Altered brain morphology and functional connectivity in postmenopausal women: automatic segmentation of whole-brain and thalamic subnuclei and resting-state fMRI

Abstract

The transition to menopause is associated with various physiological changes, including alterations in brain structure and function. However, menopause-related structural and functional changes are poorly understood. The purpose of this study was not only to compare the brain volume changes between premenopausal and postmenopausal women, but also to evaluate the functional connectivity between the targeted brain regions associated with structural atrophy in postmenopausal women. Each 21 premenopausal and postmenopausal women underwent magnetic resonance imaging (MRI). T1-weighted MRI and resting-state functional MRI data were used to compare the brain volume and seed-based functional connectivity, respectively. In statistical analysis, multivariate analysis of variance, with age and whole brain volume as covariates, was used to evaluate surface areas and subcortical volumes between the two groups. Postmenopausal women showed significantly smaller cortical surface, especially in the left medial orbitofrontal cortex (mOFC), right superior temporal cortex, and right lateral orbitofrontal cortex, compared to premenopausal women ( p < 0.05, Bonferroni-corrected) as well as significantly decreased functional connectivity between the left mOFC and the right thalamus was observed ( p < 0.005, Monte-Carlo corrected). Although postmenopausal women did not show volume atrophy in the right thalamus, the volume of the right pulvinar anterior, which is one of the distinguished thalamic subnuclei, was significantly decreased ( p < 0.05, Bonferroni-corrected). Taken together, our findings suggest that diminished brain volume and functional connectivity may be linked to menopause-related symptoms caused by the lower sex hormone levels.

Sex-steroid hormones relate to cerebellar structure and functional connectivity across adulthood

“…Females exhibited less connectivity between lobules I-IV and the cuneus compared to males as they aged, suggesting a potential divergence in neural communication patterns between the sexes with increasing age. This reduced connectivity in females may influence sensory processing and integration, which are key functions of these cortical regions [27,47]. Conversely, females showed greater connectivity between Crus I, Crus II, and the precuneus compared to males as they aged, aligning with previous studies [48].…”

“…As already mentioned, despite the growing body of research, studies examining the effects of sex steroid hormones on cerebellar networks remain limited [25, 26], and conflicting findings persist regarding the potential neuroprotective effects of these hormones on cognitive and brain functions [5, 25, 26]. These hormonal influences suggest that menopause and other periods of hormonal change could significantly affect cerebellar volume, potentially leading to sex-specific aging processes [27].…”