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Neurosci Biobehav Rev. 2018 Jan;84:134-150. doi: 10.1016/j.neubiorev.2017.11.010. Epub 2017 Nov 26.

Age-related changes in the neural networks supporting semantic cognition: A meta-analysis of 47 functional neuroimaging studies.

Author information

1
Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE) & Department of Psychology, University of Edinburgh, UK. Electronic address: p.hoffman@ed.ac.uk.
2
Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE) & Department of Psychology, University of Edinburgh, UK.

Abstract

Semantic cognition is central to understanding of language and the world and, unlike many cognitive domains, is thought to show little age-related decline. We investigated age-related differences in the neural basis of this critical cognitive domain by performing an activation likelihood estimation (ALE) meta-analysis of functional neuroimaging studies comparing young and older people. On average, young people outperformed their older counterparts during semantic tasks. Overall, both age groups activated similar left-lateralised regions. However, older adults displayed less activation than young people in some elements of the typical left-hemisphere semantic network, including inferior prefrontal, posterior temporal and inferior parietal cortex. They also showed greater activation in right frontal and parietal regions, particularly those held to be involved in domain-general controlled processing, and principally when they performed more poorly than the young. Thus, semantic processing in later life is associated with a shift from semantic-specific to domain-general neural resources, consistent with the theory of neural dedifferentiation, and a performance-related reduction in prefrontal lateralisation, which may reflect a response to increased task demands.

KEYWORDS:

Default mode network; Multiple demand network; Semantic memory; fMRI

PMID:
29183684
DOI:
10.1016/j.neubiorev.2017.11.010
[Indexed for MEDLINE]
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