title: Ambivalence in rats using single-lever Skinner boxes.
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D003216:Conditioning, Operant; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D008297:Male; D051381:Rats; D012653:Self Stimulation; D013238:Stereotaxic Techniques