Effective Connectivity of Functionally Anticorrelated Networks Under Lysergic Acid Diethylamide.
Biological psychiatry – February 01, 2023
Source: PubMed
Summary
LSD's profound ability to alter self-perception stems from its unique impact on brain network communication. Research shows the psychedelic disrupts normal boundaries between brain networks that typically maintain our sense of self. Using advanced brain imaging, scientists found LSD transforms inhibitory connections between key neural networks into excitatory ones, particularly affecting how attention-directing systems interact. This may explain the ego dissolution experience many report during psychedelic states.
Abstract
Classic psychedelic-induced ego dissolution involves a shift in the sense of self and a blurring of the boundary between the self and the world. A similar phenomenon is identified in psychopathology and is associated with the balance of anticorrelated activity between the default mode network, which directs attention inward, and the salience network, which recruits the dorsal attention network to direct attention outward. To test whether changes in anticorrelated networks underlie the peak effects of lysergic acid diethylamide (LSD), we applied dynamic causal modeling to infer effective connectivity of resting-state functional magnetic resonance imaging scans from a study of 25 healthy adults who were administered 100 μg of LSD or placebo. We found that inhibitory effective connectivity from the salience network to the default mode network became excitatory, and inhibitory effective connectivity from the default mode network to the dorsal attention network decreased under the peak effect of LSD. The effective connectivity changes we identified may reflect diminution of the functional anticorrelation between resting-state networks that may be a key neural mechanism of LSD and underlie ego dissolution. Our findings suggest that changes to the sense of self and subject-object boundaries across different states of consciousness may depend upon the organized balance of effective connectivity of resting-state networks.