Age-related regional differences in cerebellar vermis observed in vivo
N. Raz, I. J. Torres, W. D. Spencer, K. White and J. D. Acker
Department of Psychology, Memphis State University, TN 38152.
We investigated age-related differences in the cerebellar vermis. The areas
of five vermal regions of interest were estimated from digitized
midsagittal magnetic resonance imaging scans of 29 healthy volunteers and
30 neurologically intact patients (aged 18 to 78 years) who were free of
vestibular symptoms, seizures, psychosis, or alcoholism. The five regions
of interest included the following: (1) lingula and centralis, (2) culmen,
(3) declive, folium, and tuber, (4) pyramis, and (5) uvula and nodulus. The
ventral pons was used as a control region. After covarying skull size, we
found a significant age-related reduction in the total area of the
cerebellar vermis. The area of the dorsal regions declined with age,
whereas the ventral segments of the vermis--lingula-centralis and
uvula-nodulus--showed no significant age-related shrinkage. Notably, the
area of the most dorsomedial portion, the declive-folium-tuber, tended to
be more strongly associated with age than other segments. The pontine area
was unaffected by age. No sex differences were found in the area of the
vermis or its subdivisions, but the ventral pontine area was larger in male
subjects than in female subjects, even after adjustment for skull size. The
mechanisms underlying the observed differences are unclear. It appears,
however, that phylogenetically more recent vermal regions, which are late
to mature and are endowed with more extensive cortical connections, are the
most vulnerable to the effects of aging.
