Locus ceruleus morphometry in aging and schizophrenia

Abstract

The locus ceruleus (LC), a pigmented brainstem nucleus rich in noradrenergic neurons, has been proposed to be involved in the pathophysiology of aging and schizophrenia. We undertook a quantitative neuropathological study of the LC in these two conditions. A computing planimeter was employed to count the total number of neurons and measure the volume of the LC, neuronal cross-sectional area, and percent of neuronal area occupied by neuromelanin in the brains of 39 subjects; 13 "normative", 15 leucotomized schizophrenic (most had died in the preneuroleptic era), and 11 leucotomized non-schizophrenic control patients, ranging in age from 11 to 94 years. There was a significant inverse correlation between age and total number of LC neurons, neuronal size, and LC volume, and a significant positive correlation between age and the percentage of neuronal area occupied by neuromelanin. Although schizophrenics did not differ significantly from control groups on any of the parameters of LC morphology, there was a trend for reduced LC volume in schizophrenic brains. Also, the LC of leucotomized patients tended to have increased neuromelanin content and slightly increased cell counts compared to normals, although the importance of this finding is not clear.