Feedback-Based Learning In Aging: Contributions And Trajectories Of Change In Striatal And Hippocampal Systems

Keywords

Aging; fMRI; Hippocampus; Learning; Memory; Striatum

Abstract

The striatum supports learning from immediate feedback by coding prediction errors (PEs), whereas the hippocampus (HC) plays a parallel role in learning from delayed feedback. Both regions show evidence of decline in human aging, but behavioral research suggests greater decline in HC versus striatal functions. The present study included male and female humans and used fMRI to examine younger and older adults’ brain activation patterns during a learning task with choice feedback presented immediately or after a brief delay. Participants then completed a surprise memory task that tested their recognition of trial-unique feedback stimuli, followed by assessments of postlearning cue preference, outcome probability awareness, and willingness to pay. The study yielded three main findings. First, behavioral measures indicated similar rates of learning in younger and older adults across conditions, but postlearning measures indicated impairment in older adults’ ability to subsequently apply learning to discriminate between cues. Second, PE signals in the striatum were greater for immediate versus delayed feedback in both age groups, but PE signals in the HC were greater for delayed versus immediate feedback only in younger adults. Third, unlike younger adults, older adults failed to exhibit enhanced episodic memory for outcome stimuli in the delayed-feedback condition. Together, these findings indicate that HC circuits supporting learning and memory decline more than striatal circuits in healthy aging, which suggests that declines in HC learning signals may be an important predictor of deficits in learning-dependent economic decisions among older adults.

Publication Date

9-26-2018

Publication Title

Journal of Neuroscience

Volume

38

Issue

39

Number of Pages

8453-8462

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1523/JNEUROSCI.0769-18.2018

Socpus ID

85054153083 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85054153083

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