Rats learning to work for alcohol.
D000428:Alcohol Drinking; D000818:Animals; D002940:Circadian Rhythm; D003216:Conditioning, Operant; D004193:Discrimination Learning; D008297:Male; D009042:Motivation; D009994:Osmolar Concentration; D005082:Physical Exertion; D051381:Rats; D012055:Reinforcement Schedule; D012193:Reversal Learning