title: Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging.
abstract: Decline in cognitive skills, especially in memory, is often viewed as part of "normal" aging. Yet some individuals "age better" than others. Building on prior research showing that cortical thickness in one brain region, the anterior midcingulate cortex, is preserved in older adults with memory performance abilities equal to or better than those of people 20-30 years younger (i.e., "superagers"), we examined the structural integrity of two large-scale intrinsic brain networks in superaging: the default mode network, typically engaged during memory encoding and retrieval tasks, and the salience network, typically engaged during attention, motivation, and executive function tasks. We predicted that superagers would have preserved cortical thickness in critical nodes in these networks. We defined superagers (60-80 years old) based on their performance compared to young adults (18-32 years old) on the California Verbal Learning Test Long Delay Free Recall test. We found regions within the networks of interest where the cerebral cortex of superagers was thicker than that of typical older adults, and where superagers were anatomically indistinguishable from young adults; hippocampal volume was also preserved in superagers. Within the full group of older adults, thickness of a number of regions, including the anterior temporal cortex, rostral medial prefrontal cortex, and anterior midcingulate cortex, correlated with memory performance, as did the volume of the hippocampus. These results indicate older adults with youthful memory abilities have youthful brain regions in key paralimbic and limbic nodes of the default mode and salience networks that support attentional, executive, and mnemonic processes subserving memory function.
  
  
  
  Memory performance typically declines with age, as does cortical structural integrity, yet some older adults maintain youthful memory. We tested the hypothesis that superagers (older individuals with youthful memory performance) would exhibit preserved neuroanatomy in key brain networks subserving memory. We found that superagers not only perform similarly to young adults on memory testing, they also do not show the typical patterns of brain atrophy in certain regions. These regions are contained largely within two major intrinsic brain networks: the default mode network, implicated in memory encoding, storage, and retrieval, and the salience network, associated with attention and executive processes involved in encoding and retrieval. Preserved neuroanatomical integrity in these networks is associated with better memory performance among older adults.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and Psychiatric Neuroimaging Division, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and.
authors.forename: Felicia W
authors.initials: FW
authors.lastname: Sun
authors.affiliation: Frontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Stepanovic
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and Psychiatric Neuroimaging Division, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and Department of Psychology, Northeastern University, Boston, Massachusetts 02115.
authors.forename: Joseph
authors.initials: J
authors.lastname: Andreano
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and Psychiatric Neuroimaging Division, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and Department of Psychology, Northeastern University, Boston, Massachusetts 02115 atouroutoglou@mgh.harvard.edu l.barrett@northeastern.edu brad.dickerson@mgh.harvard.edu.
authors.forename: Lisa Feldman
authors.initials: LF
authors.lastname: Barrett
authors.affiliation: Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and atouroutoglou@mgh.harvard.edu l.barrett@northeastern.edu brad.dickerson@mgh.harvard.edu.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Touroutoglou
authors.affiliation: Frontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, and atouroutoglou@mgh.harvard.edu l.barrett@northeastern.edu brad.dickerson@mgh.harvard.edu.
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Dickerson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009434:Neural Pathways / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D009483:Neuropsychological Tests; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult
keywords: aging; cerebral cortex; default mode network; memory; salience network