Abstract Biological background to understand the brain system and the electrical activity has been discussed. A linear model of global electro cortical activity developed by wright and kydd is described. The model proposed that the properties of the electrocortical waves be clearly distinguished from the microscopic and nonlinear interactions which underlie them. This model is generalized to include magnetic fields Covariant model of global electro cortical activity is developed by considering telencephalonic structures as mass of linked oscillators generating activity with a number of resonant modes. Equations for the signals are written in the commoving frame and then transformed into the laboratory frame. The state transition matrix is obtained in the presence of electric and magnetic fields. Generalized coupling dependent on both the electrical potentials and their rate of change is introduced in covariant model of global electro cortical activity. First order shift in frequencies is obtained. A condition of impedance matching relates the coupling parameters and damping coefficients Effects of perturbing fields are described. Effects of weak magnetic fields are considered on a covariant model of global electro cortical activity. A method to calculate the ratio of components of signal velocities is given. Effects of weightlessness and acceleration are described. Weightlessness has very small effects on electroencephalograms (EEG) EEG is a signal resulting from registration of the changes of electrical potentials accompanying the brain activity. Simulation techniques has been tried to understand the underlying phenomenon. A Pascal procedure has been developed to emulate the results of Wright and Kyddâ€™s description of power spectra Group structures of transition matrix suggest a possible link between the identity of the group and the phenomenon of brain death. Physiological implications of the theory are discussed
