Reconfiguration of functional brain networks and metabolic cost converge during task performance

The ability to solve cognitive tasks depends upon adaptive changes in the organization of whole-brain functional networks. However, the link between task-induced network reconfigurations and their underlying energy demands is poorly understood. We address this by multimodal network analyses integrating functional and molecular neuroimaging acquired concurrently during a complex cognitive task. Task engagement elicited a marked increase in the association between glucose consumption and functional brain network reorganization. This convergence between metabolic and neural processes was specific to feedforward connections linking the visual and dorsal attention networks, in accordance with task requirements of visuo-spatial reasoning. Further increases in cognitive load above initial task engagement did not affect the relationship between metabolism and network reorganization but only modulated existing interactions. Our findings show how the upregulation of key computational mechanisms to support cognitive performance unveils the complex, interdependent changes in neural metabolism and neuro-vascular responses.

Methods
Data of 22 healthy human participants was collected using simultaneous PET/MR imaging at rest and during task performance (easy and hard level).

Data are processed and include individual brain maps in MNI-space of glucose metabolism, cerebral blood flow, BOLD task effects and functional connectivity. Individual DCM results from BOLD imaging are provided.

Group results include separate one-sample t-tests for each imaging modality. The conjunction map represents the intersection of group task effects (hard level) across glucose metabolism, cerebral blood flow and BOLD changes.

Data are fully anonymized.

解决认知任务的能力依赖于全脑功能网络组织的适应性重塑。然而，任务诱导的网络重构与其潜在能量需求之间的关联机制仍未得到充分阐明。本研究通过整合复杂认知任务期间同步采集的功能与分子神经影像学数据开展多模态网络分析，对这一问题进行了探究。任务参与状态显著增强了葡萄糖代谢与全脑功能网络重构之间的关联。根据视觉空间推理的任务要求，这种代谢与神经过程的特异性汇聚仅存在于连接视觉网络与背侧注意网络的前馈通路中。在初始任务参与基础上进一步提升认知负荷，并未改变代谢与网络重构之间的关联，仅对已存在的交互作用进行了调节。本研究结果揭示了支持认知表现的关键计算机制上调如何展现出神经代谢与神经血管反应间复杂且相互依赖的动态变化。

方法
本研究通过静息态与任务执行（简单难度与困难难度）阶段的同步正电子发射断层扫描/磁共振（PET/MR）成像，采集了22名健康人类受试者的数据。

数据已完成预处理，包含蒙特利尔神经学研究所（MNI）空间下的个体脑图谱，涵盖葡萄糖代谢、脑血流量、血氧依赖水平（Blood Oxygenation Level-Dependent, BOLD）任务效应与功能连接指标。同时提供基于BOLD成像得到的个体动态因果模型（Dynamic Causal Modeling, DCM）结果。

组水平分析结果包含针对每种成像模态的独立单样本t检验。联合图谱反映了组水平任务效应（困难难度）在葡萄糖代谢、脑血流量与BOLD信号变化三者间的交集区域。

所有数据均已完成完全匿名化处理。