A computer-implemented process for measuring brain activity of a subject, including: receiving electroencephalogram (EEG) data representing EEG measurements of electrical brain activity of the subject; and fitting parameters of a neural population model to the EEG data to determine corresponding values of said parameters, including one or more values of an inhibitory postsynaptic potential rate constant (ϒ i ), whereϒ i is representative of states of brain responsiveness, an increase in ϒ i relative to a reference value indicating an enhanced state of brain responsiveness, and a decrease in ϒ i relative to the reference value indicating a decrease in the state of brain responsiveness.
APPARATUS AND PROCESS FOR MEASURING BRAIN ACTIVITY