What happens when the self dissolves?

Before exploring altered states, it helps to understand the Default Mode Network (DMN) — a set of interconnected brain regions (medial prefrontal cortex, posterior cingulate cortex, angular gyrus, and others) that are most active when the brain is at rest.

The DMN is associated with:

• Self-referential thinking: thoughts about yourself, your identity, your narrative
• Mind wandering: daydreaming, rumination, mental time travel
• Autobiographical memory: recalling your past and imagining your future
• Theory of mind: modeling what other people think and feel

The DMN is, in a sense, the neural basis of the self — the internal narrator that weaves your experience into a continuous story. And it turns out to be a key target of many altered states.

01

What Happens in the Brain

Classical psychedelics — psilocybin (mushrooms), LSD, DMT (ayahuasca), mescaline — work primarily by activating serotonin 5-HT2A receptors. Their effects on consciousness are profound:

• DMN disruption: psychedelics consistently reduce functional connectivity within the Default Mode Network. The self-network quiets down.
• Increased global connectivity: brain regions that don't normally communicate start talking to each other. The brain becomes more interconnected, less modular.
• Ego dissolution: the subjective experience of the boundary between self and world dissolving. Users report losing the sense of being a separate "I."

A 2023 systematic review found consistent evidence that psychedelics reduce within-DMN connectivity and increase connectivity between the DMN and other networks — and that this reconfiguration correlates with both the intensity of subjective experience and therapeutic outcomes.

02

What This Tells Us About Consciousness

Psychedelics reveal that the sense of self — the feeling of being a unified "I" with a continuous narrative — is not a fixed feature of consciousness. It's a construct, generated by specific brain networks, that can be temporarily dissolved.

Consciousness persists during ego dissolution. People still experience. But they experience without the usual frame of self-reference. This suggests that selfhood and consciousness, while usually intertwined, are separable.

It also suggests that the "everyday" sense of self may function more like a filter — constraining consciousness to a manageable, survival-relevant subset of possible experience. Psychedelics loosen that filter.

03

Attention, Awareness, and the Disappearing Self

Long-term meditation practice produces changes in consciousness that overlap remarkably with psychedelic states — but arrived at through training rather than pharmacology:

• Reduced DMN activity: experienced meditators show decreased activity in the Default Mode Network, particularly during meditation but also at rest
• Decreased mind wandering: the inner narrator quiets
• Increased metacognitive awareness: meditators report a growing ability to observe thoughts without being caught up in them
• Non-dual awareness: advanced practitioners describe states where the sense of a separate observer dissolves, leaving "awareness without a self"

04

The Convergence

That psychedelics and meditation produce overlapping effects through completely different mechanisms — one pharmacological, one attentional — is significant. Both reduce DMN dominance. Both can produce ego dissolution. Both report experiences of consciousness without a stable self.

This convergence suggests the default self is a process, not a thing — something the brain actively constructs, and which can be deconstructed.

05

The Nightly Dissolution

Every night, consciousness undergoes a radical transformation that we mostly ignore:

• NREM deep sleep: consciousness appears to vanish. Brain activity becomes slow, synchronized, and highly integrated. IIT researchers have noted that the brain's Φ may actually remain high during deep sleep, raising questions about whether consciousness truly disappears or merely becomes unreportable.
• REM sleep (dreaming): consciousness returns, but in a bizarre form. Prefrontal cortex activity drops (reducing critical thinking and self-monitoring), while visual and emotional areas become highly active. The result: vivid, immersive experiences with no insight that they're not real.
• Lucid dreaming: a hybrid state where the dreamer becomes aware they are dreaming. Prefrontal cortex activity increases compared to normal REM — and with it, metacognition, self-awareness, and the ability to exercise "will" within the dream.

06

What Dreams Tell Us

Dreams show that consciousness doesn't require external input. The brain generates a complete phenomenal world from its own activity. They also show that self-awareness and consciousness can come apart: in a normal dream you are conscious but not self-aware; in a lucid dream, self-awareness returns.

This dissociation is important for theories of consciousness. GWT struggles to explain dreams (what is being "globally broadcast" to whom?). IIT handles them more naturally (the brain's integrated information structure generates experience regardless of external input).

07

Turning Consciousness Off

General anesthesia is the closest thing we have to a controlled experiment in consciousness elimination. Anesthetics don't just eliminate pain (that's local anesthesia) — they eliminate experience itself.

Key findings:

• Different anesthetic drugs (propofol, sevoflurane, ketamine) act on different receptors, but they share a common effect: disrupting long-range cortical connectivity
• Under anesthesia, local brain regions still process information, but the global integration that characterizes consciousness breaks down
• This is consistent with both IIT (reduced integration = reduced Φ) and GWT (no global broadcast = no consciousness)
• The transition is not gradual — it's more like a phase transition, a sudden shift from one state to another

Anesthesia provides perhaps the strongest evidence that consciousness depends on integration — the brain's ability to combine information across regions into a unified whole.