Distributed harmonic patterns of structure-function dependence orchestrate human consciousness

This theory-building paper (2023) shows that structure-function coupling (patterns of brain activity) is a generalisable indicator of consciousness. An increase in functional coupling indicates a loss of consciousness (e.g. brain-inured patients or anaesthesia), and opposite changes (decoupling of brain function from structure) are seen under the influence of psychedelics (e.g. LSD or ketamine).

Abstract

“A central question in neuroscience is how consciousness arises from the dynamic interplay of brain structure and function. Here we decompose functional MRI signals from pathological and pharmacologically-induced perturbations of consciousness into distributed patterns of structure-function dependence across scales: the harmonic modes of the human structural connectome. We show that structure-function coupling is a generalisable indicator of consciousness that is under bi-directional neuromodulatory control. We find increased structure-function coupling across scales during loss of consciousness, whether due to anaesthesia or brain injury, capable of discriminating between behaviourally indistinguishable sub-categories of brain-injured patients, tracking the presence of covert consciousness. The opposite harmonic signature characterises the altered state induced by LSD or ketamine, reflecting psychedelic-induced decoupling of brain function from structure and correlating with physiological and subjective scores. Overall, connectome harmonic decomposition reveals how neuromodulation and the network architecture of the human connectome jointly shape consciousness and distributed functional activation across scales.”

Authors: Andrea I. Luppi, Jakub Vohryzek, Morten L. Kringelbach, Pedro A. M. Mediano, Michael M. Craig, Ram Adapa, Robin L. Carhart-Harris, Leor Roseman, Ioannis Pappas, Alexander R. D. Peattie, Anne E. Manktelow, Barbara J. Sahakian, Paola Finoia, Guy B. Williams, Judith Allanson, John D. Pickard, David K. Menon, Selen Atasoy & Emmanuel A. Stamatakis

Summary of Distributed harmonic patterns of structure-function dependence orchestrate human consciousness

Understanding the neural underpinnings of human consciousness is a major challenge of contemporary neuroscience. Recent advances have provided fundamental insights into loss of consciousness and its signatures, including the pattern of co-fluctuations between regional BOLD time series (functional connectivity; FC) and anatomical connections between regions.

Existing investigations of structure-function correspondence during altered states of consciousness have typically relied on correlation or distance metrics, which do not account for the inherently asymmetric relationship between brain structure and function.