Ventromedial prefrontal cortex supports prototype representations in healthy older adults

Area of Science:

• Cognitive Neuroscience
• Neuroimaging
• Human Aging Research

Background:

• Concept learning and generalization are crucial throughout life, yet age-related memory declines may impact these abilities.
• Little is known about how aging affects concept learning, generalization, and the underlying neural mechanisms.

Purpose of the Study:

• To investigate age differences in concept learning using a prototype-based category learning task.
• To examine how young and older adults learn concepts via abstraction versus memory for individual instances.
• To identify neural systems supporting concept generalization in aging.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to study young and older adults during a category-learning task.
• Prototype and exemplar models were fitted to behavioral and brain data to differentiate abstraction from instance memory.
• Neural activity was analyzed to identify brain regions involved in prototype-based generalization.

Main Results:

• Model fits to behavior were poorer in older adults, who were more likely to be best fit by the prototype model.
• Young adults showed hippocampus activity for prototype tracking, while both age groups recruited the ventromedial prefrontal cortex (VMPFC).
• Whole-brain analysis revealed age differences in prototype representations, though less pronounced in the VMPFC and hippocampus.

Conclusions:

• Older adults may shift towards more abstract, prototype-based concept learning strategies.
• The VMPFC's role in prototype learning may be preserved in aging, potentially supporting concept generalization.
• Engagement of the VMPFC may help older adults maintain concept generalization abilities despite age-related cognitive changes.