TY - JOUR T1 - Causal influences of brain metabolic activity reveal interregional progressions in normal aging JF - bioRxiv DO - 10.1101/490292 SP - 490292 AU - Xin Di AU - Marie Wölfer AU - Mario Amend AU - Hans Wehrl AU - Tudor M. Ionescu AU - Bernd J. Pichler AU - Bharat B. Biswal AU - the Alzheimer’s Disease Neuroimaging Initiative Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/12/22/490292.abstract N2 - During healthy brain aging, different brain regions show anatomical or functional declines or compensatory increases at different rates. However, few studies have explored the interregional causal influences during the aging process. We proposed a causality analysis framework combining high dimensionality independent component analysis (ICA), Granger causality, and LASSO (least absolute shrinkage and selection operator) regression on longitudinal brain metabolic activity data measured by Fludeoxyglucose positron emission tomography (FDG-PET). We analyzed FDG-PET images from healthy elderly subjects, who were scanned at least five sessions with an averaged intersession interval of about one year. The longitudinal data were concatenated across subjects to form a time series, and the first order autoregressive model was used to measure interregional causality among the independent sources of metabolic activity identified using ICA. Several independent sources with reduced metabolic activity in aging, including the anterior temporal lobe, orbital frontal cortex, anterior insula, and inferior parietal lobule, demonstrated causal influences over many other widespread brain regions, where themselves showed smaller age related declines. The current data demonstrated interregional progressions of aging on metabolic activity at the scale of a year, and demonstrated key brain regions in the aging process that have strong influences over other regions. ER -