Network neuroscience (Cambridge, Mass.)
January 1, 2025
Isaac N Treves, Winson F Z Yang, Terje Sparby et al.
6 citations
Advanced meditation involves states and stages that develop with experience. A case study using 7-T fMRI and dynamic functional connectivity analysis of a meditator practicing jhāna advanced absorptive concentration meditation (ACAM-J) identified three distinct brain states: a default-mode network (DMN)-anticorrelated state, a hyperconnected state, and a sparsely connected state. The DMN-anticorrelated state was more prevalent during ACAM-J than control conditions and increased with deeper meditation. The hyperconnected state, marked by elevated thalamocortical and somatomotor connectivity, was also more common during ACAM-J but decreased over the session, corresponding to reports of wider attention and reduced physical sensations. This suggests that functional neuroimaging can track the dynamics of altered states of consciousness in advanced meditators.
Network neuroscience (Cambridge, Mass.)
January 1, 2024
Paulina Clara Dagnino, Javier A Galadí, Estela Càmara et al.
4 citations
Meditation produces distinct whole-brain dynamics compared to rest. Using fMRI data from expert meditators and controls, the authors defined probabilistic metastable substates (PMS) for each condition, capturing different probabilities of dynamic brain patterns. They then fit a whole-brain model to these substates and performed in silico perturbations to simulate transitions between resting-state and meditation. The results show that localized artificial perturbations can induce such transitions, and the sensitivity of different brain areas to perturbation varies. This mechanistic framework clarifies how meditation alters brain dynamics and suggests potential applications for health and therapy.
Network neuroscience (Cambridge, Mass.)
January 1, 2026
Hiba Sheheitli, Robert Hermosillo, Gracie Grimsrud et al.
Metastability of BOLD fMRI signals, a proxy for brain dynamics, shows within-subject reliability comparable to static functional connectivity when enough data are used, but the amount needed varies across brain networks. Combining network-specific metastability metrics into a single feature vector improves reliability by an order of magnitude. This finding was reproduced in the Midnight Scan Club dataset (10 subjects over 10 days). The measure also proved sensitive to change in brain dynamics under psilocybin. The authors conclude the combined feature vector is a promising candidate for individual-specific biomarkers and precision neuromodulation targets.
Network neuroscience (Cambridge, Mass.)
January 1, 2025
Ioanna A Amaya, Till Nierhaus, Timo T Schmidt
Rhythmic flicker light stimulation at 10 Hz reliably induces transient visual hallucinations in healthy people, while arrhythmic flicker does so less. Using fMRI, rhythmic flicker produced stronger activation in higher order visual cortices and selectively increased connectivity between ventroanterior thalamic nuclei and those cortices, compared to arrhythmic control. The strength of this connectivity correlated positively with the subjective intensity of hallucinations. Because the ventroanterior thalamus and higher order visual areas do not receive primary visual inputs, the findings suggest the thalamus coordinates cortical activity to generate hallucinatory experiences, offering insight into pathological hallucinations.