A method for delivering electrical stimulation to alter a cognitive state of a user, the method comprising: monitoring a brain signal from the user via one or more intracranial electrodes implanted in the brain of the user while the user is presented with a stimulus； comparing the brain signal to a testing phase biomarker, wherein the testing phase biomarker is derived from a cognitive test performed on a contributor during a testing phase； delivering electrical stimulation to a brain of the user based on the comparing step to steer the brain of the user towards a high performance cognitive state.
