Brain Aging: Difference between revisions

# '''Tactile function''': the ability to feel and respond to sensations of touch, including pressure, pain, and temperature.<ref>Cognitive Health and Older Adults. https://www.nia.nih.gov/health/cognitive-health-and-older-adults (accessed Apr 26, 2023).</ref>

At the molecular level, brain aging, similarly to all other organ systems, is characterized by changes in gene expression, [[Epigenetic Alterations|epigenetic modifications]], and [[Loss of Proteostasis|alterations in protein synthesis]] and turnover. It is also associated with the accumulation of toxic protein aggregates, such as β-amyloid and tau, which can disrupt neuronal function and contribute to the development of [[Neurodegenerative Disorders|neurodegenerative diseases]].{{pmid|34118939}}{{pmid|34485280}} At the cellular level, brain aging is characterized by the accumulation of cell damage, including oxidative stress, DNA damage, and protein misfolding. This damage can lead to the dysfunction and death of brain cells, including neurons and glia. Studies have shown that dendritic arbors and spines decrease in size and/or number in cortex as a result of aging.{{pmid|12902394}}{{pmid|23069756}} Aging also sets off a decline in the regenerative capacity of brain cells, such as decreased neurogenesis and oligodendrogenesis.{{pmid|33732142}}{{pmid|25205996}}

At the system level, brain aging includes changes in brain connectivity and function such as alterations in neural activity, neurotransmitter function, and white matter integrity. Aging is associated with a decline in the function of essential neurotransmitter systems such as dopamine and acetylcholine, which can lead to cognitive impairment. Brain aging is associated also with changes in brain structure, such as the loss of gray matter volume and changes in white matter microstructure.{{pmid|29874566}}{{pmid|16461469}}{{pmid|12548289}} At the organismal level, brain aging is associated with declines in cognitive function, sensory function, and motor function. Age-related changes in the cardiovascular system, immune system, and endocrine system can also impact brain function and contribute to age-related [[Neurodegenerative Disorders|neurodegenerative diseases]].{{pmid|34485280}}{{pmid|34600936}}

[[Hallmarks of Aging|Hallmarks of aging]], including mitophagy, [[Cellular Senescence|cellular senescence]], [[Genomic Instability|genomic instability]], and protein aggregation, have been related to the age-associated neurodegenerative and cerebrovascular disorders.{{pmid|31501588}} Furthermore, the most frequent neurodegenerative diseases share the common attribute of protein aggregation. The aggregation of senile plaques containing amyloid-β peptide and the formation of intraneuronal tau containing neurofibrillary tangles in Alzheimer’s disease and the accumulation of misfolded α-synuclein in Parkinson’s disease are major pathogenic aspects of these diseases.{{pmid|26209472}} Protein aggregation is also a feature of amyotrophic lateral sclerosis and frontotemporal lobar dementia.{{pmid|27540165}}