Low-dose ketamine tilts the cortical excitation–inhibition balance irrespective of systemic physiological response

This randomised, single-blind, placebo-controlled crossover preprint (n=25 healthy adults) found that low-dose ketamine flattened the resting-state EEG aperiodic exponent, an indirect proxy for a shift towards cortical excitation. Ketamine increased heart rate and blood pressure, but heart-rate mediation did not explain the EEG effect. Propofol shifted the exponent in the opposite direction numerically, although its comparison with placebo was not statistically significant (p=.09).