Aging Affects Dopaminergic Neural Mechanisms of Cognitive Flexibility
Aging is accompanied by profound changes in the brain’s dopamine system that affect cognitive function. Evidence of powerful individual differences in cognitive aging has sharpened focus on identifying biological factors underlying relative preservation versus vulnerability to decline. Dopamine represents a key target in these efforts. Alterations of dopamine receptors and dopamine synthesis are seen in aging, with receptors generally showing reduction and synthesis demonstrating increases. Using the PET tracer 6-[ 18F]fluoro-L- m-tyrosine, we found strong support for upregulated striatal dopamine synthesis capacity in healthy older adult humans free of amyloid pathology, relative to young people. We next used fMRI to define the functional impact of elevated synthesis capacity on cognitive flexibility, a core component of executive function. We found clear evidence in young adults that low levels of synthesis capacity were suboptimal, associated with diminished cognitive flexibility and altered frontoparietal activation relative to young adults with highest synthesis values. Critically, these relationships between dopamine, performance, and activation were transformed in older adults with higher synthesis capacity. Variability in synthesis capacity was related to intrinsic frontoparietal functional connectivity across groups, suggesting that striatal dopamine synthesis influences the tuning of networks underlying cognitive flexibility. Altogether, these findings define striatal dopamine’s association withmore »
- Authors:
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[1]
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- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Univ. of California, Berkeley, CA (United States)
- Publication Date:
- Grant/Contract Number:
- AC02-05CH11231
- Type:
- Accepted Manuscript
- Journal Name:
- Journal of Neuroscience
- Additional Journal Information:
- Journal Volume: 36; Journal Issue: 50; Journal ID: ISSN 0270-6474
- Publisher:
- Society for Neuroscience
- Research Org:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Org:
- National Institutes of Health (NIH); USDOE
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 60 APPLIED LIFE SCIENCES; aging; cognitive flexibility; dopamine; fMRI; PET; task switching
- OSTI Identifier:
- 1379613
- Free Publicly Accessible Full Text
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Accepted Manuscript (DOE)
- Publisher's Version of Record
- https://doi.org/10.1523/JNEUROSCI.0626-16.2016