The research that Strassman describes, conducted at the hospital of the University of New Mexico between 1990 and 1995, includes a dose-response study, a tolerance study, and mechanism-of-action studies to determine which brain receptors mediate DMT’s effects. Sixty volunteers participated. There was no development of tolerance. Findings were inconclusive as to which serotonin receptor regulates DMT’s effects. Throughout the studies, Strassman monitored the effects of the drug on heart rate, pulse, hormone levels, and body temperature. For some subjects, he used an EEG or magnetic resonance imaging head scan to measure which brain sites were most active during a DMT experience. Throughout his report, he is sensitive to issues of set and setting; his orientation as a clinician is evident in the way he counsels volunteers through their psychedelic sessions and in his thoughtful follow-up with them.