title: Differential contributions of hippocampus and medial prefrontal cortex to self-projection and self-referential processing.
abstract: Converging evidence points to a neural network that supports a range of abilities including remembering the past, thinking about the future, and introspecting about oneself and others. Neuroimaging studies find hippocampal activation during event construction tasks, and patients with hippocampal amnesia are impaired in their ability to (re)construct events of the past and the future. Neuroimaging studies of constructed experiences similarly implicate the medial prefrontal cortex (mPFC), but it remains unknown whether the mPFC is critical for such processes. The current study compares performance of five patients with bilateral mPFC damage, six patients with bilateral hippocampal damage, and demographically matched comparison participants on an event construction task. Participants were given a neutral cue word and asked to (re)construct events across four time conditions: real past, imagined past, imagined present, and future. These event narratives were analyzed for the number of internal and external details to quantify the extent of episodic (re)experiencing. Given the literature on the involvement of the mPFC in self-referential processing, we also analyzed the event narratives for self-references. The patients with mPFC damage did not differ from healthy comparison participants in their ability to construct highly detailed episodic events across time periods but displayed disruptions in their incorporation of the self. Patients with hippocampal damage showed the opposite pattern; they were impaired in their ability to construct highly detailed episodic events across time periods but not in their incorporation of the self. The results suggest differential contributions of hippocampus and medial prefrontal cortex to the distributed neural network for various forms of self-projection.
authors.affiliation: Neuroscience Graduate Program, University of Iowa, 357 MRC, Iowa City, IA 52242, United States.
authors.forename: Jake
authors.initials: J
authors.lastname: Kurczek
authors.affiliation: The Hockaday School, Dallas, TX 75229, United States.
authors.forename: Emily
authors.initials: E
authors.lastname: Wechsler
authors.affiliation: The Hockaday School, Dallas, TX 75229, United States.
authors.forename: Shreya
authors.initials: S
authors.lastname: Ahuja
authors.affiliation: Thomson Reuters, Rockville, MD 20850, United States.
authors.forename: Unni
authors.initials: U
authors.lastname: Jensen
authors.affiliation: Beckman Institute and the Department of Psychology, University of Illinois, United States.
authors.forename: Neal J
authors.initials: NJ
authors.lastname: Cohen
authors.affiliation: Neuroscience Graduate Program, University of Iowa, 357 MRC, Iowa City, IA 52242, United States; Department of Psychology, University of Iowa, United States; Department of Neurology, Division of Cognitive Neuroscience, University of Iowa, 2155 RCP, Iowa City, IA 52242, United States.
authors.forename: Daniel
authors.initials: D
authors.lastname: Tranel
authors.affiliation: Neuroscience Graduate Program, University of Iowa, 357 MRC, Iowa City, IA 52242, United States; Department of Neurology, Division of Cognitive Neuroscience, University of Iowa, 2155 RCP, Iowa City, IA 52242, United States; Department of Communication Sciences and Disorders, University of Iowa, 250 Hawkins Drive, Iowa City, IA 52242, United States. Electronic address: melissa-duff@uiowa.edu.
authors.forename: Melissa
authors.initials: M
authors.lastname: Duff
mesh_terms: D000368:Aged; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology*; D012649:Self Concept; D013850:Thinking / Q000502:physiology*
keywords: Hippocampus; Memory; Self-projection; Self-referential processing; mPFC