Life and Death of Neurons in the Aging Brain

• Published in: Science (American Association for the Advancement of Science) 1997-10, Vol.278 (5337), p.412-419
• Main Authors: Morrison, John H., Hof, Patrick R.
• Format: Article
• Language: English
• Subjects: Advances in Aging Research; Aging; Aging (Biology); Aging (Individuals); Alzheimer Disease - pathology; Alzheimer's disease; Alzheimers Disease; Animals; Behavioral neuroscience; Biochemistry; Biological and medical sciences; Brain; Cell Death; Cell Survival; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dementia; Dentate gyrus; Entorhinal Cortex - pathology; Estrogens - physiology; Female; Hippocampus; Hippocampus - cytology; Hippocampus - pathology; Hippocampus - physiology; Humans; Life Sciences (General); Male; Medical sciences; Memory; Molecular biology; Neocortex; Neocortex - cytology; Neocortex - pathology; Neocortex - physiology; Nerve Degeneration; Neurobiology; Neurochemistry; Neurodegenerative diseases; Neurofibrillary Tangles - pathology; Neurofilament proteins; Neurofilament Proteins - metabolism; Neurology; Neurons; Neurons - cytology; Neurons - pathology; Neurons - physiology; Perforant pathway; Space life sciences
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.278.5337.412

Neurodegenerative disorders are characterized by extensive neuron death that leads to functional decline, but the neurobiological correlates of functional decline in normal aging are less well defined. For decades, it has been a commonly held notion that widespread neuron death in the neocortex and hippocampus is an inevitable concomitant of brain aging, but recent quantitative studies suggest that neuron death is restricted in normal aging and unlikely to account for age-related impairment of neocortical and hippocampal functions. In this article, the qualitative and quantitative differences between aging and Alzheimer's disease with respect to neuron loss are discussed, and age-related changes in functional and biochemical attributes of hippocampal circuits that might mediate functional decline in the absence of neuron death are explored. When these data are viewed comprehensively, it appears that the primary neurobiological substrates for functional impairment in aging differ in important ways from those in neurodegenerative disorders such as Alzheimer's disease.