State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China.
J Neurosci. 2012 Jan 11;32(2):481-9. doi: 10.1523/JNEUROSCI.1953-11.2012.
Conceptual processing is a crucial brain function for humans. Past research using neuropsychological and task-based functional brain-imaging paradigms indicates that widely distributed brain regions are related to conceptual processing. Here, we explore the potential contribution of intrinsic or spontaneous brain activity to conceptual processing by examining whether resting-state functional magnetic resonance imaging (rs-fMRI) signals can account for individual differences in the conceptual processing efficiencies of healthy individuals. We acquired rs-fMRI and behavioral data on object conceptual processing tasks. We found that the regional amplitude of spontaneous low-frequency fluctuations in the blood oxygen level-dependent signal in the left (posterior) middle temporal gyrus (LMTG) was highly correlated with participants' semantic processing efficiency. Furthermore, the strength of the functional connectivity between the LMTG and a series of brain regions-the left inferior frontal gyrus, bilateral anterior temporal lobe, bilateral medial temporal lobe, posterior cingulate gyrus, and ventromedial and dorsomedial prefrontal cortices-also significantly predicted conceptual behavior. The regional amplitude of low-frequency fluctuations and functionally relevant connectivity strengths of LMTG together accounted for 74% of individual variance in object conceptual performance. This semantic network, with the LMTG as its core component, largely overlaps with the regions reported in previous conceptual/semantic task-based fMRI studies. We conclude that the intrinsic or spontaneous activity of the human brain reflects the processing efficiency of the semantic system.
概念处理是人类大脑的一项关键功能。过去使用神经心理学和基于任务的功能脑成像范式的研究表明，广泛分布的大脑区域与概念处理有关。在这里，我们通过检查静息态功能磁共振成像 (rs-fMRI) 信号是否可以解释健康个体概念处理效率的个体差异，来探索内在或自发脑活动对概念处理的潜在贡献。我们采集了对象概念处理任务的 rs-fMRI 和行为数据。我们发现，左侧（后）颞中回（LMTG）血氧水平依赖信号的自发低频波动的区域幅度与参与者的语义处理效率高度相关。此外，LMTG 与一系列大脑区域（左侧额下回、双侧颞叶前区、双侧颞叶内侧回、后扣带回、腹侧和背侧前额叶皮质）之间的功能连接强度也显著预测了概念行为。LMTG 的低频波动的区域幅度和功能相关连接强度共同解释了对象概念表现个体差异的 74%。这个语义网络以 LMTG 为核心组成部分，与之前基于概念/语义任务的 fMRI 研究中报告的区域有很大的重叠。我们得出结论，人脑的内在或自发活动反映了语义系统的处理效率。
