http://www.nitrc.org/forum/forum.php?forum_id=6122 <table border="0" width="100%"><tr><td align="left"/></tr></table> <p><b>The whole-brain "global" signal from resting state fMRI as a potential biomarker of quantitative state changes in glucose metabolism.</b></p> <p>Brain Connect. 2016 Mar 31;</p> <p>Authors: Thompson GJ, Riedl V, Grimmer T, Drzezga A, Herman P, Hyder F</p> <p>Abstract<br/> The evolution of functional magnetic resonance imaging to resting-state (R-fMRI) allows measurement of changes in brain networks attributed to state changes, such as in neuropsychiatric diseases versus healthy controls. Since these networks are observed by comparing normalized R-fMRI signals, it is difficult to determine the metabolic basis of such group differences. To investigate the metabolic basis of R-fMRI network differences within a normal range, eyes open versus eyes closed in healthy human subjects was used. R-fMRI was recorded simultaneously with fluoro-deoxyglucose positron emission tomography (FDG-PET). Higher baseline FDG was observed in the eyes open state. Variance-based metrics calculated from R-fMRI did not match the baseline shift in FDG. Functional connectivity density (FCD) based metrics showed a shift similar to the baseline shift of FDG, however, this was lost if R-fMRI "nuisance signals" were regressed prior to FCD calculation. Average correlation with the mean R-fMRI signal across the whole brain, generally regarded as a "nuisance signal," also showed a shift similar to the baseline of FDG. Thus, despite lacking a baseline itself, changes in whole-brain correlation may reflect changes in baseline brain metabolism. Conversely, variance-based metrics may remain similar between states due to inherent region-to-region differences overwhelming the differences between normal physiological states. As most previous studies have excluded the spatial means of R-fMRI metrics from their analysis, this work presents the first evidence of a potential R-fMRI biomarker for baseline shifts in quantifiable metabolism between brain states.<br/> </p><p>PMID: 27029438 [PubMed - as supplied by publisher]</p> en-us Copyright 2000-2026 NITRC OSI Mon, 04 May 2026 18:50:29 GMT http://blogs.law.harvard.edu/tech/rss NITRC RSS generator