Fig. 2.

CBV measured from the dentate gyrus differentially correlates with age in rhesus monkeys. (A) Individual examples of gadolinium-induced change in MRI signal, a measure of CBV and a correlate of brain metabolism, acquired from a young and old rhesus monkey. Warmer colors indicate higher CBV. The white circle, identified in precontrast images, overlies the dentate gyrus. (B) CBV measurements are plotted against age for individual hippocampal subregions. A significant age-related decline in CBV was observed only the dentate gyrus. (C) CBV measurements are plotted against memory performance on the delayed nonmatching-to-sample test. A significant relationship between CBV and memory was observed only in the dentate gyrus.