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Life and Death of Neurons in the Aging Cerebral Cortex
Author(s) -
Morrison John H.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a136-a
Subject(s) - neuroscience , hippocampal formation , cognition , disconnection , degeneration (medical) , hippocampus , psychology , disease , cerebral cortex , cognitive decline , dementia , medicine , pathology , political science , law
The human brain is uniquely powerful with respect to cognitive abilities, yet the hippocampal and neocortical circuits that mediate such complex functions are highly vulnerable to aging. In order to understand normal aging, it is instructive to review the major elements of circuit degeneration associated with a neurodegenerative disorder such as Alzheimer's disease (AD). The corticocortical circuits and the pyramidal neurons that provide them are the key to the functional deficits seen in both AD and normal aging. The selective vulnerability of these neurons is profoundly manifested in AD, where degeneration of select neurons leads to a disconnection of cortical regions from each other, and the near complete loss of cognitive abilities. Most of us will avoid AD as we age. However, many will experience age‐associated cognitive impairment, a decline in cognitive status, memory, and the capacity for strategic use of acquired information. Animal studies suggest that the same neurons and circuits that degenerate in AD are vulnerable in normal aging, however, while neuron death predominates in AD, age‐associated cognitive impairment is likely mediated by synaptic alterations in otherwise intact circuits. Fortunately, such age‐related synaptic alterations may be preventable or reversible, as suggested by recent studies of hormone replacement.