It has long been suspected that living systems operate out of thermodynamic equilibrium  , consuming energy and producing entropy in the environment in order to perform biological functions. Recent efforts at the microscale have established that non-equilibrium processes are critical for molecular and cellular operations . However, it remains unclear whether non-equilibrium dynamics manifest at macroscopic scales, and if so, how such dynamics support higher-order biological functions. Here we present a framework to probe for non-equilibrium processes by quantifying entropy production in macroscopic systems. We apply our method to the human brain, URLan whose immense metabolic consumption drives a diverse range of cognitive functions. Using whole-brain imaging data, we demonstrate that the brain fundamentally operates out of equilibrium at large scales. Moreover, we find that the brain produces more entropy -- operating further from equilibrium -- when performing physically and cognitively demanding tasks. To understand how the brain operates at different distances from equilibrium, we use simulations to show that the non-equilibrium nature of macroscopic systems is modulated by the strength of interactions at the microscale. Together, these results suggest that non-equilibrium dynamics are vital for cognition, and provide a general tool for quantifying the non-equilibrium nature of macroscopic systems.
Living systems operate out of thermodynamic equilibrium at small scales , consuming energy and producing entropy in the environment in order to perform molecular and cellular functions . However, it remains unclear whether non-equilibrium dynamics manifest at macroscopic scales, and if so, how such dynamics support higher-order biological functions. Here we present a framework to probe for non-equilibrium dynamics by quantifying entropy production in macroscopic systems. We apply our method to the human brain, URLan whose immense metabolic consumption drives a diverse range of cognitive functions. Using whole-brain imaging data, we demonstrate that the brain fundamentally operates out of equilibrium at large scales. Moreover, we find that the brain produces more entropy -- operating further from equilibrium -- when performing physically and cognitively demanding tasks. By simulating an Ising model, we show that macroscopic non-equilibrium dynamics can arise from asymmetries in the interactions at the microscale. Together, these results suggest that non-equilibrium dynamics are vital for cognition, and provide a general tool for quantifying the non-equilibrium nature of macroscopic systems.
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It has long been suspected that living
Living
A
at small scales
D
biological functions. Recent efforts at the microscale have established that non-equilibrium processes are critical for
R
operations
functions
R
processes
dynamics
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To understand how the brain operates at different distances from equilibrium, we use simulations to show that the
By simulating an Ising model, we show that macroscopic
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nature of macroscopic systems is modulated by the strength of
dynamics can arise from asymmetries in the