1. A method for treating a patient having a subject neural population in a first hemisphere of the patient's brain, wherein the subject neural population has or had a functionality that is capable of being improved, the method comprising: directing an application of electromagnetic signals at least proximate to a target neural population via at least one electrode implanted in the patient to at least constrain a functionality of the target neural population, the target neural population being at a second hemisphere of the brain and having transcallosal communication with the first hemisphere.