title: Hippocampal formation alterations differently contribute to autobiographic memory deficits in mild cognitive impairment and Alzheimer's disease.
abstract: Autobiographical memory (AM) is part of declarative memory and includes both semantic and episodic aspects. AM deficits are among the major complaints of patients with Alzheimer's disease (AD) even in early or preclinical stages. Previous MRI studies in AD patients have showed that deficits in semantic and episodic AM are associated with hippocampal alterations. However, the question which specific hippocampal subfields and adjacent extrahippocampal structures contribute to deficits of AM in individuals with mild cognitive impairment (MCI) and AD patients has not been investigated so far. Hundred and seven participants (38 AD patients, 38 MCI individuals and 31 healthy controls [HC]) underwent MRI at 3 Tesla. AM was assessed with a semi-structured interview (E-AGI). FreeSurfer 5.3 was used for hippocampal parcellation. Semantic and episodic AM scores were related to the volume of 5 hippocampal subfields and cortical thickness in the parahippocampal and entorhinal cortex. Both semantic and episodic AM deficits were associated with bilateral hippocampal alterations. These associations referred mainly to CA1, CA2-3, presubiculum, and subiculum atrophy. Episodic, but not semantic AM loss was associated with cortical thickness reduction of the bilateral parahippocampal and enthorinal cortex. In MCI individuals, episodic, but not semantic AM deficits were associated with alterations of the CA1, presubiculum and subiculum. Our findings support the crucial role of CA1, presubiculum, and subiculum in episodic memory. The present results implicate that in MCI individuals, semantic and episodic AM deficits are subserved by distinct neuronal systems.
authors.affiliation: Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany.|Department of General Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Germany.
authors.forename: Dusan
authors.identifier: 0000-0003-1226-9800
authors.initials: D
authors.lastname: Hirjak
authors.affiliation: Department of General Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Germany.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Wolf
authors.affiliation: Department of General Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Remmele
authors.affiliation: Department of Psychiatry, Center for Mental Health, Stuttgart, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Seidl
authors.affiliation: Department of Internal Medicine II, Medical Faculty Mannheim, University of Heidelberg, Germany.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Thomann
authors.affiliation: Department of General Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Germany.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Kubera
authors.affiliation: Section of Geriatric Psychiatry, Heidelberg University, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schröder
authors.affiliation: Medical Image Computing Group, Division Medical and Biological Informatics, German Cancer Research Center (DKFZ), Germany.
authors.forename: Klaus H
authors.initials: KH
authors.lastname: Maier-Hein
authors.affiliation: Department of General Psychiatry, Center for Psychosocial Medicine, University of Heidelberg, Germany.|Center for Mental Health, Odenwald District Healthcare Center, Albert-Schweitzer-Straße 10-20, Erbach, 64711, Germany.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Thomann
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged
keywords: Alzheimer's disease; Freesurfer; MRI; autobiographical memory; hippocampus; mild cognitive impairment