title: Schema representation in patients with ventromedial PFC lesions.
abstract: Human neuroimaging and animal studies have recently implicated the ventromedial prefrontal cortex (vmPFC) in memory schema, particularly in facilitating new encoding by existing schemas. In humans, the most conspicuous memory disorder following vmPFC damage is confabulation; strategic retrieval models suggest that aberrant schema activation or reinstatement plays a role in confabulation. This raises the possibility that beyond its role in schema-supported memory encoding, the vmPFC is also implicated in schema reinstatement itself. If that is the case, vmPFC lesions should lead to impaired schema-based operations, even on tasks that do not involve memory acquisition. To test this prediction, ten patients with vmPFC damage, four with present or prior confabulation, and a group of twelve matched healthy controls made speeded yes/no decisions as to whether words were closely related to a schema (a visit to the doctor). Ten minutes later, they repeated the task for a new schema (going to bed) with some words related to the first schema included as lures. Last, they rated the degree to which stimuli were related to the second schema. All four vmPFC patients with present or prior confabulation were impaired in rejecting lures and in classifying stimulus belongingness to the schema, even when they were not lures. Nonconfabulating patients performed comparably to healthy adults with high accuracy, comparable reaction times, and similar ratings. These results show for the first time that damage to the human vmPFC, when associated with confabulation, leads to deficient schema reinstatement, which is likely a prerequisite for schema-mediated memory integration.
authors.affiliation: University of Toronto, Toronto, Ontario M5S 3G3, Canada, Rotman Research Institute at Baycrest Hospital, Toronto, Ontario M6A 2E1, Canada.
authors.forename: Vanessa E
authors.initials: VE
authors.lastname: Ghosh
authors.affiliation: University of Toronto, Toronto, Ontario M5S 3G3, Canada, Rotman Research Institute at Baycrest Hospital, Toronto, Ontario M6A 2E1, Canada.
authors.forename: Morris
authors.initials: M
authors.lastname: Moscovitch
authors.affiliation: Toronto Rehabilitation Institute, Toronto, Ontario M5G 2A2, Canada, and.
authors.forename: Brenda
authors.initials: B
authors.lastname: Melo Colella
authors.affiliation: University of Toronto, Toronto, Ontario M5S 3G3, Canada, Rotman Research Institute at Baycrest Hospital, Toronto, Ontario M6A 2E1, Canada, Canadian Partnership for Stroke Recovery, Ottawa, Ontario K1G 5Z3, Canada agilboa@research.baycrest.org.
authors.forename: Asaf
authors.initials: A
authors.lastname: Gilboa
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003071:Cognition; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008568:Memory; D008569:Memory Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008875:Middle Aged; D011930:Reaction Time
keywords: confabulation; lesion study; schema; subgenual anterior cingulate; ventromedial prefrontal cortex