neural Plast. 2021 Apr 23;2021:8831379. doi: 10.1155/2021/8831379. eCollection 2021.
Amputation in adults is a serious procedure or traumatic outcome, one that leads to a possible "remapping" of limb representations (somatotopy) in the motor and sensory cortex. The temporal and spatial extent underlying reorganization of somatotopy is unclear. The aim of this study was to better understand how local and global structural plasticity in sensory-motor cortical networks changes temporally and spatially after upper-limb amputation.
We studied 8 healthy nonamputee control subjects and 16 complete upper-limb amputees. Resting-state MRI (rs-fMRI) was used to measure local and large-scale relative differences (compared to controls) in both the amplitude of low-frequency fluctuations (ALFF) and degree of centrality (DC) at 2 months, 6 months, and 12 months after traumatic amputation.
In amputees, rs-fMRI scans revealed differences in spatial patterns of ALFF and DC among brain regions over time. Significant relative increases in ALFF and DC were detected not only in the sensory and motor cortex but also in related cortical regions believed to be involved in cognition and motor planning. We observed changes in the magnitude of ALFFs in the pre- and postcentral gyrus and primary sensory cortex, as well as in the anterior cingulate, parahippocampal gyrus, and hippocampus, 2 months after the amputation. The regional distribution of increases/decreases in ALFFs and DC documented at 2-month postamputation was very different from those at 6 and 12-month postamputation.
Local and wide-spread changes in ALFFs in the sensorimotor cortex and cognitive-related brain regions after upper-limb amputation may imply dysfunction not only in sensory and motor function but also in areas responsible for sensorimotor integration and motor planning. These results suggest that cortical reorganization after upper extremity deafferentation is temporally and spatially more complicated than previously appreciated, affecting DC in widespread regions.
成年人截肢是一种严重的手术或创伤性结果，可能导致肢体在运动和感觉皮层中的代表（躯体定位）发生“重新映射”。躯体定位重组的时间和空间范围尚不清楚。本研究旨在更好地了解上肢截肢后感觉运动皮层网络的局部和全局结构可塑性如何在时间和空间上发生变化。
我们研究了 8 名健康的非截肢对照组受试者和 16 名完全上肢截肢者。使用静息状态 MRI(rs-fMRI)测量 2 个月、6 个月和 12 个月创伤性截肢后低频波动幅度(ALFF)和中心度(DC)的局部和大范围相对差异(与对照组相比)。
在截肢者中，rs-fMRI 扫描显示随着时间的推移，大脑区域的 ALFF 和 DC 的空间模式存在差异。不仅在感觉和运动皮层中，而且在被认为参与认知和运动规划的相关皮层区域中，也检测到 ALFF 和 DC 的相对增加。我们观察到在截肢后 2 个月，中央前回和中央后回以及初级感觉皮层的 ALFF 幅度发生了变化，前扣带、海马旁回和海马体也发生了变化。在截肢后 2 个月记录到的 ALFF 和 DC 增加/减少的区域分布与截肢后 6 个月和 12 个月的分布非常不同。
上肢截肢后感觉运动皮层和与认知相关的脑区的 ALFF 局部和广泛变化可能不仅意味着感觉和运动功能障碍，还意味着负责感觉运动整合和运动规划的区域功能障碍。这些结果表明，上肢去传入后的皮层重组在时间和空间上比以前认为的更为复杂，影响了广泛区域的 DC。
