Non-human primates are used by the university to research the effects of drug addiction. The studies are led by Marilyn Carroll, a professor of psychiatry and neuroscience. As of October 2000, Carroll's laboratory was using 34 rhesus monkeys in these studies, according to a meeting of the university's Social Concerns Committee, a figure confirmed in a May 15, 2006 census obtained by the Minnesota Primate Freedom Project, a chapter of the national Primate Freedom Project. Carroll has received $8,888,593 in grants for her work from the National Institutes of Health (NIH) since 1996.