Psilocybin desynchronizes our brains during ego dissolution

From Siegel et al (open source).:

A single dose of psilocybin, a psychedelic that acutely causes distortions of space–time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials^1,2,3,4. In animal models, psilocybin induces neuroplasticity in cortex and hippocampus^5,6,7,8. It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg - a placebo in the form of methylphenidate, (Ritalin)), and brought back for an additional psilocybin dose 6–12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics.

How we got to where we are

In the beginning was the cosmos, fundamentally as incomprehensible to our human brains as quantum chemistry is to a dog’s brain.

What our human brains can understand is that our ultimate emergence from countless generations of less complex organisms can be largely explained by a  simple mechanism that tests the reproductive fitness of varying replicants.

Systems that try to predict the future and dictate whether to go for it or scram - from the chemotaxis of bacteria to the predictive processing of our humans brains - have proved to be more likely to survive and propagate.

Modern neuroscience has proved that our experienced perceptions of sensing and acting are these predictions.  They are fantasies, or illusions, as is our sense of having a self with agency that experiences value, purpose, and meaning. Everything we do and experience is in the service of reducing surprises by fulling these fantasies. An array of neuroendocrine mechanisms have evolved to support this process because it forms the bedrock of human culture and language.

We are as gods, who invent ourselves and our cultures through impersonal emergent processes rising from our biological substrate.

Personal and social dysfunctions can sometimes be addressed by insight into this process, as when interoceptive awareness of the settings of  our autonomic nervous system's axes of arousal, valence, and agency allows us to dial them to more life sustaining values and better regulate our well-being in each instance of the present.

We can distinguish this autonomic substrate from the linguistic cultural overlay it it generates, and allow  the latter to be viewed in a more objective light. This is a deconstruction that permits us to not only let awareness rest closer to the 'engine room' or 'original mind' underlying its transient reactive products, but also to derive from this open awareness the kind of succor or equanimity we once found in the imagined stability of an external world.

Hopefully the deconstruction that takes us into this metaphorical engine room makes us more able to discern and employ illusions that enhance continuation rather than termination of our personal and social evolutionary narratives. 

(The above is MindBlog's 10/25/23 post, repeated here and given a new title.)