Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
331388 | Neurobiology of Aging | 2007 | 7 Pages |
We previously reported that high circulating free testosterone (T) was associated with better performance on tests of memory, executive function, and spatial ability, and with a reduced risk for Alzheimer's disease. In this study, we report that free T levels, measured on multiple occasions over 14 years, predict regional cerebral blood flow (rCBF) measured by PET in 40 older men. Voxel-based regression, indicated that higher Free T was associated with increased rCBF in the hippocampus bilaterally (extending to the parahippocampal gyrus on the right), anterior cingulate gyrus, and right inferior frontal cortex. Total T concentrations were positively correlated with rCBF in the left putamen, bilateral thalamus, and left inferior frontal cortex and negatively correlated with amygdala rCBF bilaterally. These findings suggest that endogenous T influences brain physiology in regions critical for memory and attention and provide one mechanism through which T may affect cognitive function.