title: Using fMRI to understand event construction in developmental amnesia.
abstract: Recently, neuroimaging and patient-lesion methods have been combined to explain anomalies such as patients' intact performance on tasks on which they would be predicted to perform poorly. In some cases, preserved performance has been attributed to activation of residual tissue within the damaged region. However, activation of remnant tissue can also occur in relation to impaired performance and, thus, may not necessarily correspond to successful recruitment. To constrain these neuroimaging interpretations, what is needed is a paradigm with closely matched conditions that yields intact and impaired performance in the same patient. We investigated this in H.C., an amnesic person with congenital abnormalities of the hippocampus and its connections, who was scanned during remembering and imagining, abilities known to depend on the hippocampus. Specifically, we examined whether differences in activation and/or functional connectivity would explain H.C.'s compromised ability to construct events relating to herself in autobiographical memory (SELF condition) and events relating to personally familiar others (FAMILIAR condition) versus her intact ability to construct events relating to unknown others (UNFAMILIAR condition). Despite behavioral dissociations in H.C., the pattern of activation and functional connectivity supporting her performance was strikingly similar to that of controls across conditions. Most notably, like controls, H.C. showed robust hippocampal activation and functional connectivity to the hippocampus, both when her performance was intact and impaired. Across all conditions, H.C. activated several extra-hippocampal regions to a greater extent than did controls, and modest differences were observed in functional connectivity between extra-hippocampal regions. Taken together, these findings urge caution when drawing conclusions about the functional integrity of a structurally compromised brain region even when it is activated and/or co-activated with other regions.
authors.affiliation: Department of Psychology, York University, Toronto, ON, Canada M3J 1P3.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Rabin
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, ON, Canada M6A 2E1; Department of Psychology, University of Toronto, Toronto, ON, Canada M5S 1A1.
authors.forename: Rosanna K
authors.initials: RK
authors.lastname: Olsen
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, ON, Canada M6A 2E1; Department of Psychology, University of Toronto, Toronto, ON, Canada M5S 1A1; The Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, ON, Canada.
authors.forename: Asaf
authors.initials: A
authors.lastname: Gilboa
authors.affiliation: Rotman Research Institute, Baycrest, Toronto, ON, Canada M6A 2E1; Department of Psychology, University of Toronto, Toronto, ON, Canada M5S 1A1.
authors.forename: Bradley R
authors.initials: BR
authors.lastname: Buchsbaum
authors.affiliation: Department of Psychology, York University, Toronto, ON, Canada M3J 1P3; Rotman Research Institute, Baycrest, Toronto, ON, Canada M6A 2E1; The Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, ON, Canada.
authors.forename: R Shayna
authors.initials: RS
authors.lastname: Rosenbaum
mesh_terms: D000647:Amnesia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D021641:Recognition, Psychology / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Autobiographical memory; Case study; Developmental amnesia; Hippocampus; Imagining; fMRI