A method for identifying a functional area of a brain. The functional area is associated with a neurological function. The method includes applying a plurality of electrodes to a surface of the brain. A slow cortical potential is determined based on one or more electrical signals produced by the plurality of electrodes. A covariance pattern is computed based on the slow cortical potential, and the configuration of co-varying electrodes is used to identify one or more areas of the brain associated with the neurological function. These co-varying patterns may be used in conjunction with other electrical and/or physiological stimulation paradigms.