Because it's there.
D032761:Animal Experimentation; D000818:Animals; D032763:Behavior Control / Q000379:methods*; D001522:Behavior, Animal; D001921:Brain / Q000502:physiology; D004567:Electrodes, Implanted; D005380:Financing, Government; D006801:Humans; D011846:Radio Waves; D051381:Rats; D012109:Research Support as Topic; D014481:United States