title: Blood oxygen level-dependent signal variability is more than just noise.
abstract: Functional magnetic resonance imaging (fMRI) research often attributes blood oxygen level-dependent (BOLD) signal variance to measurement-related confounds. However, what is typically considered "noise" variance in data may be a vital feature of brain function. We examined fMRI signal variability during fixation baseline periods, and then compared SD- and mean-based spatial patterns and their relations with chronological age (20-85 years). We found that not only was the SD-based pattern robust, it differed greatly, both spatially and statistically, from the mean-based pattern. Notably, the unique age-predictive power of the SD-based pattern was more than five times that of the mean-based pattern. This reliable SD-based pattern of activity highlights an important "signal" within what is often considered measurement-related "noise." We suggest that examination of BOLD signal variability may reveal a host of novel brain-related effects not previously considered in neuroimaging research.
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, Ontario M6A 2E1, Canada. d.garrett@utoronto.ca
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Garrett
authors.forename: Natasa
authors.initials: N
authors.lastname: Kovacevic
authors.forename: Anthony R
authors.initials: AR
authors.lastname: McIntosh
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Grady
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000378:metabolism; D004560:Electricity / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D010100:Oxygen