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Preserving syntactic processing across the adult life span: the modulation of the frontotemporal language system in the context of age-related atrophy.

Published version
Peer-reviewed

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Type

Article

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Authors

Tyler, Lorraine K 
Shafto, Meredith A 
Randall, Billi 
Wright, Paul 
Marslen-Wilson, William D 

Abstract

Although widespread neural atrophy is an inevitable consequence of normal aging, not all cognitive abilities decline as we age. For example, spoken language comprehension tends to be preserved, despite atrophy in neural regions involved in language function. Here, we combined measures of behavior, functional activation, and gray matter (GM) change in a younger (19-34 years) and older group (49-86 years) of participants to identify the mechanisms leading to preserved language comprehension across the adult life span. We focussed primarily on syntactic functions because these are strongly left lateralized, providing the potential for contralateral recruitment. In an functional magnetic resonance imaging study, we used a word-monitoring task to minimize working memory demands, manipulating the availability of semantics and syntax to ask whether syntax is preserved in aging because of the functional recruitment of other brain regions, which successfully compensate for neural atrophy. Performance in the older group was preserved despite GM loss. This preservation was related to increased activity in right hemisphere frontotemporal regions, which was associated with age-related atrophy in the left hemisphere frontotemporal network activated in the young. We argue that preserved syntactic processing across the life span is due to the shift from a primarily left hemisphere frontotemporal system to a bilateral functional language network.

Description

Keywords

Adult, Aged, Aged, 80 and over, Aging, Atrophy, Brain, Brain Mapping, Dominance, Cerebral, Female, Frontal Lobe, Humans, Image Processing, Computer-Assisted, Language, Language Disorders, Language Tests, Longevity, Magnetic Resonance Imaging, Male, Middle Aged, Nerve Net, Neural Pathways, Speech Perception, Temporal Lobe, Young Adult

Journal Title

Cereb Cortex

Conference Name

Journal ISSN

1047-3211
1460-2199

Volume Title

20

Publisher

Oxford University Press (OUP)
Sponsorship
Medical Research Council (G0500842)
Medical Research Council (G19/27)
Medical Research Council (MC_U105580454)