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: identifying an ipsilesional target neural population on a first hemisphere; identifying a contralesional target neural population on a second hemisphere having transcallosal communication with the first hemisphere; facilitating functionality of the ipsilesional neural population by directing an application of first, facilitatory electromagnetic signals to the ipsilesional neural population of the first hemisphere such that the facilitatory signals are cathodal signals having a frequency of 50 Hz to 100 Hz; and constraining functionality of the contralesional neural population by directing an application of second electromagnetic signals to inhibit, disrupt or depotentiate the contralesional target neural population via a transcranial magnetic device and the second signals are anodal signals having a frequency of 1 Hz to 10 Hz thereby improving functionality of the patient.