Greater BOLD Variability is Associated With Poorer Cognitive Function in an Adult Lifespan Sample

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 31; no. 1; pp. 562 - 574
• Main Authors: Boylan, Maria A, Foster, Chris M, Pongpipat, Ekarin E, Webb, Christina E, Rodrigue, Karen M, Kennedy, Kristen M
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.01.2021
• Subjects: Adult; Aged; Aged, 80 and over; Aging - physiology; Brain - physiopathology; Cognition - physiology; Female; Gyrus Cinguli - physiopathology; Humans; Longevity - physiology; Magnetic Resonance Imaging - methods; Male; Memory Disorders - physiopathology; Memory, Short-Term - drug effects; Memory, Short-Term - physiology; Middle Aged; Original; Young Adult; fMRI; back; MSSD; aging; working memory; n-back
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhaa243

Abstract Moment-to-moment fluctuations in brain signal assessed by functional magnetic resonance imaging blood oxygenation level dependent (BOLD) variability is increasingly thought to represent important “signal” rather than measurement-related “noise.” Efforts to characterize BOLD variability in healthy aging have yielded mixed outcomes, demonstrating both age-related increases and decreases in BOLD variability and both detrimental and beneficial associations. Utilizing BOLD mean-squared-successive-differences (MSSD) during a digit n-back working memory (WM) task in a sample of healthy adults (aged 20–94 years; n = 171), we examined effects of aging on whole-brain 1) BOLD variability during task (mean condition MSSD across 0–2–3-4 back conditions), 2) BOLD variability modulation to incrementally increasing WM difficulty (linear slope from 0–2–3-4 back), and 3) the association of age-related differences in variability with in- and out-of-scanner WM performance. Widespread cortical and subcortical regions evidenced increased mean variability with increasing age, with no regions evidencing age-related decrease in variability. Additionally, posterior cingulate/precuneus exhibited increased variability to WM difficulty. Notably, both age-related increases in BOLD variability were associated with significantly poorer WM performance in all but the oldest adults. These findings lend support to the growing corpus suggesting that brain-signal variability is altered in healthy aging; specifically, in this adult lifespan sample, BOLD-variability increased with age and was detrimental to cognitive performance.