It turns out that DMT is widely present in the mammalian brain. In 2019, researchers at the University of Michigan not only found the compound in various locations in rat brains, but they also discovered neurons with the two enzymes required to make it. Moreover, the neurons seem to produce DMT at levels comparable to those of other key neurotransmitters like dopamine, which drives pleasure, and serotonin, which stabilizes mood.
DMT has also been found in small amounts in human brain tissue and larger amounts in cerebrospinal fluid, a clear fluid that surrounds the brain and spinal cord. Is it possible that DMT floods the human brain at death, causing vivid dreams and NDEs?
The University of Michigan researchers witnessed this happen in rats. They directly measured brain levels of DMT as rats suffered cardiac arrest and saw the substance spike up to ten times above baseline levels, enough to trigger psychedelic effects. If a similar increase also occurs in humans, it might just account for NDEs and vivid dreaming near death. But a larger dose might be necessary in alert, healthy subjects.