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Preliminary investigation of hemodynamic fMRI dynamics in aging

Poster Session E - Monday, March 9, 2026, 2:30 – 4:30 pm PDT, Fairview/Kitsilano Ballroom

Claire J Ciampa¹ (), Ian C Ballard², Anne S Berry¹; ¹Brandeis University, ²University of California, Riverside

Recent evidence from young adults suggests that the timing of the fMRI blood-oxygen-level-dependent (BOLD) signal in the nucleus accumbens (NAcc) is associated with underlying dopamine physiology. We tested whether these results extend to healthy older adults using n=46 participants (60-82 years old, 52% female) who completed two simultaneous PET/fMRI scans with the tracer [11C]raclopride to measure dopamine D2/3 receptor density and resting state fMRI scans to measure hemodynamic latency (blood flow timing). Each participant underwent separate scans on placebo and 20mg oral methylphenidate to enhance dopamine availability. Consistent with previous work, we found that the ventral striatum (VST), which includes NAcc, exhibited higher latency compared with dorsal caudate (DCA; p=.003) and trending higher latency compared with dorsal putamen (DPUT; p=.07). Past work has shown that while there is no effect of a dopamine drug on latency, individual differences in VST [11C]raclopride predict drug-related changes in VST latency. We demonstrate similar findings: there was no direct effect of drug on VST latency (p=.51), but higher VST [11C]raclopride was associated with greater drug-related decreases in VST latency (p=.03), indicating that hemodynamic latency is sensitive to underlying components of dopamine function. We did not find relationships between VST latency and memory performance on a reward-motivated encoding task (p=.32). These results extend work in young adults to demonstrate that VST hemodynamic latency may be a useful and easily obtainable measure of dopamine function in older adults. Future work will consider cerebrovascular factors such as white matter hyperintensities, which may influence blood flow.

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