Journal
CEREBRAL CORTEX
Volume 23, Issue 10, Pages 2337-2346Publisher
OXFORD UNIV PRESS INC
DOI: 10.1093/cercor/bhs233
Keywords
aging; BOLD; CBF; CMRO2; dual-echo ASL; hypercapnia; neural efficiency; processing efficiency
Categories
Funding
- National Institutes of Health [1R01AG029523, R01MH084021]
Ask authors/readers for more resources
The precise mechanisms that give rise to the blood-oxygen-level-dependent (BOLD) activation differences that accompany agerelated cognitive slowing remain fundamentally unknown. We sought to isolate the origin of age-related BOLD changes by comparing blood-flow and oxygen-metabolic constituents of the BOLD response using dual-echo arterial spin labeling during visual stimulation and CO2 ingestion. We hypothesized, and our results confirmed, that age-related changes in the ratio of fractional cerebral blood flow to fractional cerebral metabolic rate of oxygen consumption (Delta CBF/Delta CMRO2) lead to the BOLD changes that are observed in older adults. Delta CBF/Delta CMRO2 was also significantly related to performance, suggesting that age-related cognitive slowing results from neural cell assemblies that operate less efficiently, requiring greater oxygen metabolism that is not matched by blood-flow changes relative to younger adults. Age-related changes in Delta CBF/Delta CMRO2 are sufficient to explain variations in BOLD responding and performance cited throughout the literature, assuming no bias based on physiological baseline CMRO2.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available