The effect of prolonged glucose infusion on resting-state fMRI signal fluctuations at 7 T

The aim of this study was to examine the effect of 2-h glucose infusion after an overnight fast on relative resting-state fMRI signal fluctuations. Our hypothesis was that neuronal glucose metabolism would be affected, and that this would lead to changes in signal power at specific frequency bands. Resting state fMRI (rsfMRI) scans were acquired in 9 subjects pre- and post-glucose ∼2 h infusion. Fourier spectral analysis was performed using signals localized in the prefrontal cortex. Power spectra were calculated and statistical analysis was performed targeting the full spectral range using both a cluster-based and Wilcoxon signed rank test. For both tests, post-infusion signal power was significantly higher between the 0.015-0.1 Hz range. Moreover we observed differences at higher frequencies, normally attributed to cardiac or respiratory related signals. Our findings suggest that prolonged glucose infusion post-fasting may significantly modulate rsfMRI signal fluctuations in the prefrontal cortex that may be related to metabolic responses to glucose infusion. Future studies should investigate the dynamic effects of sustained glucose infusion using continuous fMRI, exploring implications for brain function and metabolic disorders like diabetes.