1. A method for assessing brain state comprising: analysing mammalian brain electroencephalogram (EEG) recordings using an eighth order autoregressive and fifth order moving average discrete time equation; obtaining a z-domain equation by taking a z-transform for said eighth order autoregressive and fifth order moving average discrete time equation; determining, using a processing unit, poles and zeroes in the solution of the z-domain equation; and plotting the poles onto the complex plane; and displaying positions of the poles.