title: Hippocampal neural correlates for values of experienced events.
abstract: Newly experienced events are often remembered together with how rewarding the experiences are personally. Although the hippocampus is a candidate structure where subjective values are integrated with other elements of episodic memory, it is uncertain whether and how the hippocampus processes value-related information. We examined how activity of dorsal CA1 and dorsal subicular neurons in rats performing a dynamic foraging task was related to reward values that were estimated using a reinforcement learning model. CA1 neurons carried significant signals related to action values before the animal revealed its choice behaviorally, indicating that the information on the expected values of potential choice outcomes was available in CA1. Moreover, after the outcome of the animal's goal choice was revealed, CA1 neurons carried robust signals for the value of chosen action and they temporally overlapped with the signals related to the animal's goal choice and its outcome, indicating that all the signals necessary to evaluate the outcome of an experienced event converged in CA1. On the other hand, value-related signals were substantially weaker in the subiculum. These results suggest a major role of CA1 in adding values to experienced events during episodic memory encoding. Given that CA1 neuronal activity is modulated by diverse attributes of an experienced event, CA1 might be a place where all the elements of episodic memory are integrated.
authors.affiliation: Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea.
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Lee
authors.forename: Jeong-Wook
authors.initials: JW
authors.lastname: Ghim
authors.forename: Hoseok
authors.initials: H
authors.lastname: Kim
authors.forename: Daeyeol
authors.initials: D
authors.lastname: Lee
authors.forename: MinWhan
authors.initials: M
authors.lastname: Jung
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D058256:Brain Waves / Q000502:physiology; D002755:Choice Behavior / Q000502:physiology*; D003214:Conditioning, Classical; D006624:Hippocampus / Q000166:cytology*; D016015:Logistic Models; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D013037:Spatial Behavior / Q000502:physiology*; D014868:Water Deprivation / Q000502:physiology