Research focused on discovering the genetic component in developing Autosomal Dominant (AD) has also contributed greatly to the understanding the genetics behind normal or "non-pathological" aging. Autosomal Dominant (AD) - Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. "Autosomal" means that the gene in question is located on one of the numbered, or non-sex, chromosomes. "Dominant" means that a single copy of the mutated gene (from one parent) is enough to cause the disorder.The human brain shows a decline in function and a change in gene expression. This modulation in gene expression may be due to oxidative DNA damage at promoter regions in the genome. Genes that are down-regulated over the age of 40 include:

GluR1 AMPA receptor subunit
NMDA R2A receptor subunit (involved in learning)
Subunits of the GABA-A receptor
Genes involved in long-term potentiation e.g. calmodulin 1 and CAM kinase II alpha. Calcium signaling genes
Synaptic plasticity genes
Synaptic vesicle release and recycling genesGenes that are upregulated include:

Genes associated with stress response and DNA repair
Antioxidant defence

Epigenetic age analysis of brain regions
The cerebellum is the youngest brain region (and probably body part) in centenarians according to an epigenetic biomarker of tissue age known as epigenetic clock: it is about 15 years younger than expected in a centenarian. By contrast, all brain regions and brain cells appear to have roughly the same epigenetic age in subjects who are younger than 80.
Differences in cognitive aging might be tied to the lack of or reduced access to medical care and, as a result, suffer disproportionately from negative health outcomes. As the global population grows, diversifies, and grays, there is an increasing need to understand these inequities. Race
African Americans
In the United States, Black and African American demographics disproportionately experience metabolic dysfunction with age. This has many downstream effects, but the most prominent of these is the toll on cardiovascular health. Metabolite profiles of the healthy aging index - a score that assesses neurocognitive function, among other correlates of health through the years - are associated with cardiovascular disease. Healthy cardiovascular function is critical for maintaining neurocognitive efficiency into old age. Attention, verbal learning, and cognitive set ability are related to diastolic blood pressure, triglyceride levels, and HDL cholesterol levels, respectively. Latinos
The Latino demographic is most likely to develop metabolic syndrome - the combination of high blood pressure, high blood sugar, elevated triglyceride levels, and abdominal obesity - which not only increases the risk of cardiac events and type II diabetes but also is associated with lower neurocognitive function during midlife. Among different Latin heritages, frequency of the dementia-predisposing apoE4 allele was highest for Caribbean Latinos (Cubans, Dominicans, and Puerto Ricans) and lowest among mainland Latinos (Mexicans, Central Americans, and South Americans). Conversely, frequency of the neuroprotective apoE2 allele was highest for Caribbean Latinos and lowest for those of mainland heritage. Indigenous Peoples
Indigenous populations are often understudied in research.