We evaluated different diffusivity measurements of subcortical regions that can be related with different test scores in FAS, SDMT and PASAT test. For this purpose, we evaluated the FA, MD, RD and AD diffusivity maps of U-fibers with the test scores in healthy subjects and RRMS patients. In our sample, FAS test scores are significant linear related with Postcentral gyrus with RD and MD maps in RRMS patients. PASAT test scores are significant linear related with Precentral gyrus with FA and RD maps in healthy subjects. There is no linear relationship between SDMT test score and diffusivity maps.