近日，德国慕尼黑工业大学教授Valentin Riedl及其团队的论文发现了BOLD信号的改变会阻碍人体皮层的氧代谢。2025年12月16日，国际知名学术期刊《自然—神经科学》发表了这一成果。

在这里，研究团队发现在各种任务中，大约40%具有显著BOLD信号变化的体素表现出反向的氧代谢，特别是在默认模式网络中。这些“不协调”体素在基线氧提取分数和通过氧提取分数变化调节的需氧量方面存在差异，而“协调”体素主要依赖于脑血流变化。他们的研究结果挑战了对BOLD信号的规范解释，表明定量功能磁共振成像可以更可靠地评估神经元活动的绝对和相对变化。

据悉，功能性磁共振成像通过监测血氧水平的变化间接测量大脑活动，被称为血氧水平依赖（BOLD）信号，而不是直接测量神经元活动。这种方法主要依赖于神经血管耦合，即将神经元活动与脑血流变化联系起来的机制。然而，目前尚不清楚这种关系是否与人类皮层的阳性和阴性BOLD反应一致。

附：英文原文

Title: BOLD signal changes can oppose oxygen metabolism across the human cortex

Author: Epp, Samira M., Castrilln, Gabriel, Yuan, Beijia, Andrews-Hanna, Jessica, Preibisch, Christine, Riedl, Valentin

Issue&Volume: 2025-12-16

Abstract: Functional magnetic resonance imaging measures brain activity indirectly by monitoring changes in blood oxygenation levels, known as the blood-oxygenation-level-dependent (BOLD) signal, rather than directly measuring neuronal activity. This approach crucially relies on neurovascular coupling, the mechanism that links neuronal activity to changes in cerebral blood flow. However, it remains unclear whether this relationship is consistent for both positive and negative BOLD responses across the human cortex. Here we found that about 40% of voxels with significant BOLD signal changes during various tasks showed reversed oxygen metabolism, particularly in the default mode network. These ‘discordant’ voxels differed in baseline oxygen extraction fraction and regulated oxygen demand via oxygen extraction fraction changes, whereas ‘concordant’ voxels depended mainly on cerebral blood flow changes. Our findings challenge the canonical interpretation of the BOLD signal, indicating that quantitative functional magnetic resonance imaging provides a more reliable assessment of both absolute and relative changes in neuronal activity.

DOI: 10.1038/s41593-025-02132-9

Source: https://www.nature.com/articles/s41593-025-02132-9