New World indigenous peoples use psychedelic plants in shamanic and ethnomedical practices far more than in the Old World. Almost all these botanically diverse preparations share tryptamine derivatives, either DMT or related constituents, as active principles. Part 1 of this paper gives an ethnopharmacological overview of major tryptamine-containing New World hallucinogens. Part 2 focuses on ayahuasca and its effects on the human brain. Using SPECT, ayahuasca modulated activity in higher order association areas, increasing blood perfusion mainly in anterior brain regions (frontomedial and anterior cingulate cortices) and medial temporal lobes.
Indigenous peoples of the New World have a long history of using psychedelic plants in shamanic and ethnomedical practices, and such use is much more common there than in the Old World. Although the plants used are botanically diverse, their active compounds are chemically similar, almost all being tryptamine derivatives such as DMT or related substances. Part 1 of this paper gives an ethnopharmacological overview of the major tryptamine-containing hallucinogens found in the New World.