Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA.
Neurorehabil Neural Repair. 2012 Jan;26(1):7-19. doi: 10.1177/1545968311411054. Epub 2011 Jul 29.
Recent studies have shown that focal injuries can have remote effects on network function that affect behavior, but these network-wide repercussions are poorly understood.
This study tested the hypothesis that lesions specifically to the outflow tract of a distributed network can result in upstream dysfunction in structurally intact portions of the network. In the somatomotor system, this upstream dysfunction hypothesis predicted that lesions of the corticospinal tract might be associated with functional disruption within the system. Motor impairment might then reflect the dual contribution of corticospinal damage and altered network functional connectivity.
A total of 23 subacute stroke patients and 13 healthy controls participated in the study. Corticospinal tract damage was quantified using a template of the tract generated from diffusion tensor imaging in healthy controls. Somatomotor network functional integrity was determined by resting state functional connectivity magnetic resonance imaging.
The extent of corticospinal damage was negatively correlated with interhemispheric resting functional connectivity, in particular with connectivity between the left and right central sulcus. Although corticospinal damage accounted for much of the variance in motor performance, the behavioral impact of resting connectivity was greater in subjects with mild or moderate corticospinal damage and less in those with severe corticospinal damage.
Our results demonstrated that dysfunction of cortical functional connectivity can occur after interruption of corticospinal outflow tracts and can contribute to impaired motor performance. Recognition of these secondary effects from a focal lesion is essential for understanding brain-behavior relationships after injury, and they may have important implications for neurorehabilitation.
最近的研究表明，局灶性损伤可能对网络功能产生远程影响，从而影响行为，但这些全网范围的影响还知之甚少。
本研究检验了这样一个假设，即特定于分布式网络流出道的损伤可能导致网络结构完整部分的上游功能障碍。在躯体运动系统中，该上游功能障碍假说预测皮质脊髓束的损伤可能与系统内的功能中断有关。运动障碍可能反映了皮质脊髓损伤和改变的网络功能连接的双重贡献。
共有 23 名亚急性脑卒中患者和 13 名健康对照者参与了这项研究。使用从健康对照者的弥散张量成像生成的束流模板来量化皮质脊髓束损伤。通过静息状态功能磁共振成像来确定躯体运动网络功能完整性。
皮质脊髓损伤的程度与半球间静息功能连接呈负相关，特别是与左侧和右侧中央沟之间的连接呈负相关。尽管皮质脊髓损伤解释了运动表现的大部分变异性，但在皮质脊髓损伤程度较轻或中度的受试者中，静息连接的行为影响更大，而在皮质脊髓损伤程度较重的受试者中则更小。
我们的结果表明，皮质功能连接的功能障碍可能发生在皮质脊髓传出束中断后，并可能导致运动表现受损。从局灶性病变中认识到这些继发效应对于理解损伤后的脑-行为关系至关重要，它们可能对神经康复具有重要意义。
