Repeated variations in deprivation level: different effects depending on amount of training.
D000222:Adaptation, Physiological; D000818:Animals; D003216:Conditioning, Operant; D004193:Discrimination Learning; D005502:Food; D005508:Food Deprivation; D006234:Handling, Psychological; D006815:Hunger; D008297:Male; D009042:Motivation; D009043:Motor Activity; D051381:Rats; D011919:Rats, Inbred Strains; D012054:Reinforcement, Psychology; D013997:Time Factors