Not all brains age the same, just as not all bodies age the same.
Intense basic and clinical research aims at understanding the “normal” changes in brain structure and function that are associated with aging and why the aged brain is more susceptible to many neurological disorders. While there are some generalizations that can be made about the physical changes the brain undergoes as it ages. Such as decreased levels of certain neurotransmitters or degradation of discrete neuron populations, there is also wide variation in how those physical changes impact cognitive function. In other words, everyone’s brain ages differently.
The good news is that the brain is adaptable at any age. It continues to add and modify its synapses and neural pathways throughout life, in an experience-dependent manner.
That means “use it or lose it”! Brain pathways that are inactive are eventually lost, while an enriching and stimulating life creates a richer network of synapses. This may act as a “neural reserve” against cognitive decline: if the brain is flush with neural pathways then it may be able to use alternate routes to accomplish tasks, like taking a detour around a highway that’s jammed with traffic or under construction.
There have now been a number of cases reported in the scientific literature of older people who had normal or near-normal cognitive function at death, but whose autopsy studies showed extensive brain damage such as what might occur in Alzheimer’s disease. It’s as if their brains had found a way to adapt to a degree of disease pathology that would typically cause severe impairment.