Morphometric analysis of neuronal and glial cell pathology in the caudate nucleus in late-life depression

Objective: To assess glial and neuronal density and neuronal volume in two areas of the caudate nucleus in late-life major depression. Design: A postmortem study using the disector and nucleator methods to estimate neuronal density and volume and glial density of cells from human brain tissue from the anterior portion (dorsolateral and ventromedial aspects) of the caudate nucleus. Setting: Brain tissues were obtained from the Newcastle Brain Tissue Resource at Newcastle University, UK. Participants: The study group consisted of 13 subjects with late-life major depression and nine comparison subjects of similar age. Results: Evidence of moderate reductions in neuronal density was found in the depressed group in both the dorsolateral and ventromedial areas of the caudate nucleus. There were no significant changes in glial density or neuronal volume in either area nor was there any evidence of differences in depression in early and late-onset subgroups. Conclusions: Neuroimaging abnormalities in frontal and subcortical areas including ischemic hyperintensities and a reduction in volume and metabolism in the caudate nucleus have been reported in late-life depression, and previous morphometric studies have reported neuronal changes in prefrontal cortical areas. The findings in this study extend these morphometric investigations in late-life depression to the caudate nucleus, suggesting that neuronal abnormalities are present in this subcortical nucleus as well as in these related prefrontal areas.