Spiral brain dynamics track the temporal unfolding of subjective intensity during the N,N-dimethyltryptamine experience

Psychedelic compounds like N,N-dimethyltryptamine (DMT) cause rapid and substantial shifts in conscious experience, necessitating neuroimaging techniques to monitor the evolution of brain dynamics across space and time. Recent research proposes that rotational (vortex-like) patterns in brain activity may play a role in coordinating widespread neural networks.

In a study employing fMRI data collected under placebo and DMT conditions in a within-subject design, researchers introduced two vorticity-based metrics: spiral vorticity (SV) and spatial spiral vorticity dispersion (SSVD) to gauge the rotational organization and spatial variability of large-scale cortical phase dynamics. The results showed that DMT enhanced SV and SSVD, while simultaneously decreasing temporal irreversibility, suggesting stronger rotational organization, greater spatial variability, and altered directional patterns in cortical activity.

These changes were not consistent across functional systems, with the most significant alterations observed in the default mode, visual, frontoparietal, and dorsal attention networks. The global vorticity measures correlated with the progression of subjective intensity, whereas network-level analyses indicated spatially varied brain-experience coupling.

Additionally, spatiotemporal analyses revealed that the most substantial reorganization of spiral dynamics took place during the offset and recovery phases, rather than at the peak of subjective intensity. These findings demonstrate that spiral dynamics serve as a time-dependent neural marker of the DMT experience, offering a method to connect broad brain dynamics with the evolving subjective experience through the quantification of rotational structure and spatial variability in cortical phase flow.