1. LSD alters dynamic integration and segregation in the human brain
- Author
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Leor Roseman, Robin L. Carhart-Harris, Andrea I. Luppi, David K. Menon, Ioannis Pappas, Emmanuel Stamatakis, Luppi, Andrea [0000-0002-3461-6431], Menon, David [0000-0002-3228-9692], Stamatakis, Emmanuel [0000-0001-6955-9601], and Apollo - University of Cambridge Repository
- Subjects
Male ,Global integration ,Cognitive Neuroscience ,FMRI dynamics ,Integration-segregation ,050105 experimental psychology ,Article ,lcsh:RC321-571 ,LSD ,03 medical and health sciences ,0302 clinical medicine ,Neural Pathways ,medicine ,Image Processing, Computer-Assisted ,Humans ,0501 psychology and cognitive sciences ,Prefrontal cortex ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Brain function ,Dynamic functional connectivity ,Brain Mapping ,Small-world network ,Structure-function ,Functional connectivity ,05 social sciences ,Brain ,Human brain ,Complexity ,Magnetic Resonance Imaging ,Lysergic Acid Diethylamide ,medicine.anatomical_structure ,Neurology ,Hallucinogens ,Female ,Nerve Net ,Psychology ,Neuroscience ,030217 neurology & neurosurgery ,Stream of consciousness (psychology) - Abstract
Highlights • LSD untethers functional connectivity from the constraint of structural connectivity. • Increased small-worldness of brain networks predicts LSD-induced ego-dissolution. • LSD has time-specific effects on brain network integration and segregation. • LSD increases the complexity of segregated brain states. • Results bridge pharmacodynamics, subjective experience and brain dynamics., Investigating changes in brain function induced by mind-altering substances such as LSD is a powerful method for interrogating and understanding how mind interfaces with brain, by connecting novel psychological phenomena with their neurobiological correlates. LSD is known to increase measures of brain complexity, potentially reflecting a neurobiological correlate of the especially rich phenomenological content of psychedelic-induced experiences. Yet although the subjective stream of consciousness is a constant ebb and flow, no studies to date have investigated how LSD influences the dynamics of functional connectivity in the human brain. Focusing on the two fundamental network properties of integration and segregation, here we combined graph theory and dynamic functional connectivity from resting-state functional MRI to examine time-resolved effects of LSD on brain networks properties and subjective experiences. Our main finding is that the effects of LSD on brain function and subjective experience are non-uniform in time: LSD makes globally segregated sub-states of dynamic functional connectivity more complex, and weakens the relationship between functional and anatomical connectivity. On a regional level, LSD reduces functional connectivity of the anterior medial prefrontal cortex, specifically during states of high segregation. Time-specific effects were correlated with different aspects of subjective experiences; in particular, ego dissolution was predicted by increased small-world organisation during a state of high global integration. These results reveal a more nuanced, temporally-specific picture of altered brain connectivity and complexity under psychedelics than has previously been reported.
- Published
- 2021