What happens to our brain as we age

In some degree, brain aging is unavoidable, but not uniform; it affects all, or every brain, differently. The perfect elixir for attaining everlasting youth will be to slow down brain aging or stop it entirely. Is brain growth a slippery slope we have to take on? Or should we take action to bring down the rate of decline?

Brain aging
Brain ageing is felt differently by all. The rate of cognitive impairment has more effect on some people than others.

The human brain is a staggering engineering feat of around 100 billion neurons interconnected through trillions of synapses at about 3 pounds in weight.

Our brain develops more than any other part of our body in our entire lifespan. From the moment the brain starts to grow into old age in the third week of gestation its complex structures and roles are evolving, linking and severing networks and pathways.

A child’s brain develops more than 1 million new neural connections every second during the first few years of life. Brain size grows fourfold in the childhood period and hits around 90 percent of adult volume by age 6.

The frontal lobes – the brain region that is responsible for executive functions such as planning, working memory, and impulse control – are among the last areas of the brain to mature, and they may not be completely formed before age 35.

Normal brain aging

As we age, all of our body systems are deteriorating slowly-including the brain. “Brain drops” are synonymous with aging. In their twenties, people sometimes suffered the same minor memory lapses, and still did not give it a second thought.

An old man smiling
Having slight memory slips is normal in both younger and older people.

Older people also become nervous about slips of memory because of the connection between memory loss and Alzheimer’s disease. Alzheimer’s and other dementias, however, are not part of the aging cycle.

Changes to traditional memory correlated with natural ageing include:

  • Difficulty learning something new: Committing new information to memory can take longer.
  • Multitasking: Slowed processing can make processing and planning parallel tasks more difficult.
  • Recalling names and numbers: Strategic memory that helps memory of names and numbers begins to decline at age 20.
  • Remembering appointments: Without cues to recall the information, appointments can be put safely in storage and then not accessed unless the memory is jogged.

Although some studies indicate that one-third of older people struggle with declarative memory (memories of facts or events that have been preserved and can be retrieved), other studies show that one-fifth of 70-year-olds perform cognitive tasks as well as their counterparts of 20 years of age.

Scientists are currently collecting parts of the big brain science puzzle to decide how the brain shifts slowly over time to cause those shifts.

General changes predicted to occur during brain ageing include:

  • Brain mass: Shrinkage in the frontal lobe and hippocampus – areas involved in higher cognitive function and encoding new memories – starting around the age of 60 or 70 years.
  • Cortical density: Thinning of the outer-ridged surface of the brain due to declining synaptic connections. Fewer connections may contribute to slower cognitive processing.
  • White matter: White matter consists of myelinated nerve fibers that are bundled into tracts and carry nerve signals between brains cells. Myelin is thought to shrink with age, and as a result, slow processing and reduce cognitive function.
  • Neurotransmitter systems: Researchers suggest that the brain generates less chemical messengers with aging, and it is this decrease in dopamine, acetylcholine, serotonin, and norepinephrine activity that may play a role in declining cognition and memory and increased depression.

In understanding the cognitive impairment neural basis, researchers will discover which treatments or techniques will help delay or avoid brain degradation.

Recent discoveries in brain aging

Several brain experiments are underway to address the conundrum of brain ageing, and numerous discoveries are made.

Stem cells

Recently, researchers from New York’s Albert Einstein College of Medicine discovered in a mouse test that stem cells in the hypothalamus of the brain are likely to regulate how quickly ageing happens in the organism.

“Our work shows that the amount of hypothalamic neural stem cells gradually decreases throughout the animal’s life, and this decrease accelerates aging,” says Dr. Dongsheng Cai, Ph.D., professor of molecular pharmacology at Einstein. “But we also consider the consequences of the loss not to be permanent. By replenishing these stem cells or the molecules they create, different aspects of ageing can be slowed down and even reversed in the body.

