1 Intramural Research Program of the National Institute on Drug Abuse, Baltimore, MD, USA. wenhui.zong@nih.gov.
2 State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University & Chinese Institute of Brain Research, Beijing, China.
3 Concordia University, Montréal, Québec, Canada.
4 Intramural Research Program of the National Institute on Drug Abuse, Baltimore, MD, USA.
5 University of Alabama Birmingham, Birmingham, AL, USA.
6 Intramural Research Program of the National Institute on Drug Abuse, Baltimore, MD, USA. geoffrey.schoenbaum@nih.gov.

Both the orbitofrontal cortex (OFC) and the hippocampus (HC) are implicated in the formation of cognitive maps and their generalization into schemas. However, how these areas interact in supporting this function remains unclear, with some proposals supporting a serial model in which the OFC draws on task representations created by the HC to extract key behavioral features and others suggesting a parallel model in which both regions construct representations that highlight different types of information. In the present study, we tested between these two models by asking how schema correlates in rat OFC would be affected by inactivating the output of the HC, after learning and during transfer across problems. We found that the prevalence and content of schema correlates were unaffected by inactivating one major HC output area, the ventral subiculum, after learning, whereas inactivation during transfer accelerated their formation. These results favor the proposal that the OFC and HC operate in parallel to extract different features defining cognitive maps and schemas.