Human body changes with aging because the cells in our body stop dividing, which results in the overall changes, be it the appearance or the bodily functions. Incidence of stroke, white matter lesions, and dementia also rise with age, as does level of memory impairment and there are changes in levels of neurotransmitters and hormones. Aging is the greatest risk factor for most common neurodegenerative diseases, including Mild cognitive impairment, Alzheimer's disease, cerebrovascular disease, Parkinson's disease and Lou Gehrig's disease.
The most widely seen cognitive change associated with ageing is that of memory. The brain shrinks with increasing age. But the changes in the brain does not occur to the same extent in all the regions. The finding that the prefrontal cortex is most affected, fits well with the cognitive changes seen in ageing, although some studies also suggest that ageing has the greatest effect in the hippocampus. Prefrontal cortex deals with the planning complex cognitive behaviors, personality expression, decision making, and moderating social behaviour whereas hippocampus is involved in the storage of long-term memory, including all the past knowledge and experiences, it also plays an important role in spatial navigation.