Gonna comment from the point of view of computational neuroscience, as it’s where I come from. Human brains and senses perform a sort of compressed sensing, and I use the term here in a more general sense than the specific technical one from signal prodessing theory, but the core idea is that your perception constructs a mental model of a world that is much more continuous and in some respects detailed than the sparseness of the raw information stream coming from your senses. The brain does this because it doesn’t purely rely on this sensory data but combines it with a very large amount of priors that are part genetic and part developmentally acquired. It continuously answers he question, what is the most likely image of the world around me given my sensory input and my encoded priors about what the world is like.
DMT messes with both parts of this. It adds extra detail to the sensory side of things. At low doses this makes things seem like they are in higher resolution, sharper with more vibrant colors etc. which fools some people into thinking that DMT is showing them a more real version of the world. At higher doses the extra details increase so much that they are no longer embeddable into Euclidean space and the really crazy visuals that other psychedelics cannot give begin. See the video for more on this. But beyond this effect, DMT also warps the priors about the world in your brain and also how they are integrated with the sensory information in order to generate a model of the world. See the two papers for more on this.
https://m.youtube.com/watch?v=loCBvaj4eSghttps://www.pnas.org/doi/10.1073/pnas.2218949120https://www.researchgate.net/publication/277281153_ESSAY_Building_Alien_Worlds-_The_Neuropsychological_and_Evolutionary_Implications_of_the_Astonishing_Psychoactive_Effects_of_NN-Dimethyltryptamine_DMT 