We propose a theoretical framework for EEG and MEG based on transmission line model and cortical network activity. Using known properties of forward and backward propagating waves, an electromagnetic-physiological theory of "brain waves" based on known (but highly idealized) properties of synaptic action has been formulated which could potentially account for some experimental findings as well as can predict several salient features. We conjecture that brain waves can be treated as "Bloch waves" which may provide an important mechanism for a large scale integration required between the constantly interacting areas of the brain. © 2010 IEEE.