Preservation of neuronal number despite age-related cortical brain atrophy in elderly subjects without Alzheimer disease.
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.
Freeman
Stefanie H
SH
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
Kandel
Ruth
R
Cruz
Luis
L
Rozkalne
Anete
A
Newell
Kathy
K
Frosch
Matthew P
MP
Hedley-Whyte
E Tessa
ET
Locascio
Joseph J
JJ
Lipsitz
Lewis A
LA
Hyman
Bradley T
BT
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