Age-Related Neural Dedifferentiation Is Driven by Declining Reliability
Year: 2026
Type: preprint
Study design: Observational Study
Abstract: Neural dedifferentiation, characterized by reduced distinctiveness of neural representations, is a robust feature of cognitive aging. Multivoxel pattern analyses often operationalize neural distinctiveness as the difference between within-category similarity (reliability) and between-category similarity (confusability). However, it remains unclear whether age-related reductions in distinctiveness are driven by decreases in reliability, increases in confusability, or both, and whether these components demonstrate similar longitudinal trajectories. Using cross-sectional and longitudinal data from the Michigan Neural Distinctiveness (MiND) study, we decomposed distinctiveness into its two components across visual, auditory, and motor cortex in more than 200 young (18-29 years) and older adults (65-94 years) and estimated cross-sectional between-person age differences and longitudinal within-person change simultaneously in mixed-effects models. We found that reliability was lower in older vs. younger adults cross-sectionally, and this reduction was significantly larger than the corresponding effect on confusability. Moreover, reliability also declined longitudinally within individuals across a mean interval of four years. These findings indicate that age-related dedifferentiation is driven primarily by declining reliability rather than increasing confusability, and that reporting distinctiveness alone can conceal substantial age-related change in its components. Keywords: Dedifferentiation, distinctiveness, reliability, confusability, aging, longitudinal study
Source: PsyArXiv (OSF Preprints)
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7223446058