Response function as a quantitative measure of consciousness in brain dynamics
Physical Review Research December 3, 2025 Wenkang Du, Haiping Huang
A robust, brain-state-dependent neural response function may be a necessary dynamical condition for consciousness. Using intracranial recordings from nonhuman primates across wakefulness, anesthesia, and recovery, researchers fit a nonequilibrium recurrent neural network model to extract the neural response function as an indicator of dynamics complexity. The amplitude of this function peaks near the transition between ordered and chaotic regimes, highlighting criticality as a potential principle for flexible cortical dynamics. During wakefulness, neural responsiveness is strong and widely distributed. Under anesthesia, response amplitudes are suppressed and dynamics become more chaotic. During recovery, the response function is elevated, paralleling the restoration of conscious processing.