title: Dissociation Of working memory from decision making within the human prefrontal cortex.
abstract: We tested the hypothesis that cognitive functions related to working memory (assessed with delay tasks) are distinct from those related to decision making (assessed with a gambling task), and that working memory and decision making depend in part on separate anatomical substrates. Normal controls (n = 21), subjects with lesions in the ventromedial (VM) (n = 9) or dorsolateral/high mesial (DL/M) prefrontal cortices (n = 10), performed on (1) modified delay tasks that assess working memory and (2) a gambling task designed to measure decision making. VM subjects with more anterior lesions (n = 4) performed defectively on the gambling but not the delay task. VM subjects with more posterior lesions (n = 5) were impaired on both tasks. Right DL/M subjects were impaired on the delay task but not the gambling task. Left DL/M subjects were not impaired on either task. The findings reveal a cognitive and anatomic double dissociation between deficits in decision making (anterior VM) and working memory (right DL/M). This presents the first direct evidence of such effects in humans using the lesion method and underscores the special importance of the VM prefrontal region in decision making, independent of a direct role in working memory.
authors.affiliation: Department of Neurology, Division of Behavioral Neurology and Cognitive Neuroscience, University of Iowa College of Medicine, Iowa City, Iowa, 52242, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bechara
authors.forename: H
authors.initials: H
authors.lastname: Damasio
authors.forename: D
authors.initials: D
authors.lastname: Tranel
authors.forename: S W
authors.initials: SW
authors.lastname: Anderson
mesh_terms: D000328:Adult; D000368:Aged; D001925:Brain Damage, Chronic / Q000503:physiopathology*; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003657:Decision Making; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D005715:Gambling; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology