• No association between plasma NfL and default network connectivity in older adults. • Higher plasma NfL linked to smaller hippocampi in cognitively impaired older adults. • Higher plasma NfL linked to lower memory score in cognitively impaired older adults. Plasma neurofilament light chains (pNfL) have shown promise as a biomarker for tracking and predicting neurodegeneration, such as cortical atrophy and hypometabolism, in Alzheimer’s Disease (AD). However, it is still not clear whether neurofilament light chains (NfL) also reflect alterations in the functional connectivity (FC) of the default mode network (DMN), a functional network showing alterations in earlier stages of AD. In this cross-sectional study including 62 cognitively unimpaired (CU) and 47 cognitively impaired (CI) older adults likely due to AD, we measured FC in the posterior midline DMN, and its FC with frontal DMN, temporoparietal DMN, and hippocampus. We also examined whether the previously observed relationships between pNfL and hippocampal volume, as well as memory function, are replicated in our dataset. pNfL showed no association with DMN FC in either the CI or the CU group. However, higher pNfL was associated with lower right hippocampal volume and memory score in the CI group. Our results support the utility of pNfL as a biomarker tracking hippocampal atrophy and memory function but not for predicting DMN FC in older adults with cognitive decline of Alzheimer’s type.
Jung et al. (Thu,) studied this question.