1 Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin/London, Germany. garrett@mpib-berlin.mpg.de.
2 Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany. garrett@mpib-berlin.mpg.de.
3 Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin/London, Germany.
4 Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
5 European University Institute, San Domenico di Fiesole (FI), Fiesole, Italy.
6 Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
7 Department of Physics, Concordia University, Montreal, Canada.
8 PERFORM Centre, Concordia University, Montreal, Canada.

Age differences in brain signal variability are robust to multiple vascular controls.

Sci Rep. 2017 08 31;7(1):10149

Authors: Garrett DD, Lindenberger U, Hoge RD, Gauthier CJ

Abstract

A host of studies support that younger, better performing adults express greater moment-to-moment blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in various cortical regions, supporting an emerging view that the aging brain may undergo a generalized reduction in dynamic range. However, the exact physiological nature of age differences in SDBOLD remains understudied. In a sample of 29 younger and 45 older adults, we examined the contribution of vascular factors to age group differences in fixation-based SDBOLD using (1) a dual-echo BOLD/pseudo-continuous arterial spin labeling (pCASL) sequence, and (2) hypercapnia via a computer-controlled gas delivery system. We tested the hypothesis that, although SDBOLD may relate to individual differences in absolute cerebral blood flow (CBF), BOLD cerebrovascular reactivity (CVR), or maximum BOLD signal change (M), robust age differences in SDBOLD would remain after multiple statistical controls for these vascular factors. As expected, our results demonstrated that brain regions in which younger adults expressed higher SDBOLD persisted after comprehensive control of vascular effects. Our findings thus further establish BOLD signal variability as an important marker of the aging brain.

PMID: 28860455 [PubMed - in process]