The forceps minor white matter modulates cingulo‐opercular functional connectivity change in subjective cognitive decline

Abstract

AbstractBackgroundThe ‘cingulo‐opercular’ network (CON) functional connectivity (FC) decreases in aging and mild cognitive impairment. However, little is known about the cross‐sectional differences or longitudinal changes in CON FC in subjective cognitive decline (SCD). Frontal white‐matter tracts such as the forceps minor exhibit alterations in SCD and, thus, might play a relevant role for CON FC in SCD. Thus, we tested (i) whether baseline SCD predicts CON FC decrease over three years and (ii) whether white matter in the forceps minor modulates that effect.MethodSixty‐nine healthy older participants (13 males; 68.33 ± 7.95 years old) underwent resting‐state functional and diffusion‐weighted magnetic resonance imaging. Forty‐nine of those participants were further enrolled in 2 follow‐ups, about 18 months apart each. The degree of SCD was assessed at baseline with the memory functioning questionnaire (MFQ; greater score indicating more SCD). After imaging data preprocessing, we obtained the average CON FC (correlation between 5 regions) for each time point and the neurite density of the forceps minor (‘structural connectivity’, SC), which was then averaged across time points. A latent growth curve model was fit to the longitudinal FC data, setting the intercept at the last time point. The model tested whether baseline MFQ predicted FC after 3 years (latent intercept) and/or its rate of change (latent slope) and whether the interaction between SC and MFQ predicted the latent intercept of FC.ResultWe did not find evidence of baseline MFQ as a predictor of CON FC after 3 years (b = ‐0.19, 95% confidence interval, CI, [‐0.49, 0.11], p = 0.211) or its rate of change (b = ‐0.17, [‐0.37, 0.03], p = 0.093). However, we found that SC (averaged across all time points) modified the relation between MFQ and FC after 3 years (intercept, b = 0.20, [0.03, 0.37], p = 0.020; FIG).ConclusionGreater SCD predicts lower CON FC after 3 years in individuals with relatively low neurite density in the forceps minor. This evidence implies that CON FC alterations in SCD are dependent upon the forceps minor’s white matter and that these alterations might be associated with attentional or executive‐function changes in SCD.