Age-related shrinkage of the mamillary bodies: in vivo MRI evidence.

Mamillary body (MB) is a diencephalic structure hypothesized to be involved in memory, a cognitive function that declines with age. In this study, age-related differences in the size of MB were examined in vivo using magnetic resonance (MR) imaging. The cross-sectional area of the MB was estimated from MR images of the brain in healthy volunteers and neurologically intact patients (age 18-78). The cross-sectional area of the tectum was used as a control region of interest. We found a significant age-related reduction in the area of the MB, but not of the tectum. No sex differences were observed in the size of either structure.