title: Identification of an unconventional process of instrumental learning characteristically initiated with outcome devaluation-insensitivity and generalized action selection.
abstract: The distinction between goal-directed action and habitual response, particularly with respect to moderate or extended appetitive instrumental training, is well documented; however, the propensity toward instrumental behavior in the early training stage has not been elucidated. In this study, we trained Sprague Dawley rats to press a lever to obtain food as an outcome for various time periods and monitored the changes in their sensitivity to outcome devaluation and choice between the levers they had been trained with and unfamiliar levers. After the extensive training with a random interval schedule, the rats were insensitive to outcome devaluation, and exhibited a typical habit-like phenotype, as previously reported, and the untrained leverpresses were relatively rare and sporadic. During the initial stage of training (≤1 week), the rats exhibited a similar insensitivity to the devaluation; however, in contrast to the overtrained condition, they performed distinctive unbiased leverpresses on both the trained and untrained levers. Thus, we propose a possibility that, contrary to the authentic concept that instrumental learning is initiated with an outcome devaluation-sensitive goal-directed stage, under some conditions, this learning can unconventionally begin with the initial stage that is distinct from both goal-directed action and habitual response.
authors.affiliation: Department of Psychiatry &Behavioral Science, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.|Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University, Fukushima, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Iguchi
authors.affiliation: Department of Psychiatry &Behavioral Science, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.
authors.forename: Ziqiao
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Psychiatry &Behavioral Science, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nishikawa
authors.affiliation: Department of Psychiatry &Behavioral Science, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.|Research Center for Child Mental Development, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Minabe
authors.affiliation: Department of Psychiatry &Behavioral Science, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.|Research Center for Child Mental Development, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Toda
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002755:Choice Behavior / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology*; D003657:Decision Making / Q000502:physiology; D005108:Extinction, Psychological / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D006184:Habits; D008297:Male; D009042:Motivation / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology