Long-term meditation practitioners show greater functional connectivity within the default mode network, specifically in the medial prefrontal cortex, compared to non-meditators, even when not actively meditating. This suggests that regular meditation practice may produce lasting changes in brain regions involved in internalized attention and self-referential thought.
People with schizophrenia experience significant disturbances in the minimal self, particularly in the sense of body ownership and sense of agency. A meta-analysis of 25 studies (690 patients, 979 controls) found a moderate overall effect (Hedge's g = 0.51) indicating basic self-disturbance. Body ownership showed a large effect (0.91), agency a moderate effect (0.49), and self-reported subjective experiences a moderate effect (0.57). The disturbed sense of agency suggests exaggerated self-consciousness rather than a diminished sense of self. Results remained significant after correcting for publication bias.
Psilocybin, a hallucinogen that mimics psychotic symptoms, alters brain connectivity in ways similar to psychosis. In a double-blind placebo-controlled trial with 20 healthy subjects, standard coherence analysis showed decreased connectivity in theta, alpha, and beta brainwave bands, particularly in frontotemporal and frontoparietal regions, along with frontal interhemispheric disconnection. Changes in higher frequencies were less significant and often opposite. In contrast, eLORETA connectivity analysis found no changes in lower frequencies but increased connectivity in high gamma (50-100 Hz). These preliminary results suggest psilocybin-induced connectivity changes align with those seen in psychotic patients.
A 4-day intensive meditation retreat improved executive attention and increased neural activity in brain regions supporting attention networks. In a randomized trial, 23 meditators and 14 relaxation retreat participants performed the attention network test during fMRI before and after the intervention. The meditation group showed significantly better behavioral performance on executive control and increased activation in the anterior cingulate cortex and dorsolateral prefrontal cortex. Activity in the right ACC predicted individual behavioral conflict levels. Alerting and orienting networks also showed enhanced activity after meditation. The findings suggest short-term meditation can strengthen attention networks at the neural level and may benefit those at risk of cognitive deficits.