Guggisberg Adrian G, Honma Susanne M, Findlay Anne M, Dalal Sarang S, Kirsch Heidi E, Berger Mitchel S, Nagarajan Srikantan S
Biomagnetic Imaging Lab, Department of Radiology, University of California San Francisco, San Francisco, CA 94143-0628, USA.
Ann Neurol. 2008 Feb;63(2):193-203. doi: 10.1002/ana.21224.
The spatial distribution of functional connectivity between brain areas and the disturbance introduced by focal brain lesions are poorly understood. Based on the rationale that damaged brain tissue is disconnected from the physiological interactions among healthy areas, this study aimed to map the functionality of brain areas according to their connectivity with other areas.
Magnetoencephalography recordings of spontaneous cortical activity during resting state were obtained from 15 consecutive patients with focal brain lesions and from 14 healthy control subjects. Neural activity in the brain was estimated using an adaptive spatial filtering technique. The mean imaginary coherence between brain voxels was then calculated as an index of functional connectivity.
Imaginary coherence was greatest in the alpha frequency range corresponding to the human cortical idling rhythm. In healthy subjects, functionally critical brain areas such as the somatosensory and language cortices had the highest alpha coherence. When compared with healthy control subjects, all lesion patients had diffuse or scattered brain areas with decreased alpha coherence. Patients with lesion-induced neurological deficits displayed decreased connectivity estimates in the corresponding brain area compared with intact contralateral regions. In tumor patients without preoperative neurological deficits, brain areas showing decreased coherence could be surgically resected without the occurrence of postoperative deficits.
Resting state coherence measured with magnetoencephalography is capable of mapping the functional connectivity of the brain, and can therefore offer valuable information for use in planning resective surgeries in patients with brain lesions, as well as investigations into structural-functional relationships in healthy subjects.
脑区之间功能连接的空间分布以及局灶性脑损伤所引发的干扰目前仍知之甚少。基于受损脑组织与健康区域之间的生理相互作用断开联系这一理论，本研究旨在根据脑区与其他区域的连接情况描绘其功能。
对15例连续性局灶性脑损伤患者及14名健康对照者进行静息状态下自发皮质活动的脑磁图记录。采用自适应空间滤波技术估计脑内神经活动。然后计算脑体素之间的平均虚相干性作为功能连接的指标。
虚相干性在对应于人类皮质静息节律的α频率范围内最大。在健康受试者中，诸如体感和语言皮质等功能关键脑区具有最高的α相干性。与健康对照者相比，所有损伤患者均存在弥漫性或散在性脑区α相干性降低。与完整的对侧区域相比，因损伤导致神经功能缺损的患者在相应脑区的连接估计值降低。在术前无神经功能缺损的肿瘤患者中，显示相干性降低的脑区可在手术切除后不出现术后缺损。
用脑磁图测量的静息状态相干性能够描绘脑功能连接情况，因此可为脑损伤患者的手术切除规划以及健康受试者结构 - 功能关系的研究提供有价值的信息。
