Differential representation of Pavlovian-instrumental transfer by prefrontal cortex subregions and striatum.
Environmental cues that once predicted reward can restore extinguished behavior directed toward that reward. This process may be modeled by the Pavlovian-instrumental transfer (PIT) paradigm where a previously learned Pavlovian conditioned stimulus (CS) elicits a representation of the reward associated with that CS, prompts motivation toward the absent reward, and triggers an instrumental action. We recorded in the medial and orbital prefrontal cortex (mPFC and OFC) and dorsal striatum (DS) of freely moving rats during PIT and found that a Pavlovian CS, as compared with neutral or no stimuli, amplified the phasic neuronal responses to instrumental nosepokes ('transfer' event). In mPFC and OFC, but not the DS, representation of the transfer event correlated with the strength of PIT behavior. Neurons in all three regions showed CS-selective amplification of Pavlovian approaches toward the reward delivery site. Whereas striatal neurons represented transfer and approach behavior through mostly segregated neuronal subsets, overlapping subsets represented these events in the mPFC and OFC. These findings suggest that parallel phasic activation of mPFC and OFC neuronal subsets participates in the transfer from Pavlovian incentives to instrumental actions.
Homayoun
Houman
H
Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA. homayounh@upmc.edu
Moghaddam
Bita
B
D000200:Action Potentials; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D016291:Dizocilpine Maleate / Q000008:administration & dosage; D004567:Electrodes, Implanted; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D013997:Time Factors; D014163:Transfer, Psychology / Q000187:drug effects / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D016291:Dizocilpine Maleate