Both young and older adults recruited the ventromedial prefrontal cortex to support prototype-based generalization, and engagement of the VMPFC prototype-learning system may help maintain concept generalization in older adults despite age-related memory declines.
Key Findings
Results
Older adults were more likely than young adults to be best fit by the prototype model and less likely to be best fit by the exemplar model.
Young and older adults completed a prototype-based category learning task while undergoing fMRI.
Formal prototype and exemplar models were fit to behavioral and brain data to index concept learning based on abstraction versus memory for individual category members.
The fit of both models to behavior was poorer in older adults compared to young adults.
Despite poorer overall model fit, older adults showed a relative shift toward prototype-based strategies compared to young adults.
Results
Only young adults showed significant prototype-tracking in the hippocampus, whereas older adults did not.
Neural prototype and exemplar model fitting was applied to fMRI brain data.
Hippocampal prototype-tracking was significant in young adults but not in older adults.
This finding is consistent with known age-related declines in episodic memory and hippocampal function.
The hippocampus is associated with memory for individual instances (exemplar-based learning), and its reduced engagement in older adults aligns with reduced exemplar model fit in that group.
Results
Both young and older adults recruited the ventromedial prefrontal cortex (VMPFC) to support prototype-based generalization.
VMPFC showed significant prototype-tracking in both age groups.
Evidence for age differences in prototype representations were weak in the VMPFC specifically.
This contrasts with hippocampal findings, where age differences were more pronounced.
The VMPFC prototype-learning system appeared to be preserved in older adults relative to hippocampal contributions.
Results
A whole-brain analysis revealed evidence for age differences in prototype representations, but these differences were weak in the VMPFC and hippocampus specifically.
Whole-brain analysis identified regions showing age-related differences in prototype tracking.
Despite whole-brain age differences, regional analysis of VMPFC and hippocampus showed only weak evidence for age differences.
This dissociation suggests that certain core concept-learning regions may be relatively preserved with age.
The authors used formal model comparison to distinguish prototype- from exemplar-based neural representations.
Discussion
Engagement of the VMPFC prototype-learning system may help maintain concept generalization in older adults despite age-related declines in episodic memory.
Older age has been associated with declines in the ability to remember individual instances.
The VMPFC supports abstraction and prototype-based representations across both age groups.
The authors propose that preserved VMPFC function compensates for reduced hippocampal contributions to category learning in older adults.
Prototype-based category learning was used as the domain to test age differences in concept learning and generalization.