Precommissural and postcommissural fornix microstructure in healthy aging and cognition

Coad, Bethany ORCID: https://orcid.org/0000-0002-9267-244X, Craig, Emma, Louch, Rebecca, Aggleton, John ORCID: https://orcid.org/0000-0002-5573-1308, Vann, Seralynne ORCID: https://orcid.org/0000-0002-6709-8773 and Metzler-Baddeley, Claudia ORCID: https://orcid.org/0000-0002-8646-1144 2020. Precommissural and postcommissural fornix microstructure in healthy aging and cognition. Brain and Neuroscience Advances 4 , pp. 1-12. 10.1177/2398212819899316

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Abstract

The fornix is a key tract of the hippocampal formation, whose status is presumed to contribute to age-related cognitive decline. The precommissural and postcommissural fornix subdivisions form respective basal forebrain/frontal and diencephalic networks that may differentially affect aging and cognition. We employed multi-parametric magnetic resonance imaging (MRI) including neurite orientation density and dispersion imaging, quantitative magnetization transfer (qMT), and T1-relaxometry MRI to investigate the microstructural properties of these fornix subdivisions and their relationship with aging and cognition in 149 asymptomatic participants (38–71 years). Aging was associated with increased free water signal and reductions in myelin-sensitive R1 and qMT indices but no apparent axon density differences in both precommissural and postcommissural fibers. Precommissural relative to postcommissural fibers showed a distinct microstructural pattern characterised by larger free water signal and axon orientation dispersion, with lower apparent myelin and axon density. Furthermore, differences in postcommissural microstructure were related to performance differences in object-location paired-associate learning. These results provide novel in vivo neuroimaging evidence for distinct microstructural properties of precommissural and postcommissural fibers that are consistent with their anatomy as found in axonal tracer studies, as well as for a contribution of postcommissural fibers to the learning of spatial configurations.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Cardiff University Brain Research Imaging Centre (CUBRIC) Psychology
Publisher:	SAGE Publications
ISSN:	2398-2128
Funders:	Wellcome Trust
Date of First Compliant Deposit:	25 February 2020
Date of Acceptance:	11 December 2019
Last Modified:	07 Nov 2023 11:16
URI:	https://orca.cardiff.ac.uk/id/eprint/127491

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