There is no question that people occasionally have strange experiences, sometimes very strange. There is a tendency to interpret such experiences as external, reflecting something happening in the world, rather than internal, reflecting something happening in our brains.

Neuroscience, however, has provided us a powerful tool for understanding some of these experiences. They are a window into how our brains construct our experience of reality, and what we experience when that process breaks down or is altered by drugs, trauma, electrical stimulation, oxygen deprivation, or other stressors.

A recent study looking at the hallucinogen DMT (N,N-Dimethyltryptamine) adds an interesting insight into our collective knowledge of these altered states of consciousness. The researchers studied 13 healthy volunteers, who were given placebo, and then in a separate session a week later DMT, and extensively questioned about their experiences. The researchers specifically wanted to test the possibility that a DMT-induced hallucination would be similar to reported near-death experiences.

In short they found that the DMT experiences were extremely similar to near-death experiences (NDE), but let’s look at the details.

They gave the subjects an established NDE scale, which assesses for 16 features reported by those who experience an NDE. A score of 7 or higher is considered to be a genuine NDE. All 13 subjects scored 7 or higher on this scale when given DMT. Ten of the 16 features were statistically more likely during DMT than placebo. And the total scores were similar to a historical control group of reported NDEs. So again – DMT produced an experience that was very similar to reported NDEs.

The researchers also evaluated subjects on scales of mystical and paranormal experiences, and on personality type. Unsurprisingly, many subjected reported mystical or paranormal features to their experience. Perhaps more interesting is that there was a strong correlation between being prone to delusional thinking and reporting mystical or paranormal experiences during DMT.

So what does all this mean?

The most fundamental implication of this research, and other similar research, is that fantastical, religious, mystical, and paranormal experiences may be manifestations solely of altered brain activity. Some of the core experiences we are talking about include ego dissolution, which is the fading away of the self, or any distinction between the self and the rest of the universe. People experience this as a profound oneness with other things, other people, or just the universe itself.

Another core component is the out-of-body experience – a feeling of separation from the body. People may feel as if they are floating, and also often report seeing their own body as if they are separated from it.

Yet another core experience is being in the presence of another entity or intelligence. Often it is perceived that this intelligence is profound – hyperintelligent – and yet inhuman or distant in some way. Early researchers of DMT reported encountering “mechanical elves” in the “hyperspace” of DMT. Sometimes the entities are perceived as physically small.

Visual illusions and hallucinations are also common. With DMT there is usually dramatic hallucinations of light, color, and shapes which may be abstract or solid.

Another common element is time-dilation. The subjective experience of time is altered profoundly, and a short period of time can seem much longer. This could have implications in interpreted the memories of those who experienced NDEs.

Each of these experiences reflect something basic about brain function. We can be made to feel we are separated from the self or joined with the universe because the feeling that we are a distinct self is an active constructive process of the brain that can be disrupted. Likewise we can be made to feel as if we are separated from our body because the sensation we are in our body is actively constructed. There are circuits in the brain that produce this subjective experience, and their functioning can be altered or interrupted.

Experiences with DMT and other hallucinogens also implies that there is circuitry in the brain related to experiences other minds – that there are other intelligences and agents out there in the world. Psychologists refer to this as a “theory of mind” – the understanding that other people have thoughts, feeling, and motivations just like we do. Perhaps the experience of an intelligent entity results from this circuitry, while reality-testing circuitry is inhibited, or simply in the context of ego-dissolution.

There is a lot to unpack here, but this is telling us something about how the brain functions and creates the most fundamental aspect of our experience of reality.

Further, that DMT can induce such experiences means that there are receptors in the brain that produce these experiences when activated (or blocked). This further implies there are endogenous neurotransmitters in the brain that can produce them. Why?

That is an interesting question that will require further research. It’s possible that DMT is powerfully activating receptors that are involved with dreaming (or at least were at some point in our recent evolutionary history). Also, mild feelings of euphoria, well-being, or connectedness to other people or the community are ordinary experiences produced in part by these circuits. When powerfully activated by a drug they may push these normal experiences to extremes.

Another way to understand the experiences under the influence of DMT is not so much that it is hyperactivating a more mundane neurological phenomenon, but disinhibiting it by inhibiting other circuits. The brain is like bloatware – there are lots of circuits in the brain functioning all the time and slowing down the whole process, but providing functionality. If you inhibit some circuits you remove their functions, but other circuits are now free to function more robustly. Take away all that processing-intensive reality testing, and other circuits may function out of control.

We are dealing with some of the most complex functions of the brain, and it will take much more study to tease it all apart. The researchers did also study the subjects with EEG and say that they will reports those findings separately. Perhaps that will give us more insight into what’s happening in the brain under the influence of DMT.

The meta-lesson of all this is that we are our brains. When you alter brain function, you alter our minds, even at their most fundamental level of functioning. Mind function is not just changed in random and unpredictable ways, or made fuzzy. Drugs like DMT will change brain function is specific and fairly predictable ways that track with specific circuits and functions in the brain. The brain really is just a very complex machine, and we can turn dials and knobs to change how it functions (even though we still have a lot to learn about what all the knobs are and how they function).

I understand why people who have such experiences would interpret them as saying something about the world, rather than something about their brain. Consciousness seems to function specifically in such a way as to produce that illusion. We can now pierce that illusion, however, with neuroscience, and understand the functioning of our own brains.