Susceptibility and Volume Measures of the Mammillary Bodies Between Mild Cognitively Impaired Patients and Healthy Controls

Abstract

Purpose: To investigate the baseline values and differences for susceptibility and volume of the mammillary bodies between mild cognitively impaired (MCI) patients and healthy controls (HCs), and further explore their differences in relation to gender, MCI subtypes and apolipoprotein E (APOE) genotypes. Methods: T1-weighted and multi-echo gradient echo imaging sequences were acquired on a 3T MR scanner to evaluate the T1W based volume and susceptibility differences in the mammillary body for 47 MCI and 47 HCs. T-tests were performed to compare volume and susceptibility between groups, and right and left hemispheres. Correlation analysis was used to relate the volume and mean susceptibility as a function of age in MCI and HC groups separately, and to investigate the relationship of susceptibility with the neuro-psychological scales in the MCI group. Results: Susceptibility was found to be elevated within the right mammillary body in MCI patients compared to HCs (p < 0.05). There were no differences for the mammillary body volumes between the MCI and HC groups, although there was a reduction in volume with age for the MCI group (p = 0.007). Women showed decreased mammillary body volume compared to men in the HC group (p = 0.004). No significant differences were found in relation to MCI subtypes and APOE genotypes. No significant correlations were observed between mammillary body susceptibility with neuro-psychological scales. Conclusion: This work provides a quantitative baseline for both the volume and susceptibility of the mammillary body which can be used for future studies of cognitive impairment patients underlying the pathology of the Papez circuit.

Hypothalamic integrity is associated with age, sex and cognitive function across lifespan: A comparative analysis of two large population-based cohort studies

“…45 Moreover, this region harbors the supramammillary nucleus, which could modulate memory function through its extensive connections to the hippocampus. 2 We also found a strong relationship between MMB volume and total memory, as well as episodic verbal memory, which extends findings form previous (animal) studies, 19,20 ,46 and highlights the role of the fornix-mammillary body circuit in regulating episodic memory function. 47 Notably, MMB volume was also related to processing speed in both datasets, which is in line with a recent clinical case-control study in children.…”

Normative mammillary body volumes: From the neonatal period to young adult

“…Both post-mortem and MRI studies have previously reported larger MBs in males than females ( Bernstein et al, 2012 ; Jin et al, 2020 ; Sheedy et al, 1999 ); however, these studies did not correct for overall brain volume. In contrast, Raz et al did control for skull size and found no sex-related differences ( Raz et al, 1992 ).…”

“…To better understand the contribution of MB neuropathology in these diverse conditions, it is necessary to have a detailed structural knowledge of the MBs in normal populations. While normative data for the MBs has been reported for adults ( Raz et al, 1992 ), and older adults in particular ( Jin et al, 2020 ), the equivalent data for younger populations has not previously been available.…”

“…Very few previous studies have assessed lateralization in the MBs. Jin et al found no hemispheric differences in the MBs of older individuals with or without mild cognitive impairment ( Jin et al, 2020 ). However, there were only 47 individuals in each subgroup so it is possible that, given the hemispheric differences we observed were quite small, larger datasets are required for hemispheric differences to emerge.…”

Going round in circles—The Papez circuit in Alzheimer's disease

“…For instance, MB volumetric loss in mild to moderate AD has been described when compared with healthy controls (Callen et al, 2001), MCI and older people with a subjective cognitive decline (Copenhaver et al, 2006). Increased iron level in the right mammillary body with no apparent volumetric differences has been reported when comparing MCI and healthy controls (Jin et al, 2020). Substantial decrease in neuronal population and abbreviation in dendritic arbores have also been reported in early cases of AD using electron microscopy and silver impregnation techniques (Baloyannis et al, 2016).…”