The relationship between age, neural differentiation, and memory performance

Koen, Joshua D., Hauck, Nedra and Rugg, Michael D. (2019) The relationship between age, neural differentiation, and memory performance. The Journal of Neuroscience, 39 (1). pp. 149-162. ISSN 0270-6474

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Healthy aging is associated with decreased neural selectivity (dedifferentiation) in category-selective cortical regions. This finding has prompted the suggestion that dedifferentiation contributes to age-related cognitive decline. Consistent with this possibility, dedifferentiation has been reported to negatively correlate with fluid intelligence in older adults. Here, we examined whether dedifferentiation is associated with performance in another cognitive domain — episodic memory — that is also highly vulnerable to aging. Given the proposed role of differentiation in age-related cognitive decline, we predicted there would be a stronger link between dedifferentiation and episodic memory performance in older than in younger adults. Young (18-30 yrs) and older (64-75 yrs) male and female humans underwent fMRI scanning while viewing images of objects and scenes prior to a subsequent recognition memory test. We computed a differentiation index in two regions-of-interest (ROIs): parahippocampal place area (PPA) and lateral occipital complex (LOC). This index quantified the selectivity of the BOLD response to an ROI's preferred versus non-preferred category (scenes for PPA, objects for LOC). The differentiation index in the PPA, but not the LOC, was lower in older than in younger adults. Additionally, the PPA differentiation index predicted recognition memory performance for the studied items. This relationship was independent of and not moderated by age. The PPA differentiation index also predicted performance on a latent ‘fluency’ factor derived from a neuropsychological test battery; this relationship was also age invariant. These findings suggest that two independent factors, one associated with age, and the other with cognitive performance, drive neural differentiation.

Item Type: Article
Faculty \ School: Faculty of Social Sciences > School of Psychology
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Depositing User: LivePure Connector
Date Deposited: 12 Nov 2018 16:30
Last Modified: 18 Mar 2020 02:12
DOI: 10.1523/JNEUROSCI.1498-18.2018

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