title: Testing necessary regional frontal contributions to value assessment and fixation-based updating.
abstract: Value-based decisions are biased by the time people spend viewing each option: Options fixated longer are chosen more often, even when previously rated as less appealing. This bias is thought to reflect 'value updating' as new evidence is accumulated. Prior work has shown that ventromedial prefrontal cortex (PFC) carries a fixation-dependent value comparison signal, while other studies implicate dorsomedial PFC in representing the value of alternative options. Here, we test whether these regions are necessary for fixation-related value updating in 33 people with frontal lobe damage and 27 healthy controls performing a simple choice task. We show that damage to dorsomedial PFC leads to an exaggerated influence of fixations on choice, while damage to ventromedial or lateral PFC has no effect on this bias. These findings suggest a critical role for dorsomedial, and not ventromedial PFC, in mediating the relative influence of current fixations and a priori value on choice.
authors.affiliation: Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
authors.forename: Avinash R
authors.initials: AR
authors.lastname: Vaidya
authors.affiliation: Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
authors.forename: Lesley K
authors.initials: LK
authors.lastname: Fellows
mesh_terms: D001288:Attention / Q000502:physiology; D001930:Brain Injuries / Q000503:physiopathology / Q000523:psychology; D001931:Brain Mapping; D016022:Case-Control Studies; D003657:Decision Making / Q000502:physiology*; D005625:Frontal Lobe / Q000473:pathology* / Q000502:physiology*; D006801:Humans; D008960:Models, Psychological