A process for analysing an electroencephalogram (EEG) signal representative of activity of a brain of a subject, including: (i) generating coefficient data for a signal representation of a portion of the EEG signal； (ii) generating, based on the coefficient data, cortical state data representing the brain's receptivity to subcortical input and input from other areas of cortex； (iii) generating cortical input data representing a level of subcortical input to the brain at a time corresponding to the portion of the EEG signal； (iv) generating, based on the cortical state data and the cortical input data, display data representing the functional state of the brain of the subject； and (v) displaying the display data on display means.
