How does aging affect the brain

Dementia prevention, intervention, and care: report of the Lancet Commissions. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Alzheimer's Disease and Healthy Aging. Section Navigation. Facebook Twitter LinkedIn Syndicate. The Truth About Aging and Dementia. Minus Related Pages. Signs to watch for include: Alzheimer's disease or related dementias are not an inevitable part of aging. For more information, see What Is Dementia? When the timing is right, talk about issues related to safety including driving and carrying identification. Symptoms of dementia include getting lost in familiar places, difficulty judging distance, determining color or contrast, and reading which can make driving especially difficult.

Slowing of thought, memory, and thinking is a normal part of aging. These changes are not the same in everyone. Some people have many changes in their nerves and brain tissue. Others have few changes. These changes are not always related to the effects on your ability to think.

Dementia and severe memory loss are not a normal part of aging. They can be caused by brain diseases such as Alzheimer disease , which doctors believe is associated with plaques and tangles forming in the brain.

Delirium is sudden confusion that leads to changes in thinking and behavior. It is often due to illnesses that are not related to the brain. Infection can cause an older person to become severely confused.

Certain medicines can also cause this. Thinking and behavior problems can also be caused by poorly controlled diabetes. Rising and falling blood sugar levels can interfere with thought. Seek medical help right away if these symptoms occur suddenly or along with other symptoms. A change in thinking, memory, or behavior is important if it is different from your normal patterns or it affects your lifestyle.

Differential diagnosis of spinal disease. Some studies suggest a slow decline starts as early as age Working memory depends on the rapid processing of new information rather than on stored knowledge. Other aspects of this kind of fluid intelligence, such as processing speed and problem-solving, also decrease with age. Certain aspects of attention can become more difficult as our brains age. Our ability to tune out distractions and focus on a particular stimulus is called selective attention.

Splitting our focus between two tasks — like holding a conversation while driving — also becomes more challenging with age. This type of attention is called divided attention. In fact, certain cognitive abilities improve in middle age: the Seattle Longitudinal Study, which tracked the cognitive abilities of thousands of adults over the past 50 years, showed people actually performed better on tests of verbal abilities, spatial reasoning, math, and abstract reasoning in middle age than they did when they were young adults.

As we enter midlife, our brains change in subtle but measurable ways. The prefrontal cortex , cerebellum , and hippocampus show the biggest losses, which worsen in advanced age. Our cerebral cortex , the wrinkled outer layer of the brain containing neuron cell bodies, also thins as we age.

Cortical thinning follows a pattern similar to volume loss and is especially pronounced in the frontal lobes and parts of the temporal lobes. The areas of the brain that experience the most dramatic changes with age are also among the last to mature in adolescence. Studies of age-related changes to white matter support this hypothesis. Fibers connecting diffuse areas within a single hemisphere — called association fibers — are the last to reach maturity and show the steepest functional declines with age.

Changes at the level of individual neurons contribute to the shrinkage and cortical thinning of the aging brain. Neurons shrink and retract their dendrites, and the fatty myelin that wraps around axons deteriorates. The number of connections, or synapses, between brain cells also drops, which can affect learning and memory. Although synaptic changes are selective and subtle, their effect on cognitive decline is believed to be greater than the effects of structural and chemical changes.

In the prefrontal cortex and hippocampus, scientists have observed alterations in dendrites, the branched extensions of nerve cells that receive signals from other neurons. With increasing age, dendrites shrink, their branches become less complex, and they lose dendritic spines, the tiny protuberances that receive chemical signals. In a study of rhesus monkeys, scientists found the aging process targets a certain class of spines called thin spines.

This has led scientists to speculate that thin spines might be involved in working memory, which requires a high degree of synaptic plasticity. The loss of thin dendritic spines could impair neuronal communication and contribute to cognitive decline.

Finally, the formation of new neurons — a process called neurogenesis — also declines with age. Although scientists once thought neurogenesis came to a halt after birth, we now know that two brain regions continue to add new neurons throughout life: the olfactory bulbs and the dentate gyrus of the hippocampus.

But the jury is still out on these findings — in a study , researchers failed to find any evidence of new neurons in adult brains. Still, studies in mice have found that strategies to boost neurogenesis, such as regular exercise, can improve cognitive function. As we age, our brains may also generate fewer chemical messengers. Several studies have reported that older brains synthesize less dopamine, and there are fewer receptors to bind the neurotransmitter.

One study found and year-olds with mild cognitive impairment had less serotonin in their brains, and the researchers wondered whether manipulating serotonin levels might help prevent and treat memory loss. Our brains undergo myriad changes during the aging process. However, scientists are learning every day how adopting a healthy lifestyle can delay or minimize the negative consequences of these changes.

This article was adapted from the 8 th edition of Brain Facts by Deborah Halber. Alexis Wnuk Alexis is the science writer and editor for BrainFacts. She graduated from the University of Pittsburgh in with degrees in neuroscience and English.

Bender, A. Differential aging of cerebral white matter in middle-aged and older adults: A seven-year follow-up. NeuroImage , , 74— Burke, S.