Grey and white matter correlates of recent and remote autobiographical memory retrieval--insights from the dementias.
The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events.
School of Psychology, the University of New South Wales, Sydney, Australia; Neuroscience Research Australia, Randwick, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia.
Muireann
M
Irish
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia; Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom.
Michael
M
Hornberger
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia.
Shadi
S
El Wahsh
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia.
Bonnie Y K
BY
Lam
Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia; School of Psychology, the University of Sydney, Sydney, Australia.
Suncica
S
Lah
Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia; Neuropsychology Unit, Royal Prince Alfred Hospital, and Central Clinical School, University of Sydney, Sydney, Australia.
Laurie
L
Miller
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia.
Sharpley
S
Hsieh
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia.
John R
JR
Hodges
Neuroscience Research Australia, Randwick, Sydney, Australia; School of Medical Sciences, the University of New South Wales, Sydney, Australia; Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia.
Olivier
O
Piguet
D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D001921:Brain / Q000000981:diagnostic imaging; D001931:Brain Mapping; D016022:Case-Control Studies; D003704:Dementia / Q000503:physiopathology*; D005260:Female; D057180:Frontotemporal Dementia / Q000503:physiopathology; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests; D011859:Radiography; D066127:White Matter / Q000000981:diagnostic imaging / Q000503:physiopathology*