Facca Massimiliano, Ridolfo Anna, Celli Miriam, Tarricone Claudia, Mazzonetto Ilaria, Volpi Tommaso, Vlassenko Andrei G, Goyal Manu S, Corbetta Maurizio, Bertoldo Alessandra
Padova Neuroscience Center (PNC), University of Padova (Unipd), Padova, Italy.
Department of Information Engineering, University of Padova (Unipd), Padova, Italy.
bioRxiv. 2025 Jul 30:2025.07.29.667370. doi: 10.1101/2025.07.29.667370.
Intrinsic brain activity is characterized by pervasive long-range temporal correlations. While these scale-invariant dynamics are a fundamental hallmark of brain function, their implications for individual-level metabolic regulation remain poorly understood. Here, we address this gap by integrating resting-state functional Magnetic Resonance Imaging (fMRI) and dynamic [F]FDG Positron Emission Tomography (PET) data acquired from the same cohort of participants. We uncover a systematic relationship between long-range temporal correlations, quantified via the Hurst exponent, and glucose metabolism. Our findings reveal that persistent temporal dependencies impose a measurable metabolic cost, with brains exhibiting higher long-range temporal correlations incurring greater energetic demands. Beyond glucose metabolism, we also show that these dynamics are likely supported by continuous biosynthetic processes, such as protein synthesis, which are critical for neural circuit maintenance and remodeling. Overall, our results suggest that a significant fraction of the brain's so-called "Dark Energy" is actively spent to power spontaneous long-range temporal correlations.
大脑内在活动的特征是普遍存在的长程时间相关性。虽然这些尺度不变的动力学是脑功能的一个基本标志，但它们对个体水平代谢调节的影响仍知之甚少。在这里，我们通过整合来自同一组参与者的静息态功能磁共振成像（fMRI）和动态[F]FDG正电子发射断层扫描（PET）数据来填补这一空白。我们发现通过赫斯特指数量化的长程时间相关性与葡萄糖代谢之间存在系统关系。我们的研究结果表明，持续的时间依赖性会带来可测量的代谢成本，大脑表现出更高的长程时间相关性会产生更大的能量需求。除了葡萄糖代谢，我们还表明这些动力学可能由连续的生物合成过程支持，如蛋白质合成，这对神经回路的维持和重塑至关重要。总体而言，我们的结果表明，大脑所谓的“暗能量”中有很大一部分被积极用于为自发的长程时间相关性提供动力。
