Determining an intended action based on one more brain signal frequencies includes establishing communication with one or more electrodes for sensing brain signals of a subject, and acquiring the brain signals via the electrodes while the subject performs at least one cognitive task, wherein the acquired brain signals having a plurality of frequencies associated therewith. A physiologic change at one or more of the plurality of frequencies may then be identified from the acquired brain signals, and the one or more of the plurality of frequencies are associated with the cognitive task.