title: The essential role of primate orbitofrontal cortex in conflict-induced executive control adjustment.
abstract: Conflict in information processing evokes trial-by-trial behavioral modulations. Influential models suggest that adaptive tuning of executive control, mediated by mid-dorsal lateral prefrontal cortex (mdlPFC) and anterior cingulate cortex (ACC), underlies these modulations. However, mdlPFC and ACC are parts of distributed brain networks including orbitofrontal cortex (OFC), posterior cingulate cortex (PCC), and superior-dorsal lateral prefrontal cortex (sdlPFC). Contributions of these latter areas in adaptive tuning of executive control are unknown. We trained monkeys to perform a matching task in which they had to resolve the conflict between two behavior-guiding rules. Here, we report that bilateral lesions in OFC, but not in PCC or sdlPFC, impaired selection between these competing rules. In addition, the behavioral adaptation that is normally induced by experiencing conflict disappeared in OFC-lesioned, but remained normal in PCC-lesioned or sdlPFC-lesioned monkeys. Exploring underlying neuronal processes, we found that the activity of neurons in OFC represented the conflict between behavioral options independent from the other aspects of the task. Responses of OFC neurons to rewards also conveyed information of the conflict level that the monkey had experienced along the course to obtain the reward. Our findings indicate dissociable functions for five closely interconnected cortical areas suggesting that OFC and mdlPFC, but not PCC or sdlPFC or ACC, play indispensable roles in conflict-dependent executive control of on-going behavior. Both mdlPFC and OFC support detection of conflict and its integration with the task goal, but in contrast to mdlPFC, OFC does not retain the necessary information for conflict-induced modulation of future decisions.
authors.affiliation: Cognitive Brain Mapping Laboratory, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Department of Physiology, Monash University, Clayton, Victoria 3800, Australia farshad.mansouri@monash.edu.
authors.forename: Farshad A
authors.initials: FA
authors.lastname: Mansouri
authors.affiliation: Department of Experimental Psychology, Oxford University, Oxford OX1 3UD, United Kingdom, and.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Buckley
authors.affiliation: Cognitive Brain Mapping Laboratory, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003220:Conflict, Psychological; D056344:Executive Function / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012201:Reward
keywords: conflict; executive control; lesion study; orbitofrontal cortex