title: Preservation of neuronal number despite age-related cortical brain atrophy in elderly subjects without Alzheimer disease.
abstract: Cerebral volume loss has long been associated with normal aging, but whether this is due to aging itself or to age-related diseases, including incipient Alzheimer disease, is uncertain. To understand the changes that occur in the aging brain, we examined the cerebral cortex of 27 normal individuals ranging in age from 56 to 103 years. None fulfilled the criteria for the neuropathologic diagnosis of Alzheimer disease or other neurodegenerative disease. Seventeen of the elderly participants had cognitive testing an average of 6.7 months prior to death. We used quantitative approaches to analyze cortical thickness, neuronal number, and density. Frontal and temporal neocortical regions had clear evidence of cortical thinning with age, but total neuronal numbers in frontal and temporal neocortical regions remained relatively constant during a 50-year age range. These data suggest that loss of neuronal and dendritic architecture, rather than loss of neurons, underlies neocortical volume loss with increasing age in the absence of Alzheimer disease.
authors.affiliation: C.S. Kubik Laboratory for Neuropathology, Department of Pathology, Alzheimer Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA. freestefanie@gmail.com
authors.forename: Stefanie H
authors.initials: SH
authors.lastname: Freeman
authors.forename: Ruth
authors.initials: R
authors.lastname: Kandel
authors.forename: Luis
authors.initials: L
authors.lastname: Cruz
authors.forename: Anete
authors.initials: A
authors.lastname: Rozkalne
authors.forename: Kathy
authors.initials: K
authors.lastname: Newell
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Frosch
authors.forename: E Tessa
authors.initials: ET
authors.lastname: Hedley-Whyte
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Locascio
authors.forename: Lewis A
authors.initials: LA
authors.lastname: Lipsitz
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Hyman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000473:pathology; D001284:Atrophy / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D002452:Cell Count; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D003712:Dendrites / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D009410:Nerve Degeneration / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000473:pathology*; D009483:Neuropsychological Tests