Advanced concentrative absorption meditation produces distinct, distributed brain-wide activity patterns that differ from ordinary consciousness, as shown by ultrahigh-field 7T fMRI in a single expert meditator. Using geometric eigenmode decomposition, the study found elevated global brain state power and energy during meditation compared to control tasks, with mid-frequency brain state power and energy following a non-random, cubic trajectory across the meditation sequence. These brain state differences correlated with subjective reports of attention, meditation quality, and sensations. The findings reveal similarities and differences between advanced meditation and psychedelic-induced states, offering insights into refined conscious states and their implications for well-being.
Visual hallucinations in Lewy body diseases (Parkinson's disease and dementia with Lewy bodies) and those induced by serotonergic psychedelics (psilocybin, mescaline) share overlapping phenomenology and neural mechanisms, despite different underlying causes. Both conditions produce visual aberrations from minor distortions to complex hallucinations, including illusory motion and entity encounters. Neuroimaging shows a common pattern of overactive associative cortex and underactive sensory cortex. Serotonin 2A receptor modulation is involved in both: psychedelics act through 5-HT2A and 5-HT1A receptors, while in Lewy body diseases, 5-HT2A receptor upregulation correlates with increased hallucinations, and blocking it with pimavanserin reduces them. Shared cortical signatures include reduced visual evoked responses and shifts toward visual excitation.