title: Functional and effective hippocampal-neocortical connectivity during construction and elaboration of autobiographical memory retrieval.
abstract: Autobiographical memory (AM) provides the opportunity to study interactions among brain areas that support the search for a specific episodic memory (construction), and the later experience of mentally reliving it (elaboration). While the hippocampus supports both construction and elaboration, it is unclear how hippocampal-neocortical connectivity differs between these stages, and how this connectivity involves the anterior and posterior segments of the hippocampus, as these have been considered to support the retrieval of general concepts and recollection processes, respectively. We acquired fMRI data in 18 healthy participants during an AM retrieval task in which participants were asked to access a specific AM (construction) and then to recollect it by recovering as many episodic details as possible (elaboration). Using multivariate analytic techniques, we examined changes in functional and effective connectivity of hippocampal-neocortical interactions during these phases of AM retrieval. We found that the left anterior hippocampus interacted with frontal areas during construction and bilateral posterior hippocampi with visual perceptual areas during elaboration, indicating key roles for both hippocampi in coordinating transient neocortical networks at both AM stages. Our findings demonstrate the importance of direct interrogation of hippocampal-neocortical interactions to better illuminate the neural dynamics underlying complex cognitive tasks such as AM retrieval.
authors.affiliation: Krembil Neuroscience Center, Toronto Western Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada Institute of Medical Sciences.
authors.forename: Cornelia
authors.initials: C
authors.lastname: McCormick
authors.affiliation: Rotman Research Institute, Brain and Health Complex, Toronto, ON M6A 2E1, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: St-Laurent
authors.affiliation: Schulich Medicine and Dentistry, University of Western Ontario, London, ON N6A 3K6, Canada.
authors.forename: Ambrose
authors.initials: A
authors.lastname: Ty
authors.affiliation: Krembil Neuroscience Center, Toronto Western Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada Institute of Medical Sciences Department of Neurosurgery.
authors.forename: Taufik A
authors.initials: TA
authors.lastname: Valiante
authors.affiliation: Krembil Neuroscience Center, Toronto Western Research Institute, University Health Network, Toronto, ON M5T 2S8, Canada Institute of Medical Sciences Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada.
authors.forename: Mary Pat
authors.initials: MP
authors.lastname: McAndrews
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D019579:Neocortex / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D055815:Young Adult
keywords: anterior and posterior hippocampus; episodic memory; fMRI; partial least squares; structural equation modeling