Dissociable contributions of cortical thickness and surface area to cognitive aging: evidence from multiple longitudinal cohorts
Year: 2026
Type: article
Study design: Observational Study
Abstract: Cortical volume, a widely-used marker of brain ageing, is the product of two genetically and developmentally dissociable morphometric features: thickness and area. However, it remains unclear whether these two features have dissociable consequences for cognitive ageing. To address this, we analyse cross-sectional and longitudinal neuroimaging and cognitive data from one discovery cohort (Cam-CAN) and two independent, pre-registered replication cohorts (OASIS-3 and HABS-HD), leveraging wide age ranges across adulthood, different follow-up intervals and diverse population backgrounds. We show that thickness declines more steeply with age than does area, and shows stronger associations with longitudinal change in fluid cognitive abilities, fairly uniformly across the cortex. Cognitive change is also dependent on baseline thickness, independent of thickness change and independent of baseline cognitive ability. In contrast, area is comparatively stable across adulthood, at least until old age, and shows weaker and more heterogeneous associations with cognitive change, despite being a stronger mediator of the effect of polygenic scores on baseline cognitive ability. Together, these findings help to reconcile inconsistencies in the literature, and indicate that thickness provides a more sensitive marker of dynamic neurobiological processes underlying cognitive ageing, whereas area seems to reflect primarily stable, trait-like variation in cognitive ability.
Source: Cerebral Cortex
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $5,038
Funders: European Commission, National Institutes of Health, Directorate for Biological Sciences, Medical Research Council, Biotechnology and Biological Sciences Research Council, National Institute on Aging, National Institute of Neurological Disorders and Stroke, National Institute of Biomedical Imaging and Bioengineering
Awards: Healthy minds from 0-100 years: Optimising the use of European brain imaging cohorts, G1643978601, G3275562924, G3594153814, Systems Cognitive Neuroscience of Healthy Ageing: Population-Representative Studies of Functional Plasticity and Neural Change, Health Disparities in Alzheimer's Disease and Mild Cognitive Impairment among Mexican Americans, DRIVING PERFORMANCE IN PRECLINICAL ALZHEIMER'S DISEASE, Healthy Aging and Senile Dementia, Washington University Institute of Clinical and Translational Sciences, G7831108753, G7847862906, NINDS CENTER CORE FOR BRAIN IMAGING, Laboratory of Neuro Imaging Resource (LONIR), G9000112288, G9000115080, Health and Aging Brain among Latino Elders (HABLE-AT(N)) Study, Alzheimer's Disease Research Center, Epigenetic Risk Factors for AD Age at Onset and Health Disparities: HABLE Epigenetics Study, THE XNAT IMAGING INFORMATICS PLATFORM, The Health & Aging Brain Study - Health Disparities (HABS-HD), Antecedent Biomarkers for Alzheimer Disease: The Adult Children Study
OpenAlex ID: W7140041764