Abstract
Much evidence seems to suggest the cortex operates near a critical point, yet a single set of exponents defining its universality class has not been found. In fact, when critical exponents are estimated from data, they widely differ across species, individuals of the same species, and even over time, or depending on stimulus. Interestingly, these exponents still approximately hold to a dynamical scaling relation. Here we show that the theory of quasicriticality, an organizing principle for brain dynamics, can account for this paradoxical situation. As external stimuli drive the cortex, quasicriticality predicts a departure from criticality along a Widom line with exponents that decrease in absolute value, while still holding approximately to a dynamical scaling relation. We use simulations and experimental data to confirm these predictions and describe new ones that could be tested soon.
- Received 1 September 2020
- Revised 20 November 2020
- Accepted 23 December 2020
DOI:https://doi.org/10.1103/PhysRevLett.126.098101
© 2021 American Physical Society
Physics Subject Headings (PhySH)
Viewpoint
The Brain—as Critical as Possible
Published 1 March 2021
A constant bombardment of stimuli drives the brain’s dynamics away from a critical point to a “quasicritical” state.
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