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Reduced semantic control in older adults is linked to intrinsic DMN connectivity.

Krieger-Redwood, Katya and Wang, Hao-Ting and Poerio, Giulia L and Martinon, Léa M and Riby, Leigh M and Smallwood, Jonathan and Jefferies, Elizabeth (2019) 'Reduced semantic control in older adults is linked to intrinsic DMN connectivity.' Neuropsychologia, 132. p. 107133. ISSN 0028-3932

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Ageing provides an interesting window into semantic cognition: while younger adults generally outperform older adults on many cognitive tasks, knowledge continues to accumulate over the lifespan and consequently, the semantic store (i.e., vocabulary size) remains stable (or even improves) during healthy ageing. Semantic cognition involves the interaction of at least two components - a semantic store and control processes that interact to ensure efficient and context-relevant use of representations. Given older adults perform less well on tasks measuring executive control, their ability to access the semantic store in a goal driven manner may be compromised. Older adults also consistently show reductions in intrinsic brain connectivity, and we examined how these brain changes relate to age-related changes in semantic performance. We found that while older participants outperformed their younger counterparts on tests of vocabulary size (i.e., NART), younger participants were faster and more accurate in tasks requiring semantic control, and these age differences correlated with measures of intrinsic connectivity between the anterior temporal lobe (ATL) and medial prefrontal cortex (mPFC), within the default mode network. Higher intrinsic connectivity from right ATL to mPFC at rest related to better performance on verbal (but not picture) semantic tasks, and older adults showed an exaggerated version of this pattern, suggesting that this within-DMN connectivity may become more important for conceptual access from words as we age. However, this appeared to be at the expense of control over semantic retrieval - there was little relationship between connectivity and performance for strong associations in either group, but older adults with stronger connectivity showed particularly inefficient retrieval of weak associations. Older adults may struggle to harness the default mode network to support demanding patterns of semantic retrieval, resulting in a performance cost.

Item Type: Article
Uncontrolled Keywords: Cerebral Cortex; Nerve Net; Humans; Magnetic Resonance Imaging; Language; Association; Mental Recall; Aging; Semantics; Aged; Aged, 80 and over; Middle Aged; Female; Male; Executive Function; Connectome
Divisions: Faculty of Science and Health
Faculty of Science and Health > Psychology, Department of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 06 Aug 2021 07:18
Last Modified: 18 Aug 2022 13:12

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