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“Neurobiology of Samadhi” refers to the study of what happens in the brain and nervous system during samadhi — the deep meditative absorption described in yogic, Buddhist, and contemplative traditions. Samadhi is often considered the culmination of meditation practice, marked by stillness of mind, heightened awareness, dissolution of the sense of self, and a profound state of unity or absorption.
Here’s a breakdown of its neurobiological aspects:
1. Neural Networks Involved
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Default Mode Network (DMN):
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Normally active during self-referential thought (“me-centered” thinking, daydreaming, ruminating).
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In samadhi, studies show reduced DMN activity, correlating with quieting of the ego and self-boundaries.
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Salience Network & Executive Control Network:
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Meditators show increased connectivity here, suggesting better attention regulation and switching between inner/outer awareness.
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Thalamo-cortical loops:
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Play a role in sensory gating. In deep absorption, filtering of sensory input may explain withdrawal from external stimuli.
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2. Brain Regions
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Prefrontal Cortex: Increased regulation of attention and inhibition of distractions.
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Anterior Cingulate Cortex (ACC): Enhanced monitoring of internal states and conflict resolution.
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Insula: Heightened interoceptive awareness (awareness of breath, body states).
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Posterior Cingulate Cortex (PCC): Often shows deactivation in samadhi, linked to loss of self-focus.
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Parietal Lobes (especially superior parietal lobule): Reduced activity may underlie the loss of spatial boundaries (sense of oneness).
3. Neurochemistry
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Dopamine: Elevated during focused meditation, supporting sustained attention.
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Serotonin & Endorphins: May underlie feelings of bliss, calm, and altered time perception.
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GABA: Increased inhibitory tone → mental quietude and reduced chatter.
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Oxytocin: Linked to feelings of connectedness and compassion in advanced meditation.
4. Brain Waves
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Alpha (8–12 Hz): Associated with relaxed alertness, commonly elevated in meditation.
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Theta (4–7 Hz): Heightened in deep absorption, linked to inward focus and hypnagogic states.
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Gamma (>30 Hz): Experienced meditators show strong, coherent gamma oscillations, possibly reflecting unity of consciousness and heightened integration.
5. Physiological Correlates
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Autonomic Nervous System (ANS):
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Parasympathetic dominance → deep relaxation, lowered heart rate, reduced respiration.
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Yet some samadhi states also show paradoxical heightened arousal with calm awareness.
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Cardiorespiratory Synchrony: Breath slows and aligns with heart rhythms.
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Reduced Metabolic Rate: Oxygen consumption and overall energy expenditure decrease, mimicking deep rest but with heightened awareness.
6. Phenomenological Correlation
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Loss of self-boundaries: Matches reduced DMN and parietal activity.
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Timelessness/Spacelessness: Possibly linked to altered thalamo-cortical dynamics and parietal deactivation.
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Bliss & Unity: Neurochemical shifts (serotonin, endorphins, oxytocin).
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Effortless Awareness: Sustained prefrontal regulation without strain.
✅ In short:
The neurobiology of samadhi points to a unique brain state characterized by quieting of self-referential networks, heightened attention control, altered neurochemistry, coherent oscillations, and parasympathetic dominance. It resembles neither sleep nor ordinary wakefulness but a distinct state of consciousness — deeply restful yet vividly aware.
Would you like me to make a visual diagram (brain regions + networks involved in samadhi) so it’s easier to grasp at a glance?
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