To date there are no in vivo tools for quantifying spatial changes in the microstructure of subcortical gray-matter nuclei. We have developed a quantitative MRI tool, with which we measured variations along the human dorsal striatum, using quantitative T1. We found monotonic gradients along the main axes, consistent with known biological gradients of the striatum. In addition, we found effects of laterality, as well as aging effects. Our method can prove useful for detection and quantification of microstructural irregularities in the striatum in patients suffering from basal ganglia disorders, such as Parkinson’s disease and ADHD.