Injecting hypothalamic stem cells into the brains of regular old mice and middle-aged mice, whose aging steps had been killed, delayed or reversed. The researchers suggest that this is a first step towards reducing the aging process and age-related diseases potentially treated.

SuperAgers

“SuperAgers” are a special category of over 80-year-old individuals who have memories as vivid as decades younger healthy people.

Studies by the Feinberg School of Medicine at Northwestern University in Chicago, IL, contrasted SuperAgers to a control group of the same-age individuals. Researchers found that SuperAgers ‘brains shrink at a slower pace than their age-matched counterparts, resulting in greater resistance to the usual memory loss observed with age, thereby revealing that cognitive impairment associated with age is not unavoidable.

“We find that SuperAgers are immune to the usual rate of deterioration we see in ordinary elderly people, and they continue to strike a balance between life span and health status, living very well and enjoying their later years of life,” says Emily Rogalski, associate professor at the Cognitive Neurology and Alzheimer’s Disease Center (CNADC) at the Feinberg School of Medicine at the Northwestern University.

Through researching how special SuperAgers are, the researchers aim to uncover biological factors that can lead to the advanced age survival of memory capacity.

Therapies to help slow brain aging

Factors that speed up brain deterioration have been identified. For example, midlife obesity may accelerate brain aging by about 10 years, and soda varieties of both sugar and diet are associated with fast-tracking brain age, having smaller overall brain volume, worse episodic memory, and a shrunken hippocampus.

Old man and woman ridding
Engaging in regular exercise may help prevent cognitive and memory decline.

A growing body of evidence suggests that people who experience the least declines in cognition and memory all share certain characteristics:

  • partaking in regular physical activity
  • pursuing intellectually stimulating activities
  • staying socially active
  • managing stress
  • eating healthily
  • sleeping well

Recent work illustrates a multitude of ways in which we can take active responsibility for our wellbeing and even decrease the age of our brains.

Exercise

One method that regularly comes up to stave off age-related mental deterioration is exercise.

A combination of aerobic and moderate-intensity resistance exercise for at least 45 minutes per session and on as many days of the week as possible has been reported to substantially improve brain capacity in people aged 50 and over.

Similarly, other studies conducted by the University of Miami showed that individuals over the age of 50 who were involved in little or no exercise reported a loss in memory and reasoning skills equivalent or 10 years of aging in 5 years relative to those who took part in moderate or high-intensity exercise.

Dancing has also shown to have an anti-aging impact on seniors ‘brains. A study conducted by the German Center for Neurodegenerative Diseases, Magdeburg, Germany, found that although routine exercise may reverse signs of brain ageing, the most profound effect was seen in dancing individuals.

Playing an instrument

In Toronto, Canada, Baycrest Health Sciences disclosed why playing a musical instrument can help older adults prevent age-related cognitive declines and maintain their listening skills.

Studies found that learning to play a sound on a musical instrument affects brain waves in such a way as to enhance the listening and hearing ability of an person. The change in brain function suggests that the brain rewires itself to prepare for illness or injury that may prevent a person from performing tasks.

“It was proposed that the act of playing music involves multiple brain systems to function together, such as vision, motor and perception systems,” Dr. Bernhard Ross, senior scientist at the Rotman Research Institute in Baycrest said. “This study was the first time we saw clear brain changes after one session, showing that the process of music development contributes to a rapid shift in brain function.”

Diet

Diet is a main constituent of brain health. Recent research has linked healthy brain aging with omega-3 and omega-6 fatty acids in the blood. However, another study showed that eating foods included in the Mediterranean or MIND diet is correlated with a lower risk of memory disorders in older adults.

Study by the University of Illinois, Champaign, IL, showed that middle-aged individuals with higher levels of lutein – a nutrient showed in green leafy vegetables such as kale and spinach, and eggs and avocados – had identical neural responses to younger people than those of the same generation.

“As people get older, they are undergoing a normal decay. Research has however shown that this process can begin earlier than anticipated. You may also begin to see some differences in the 30s, “tells the study’s first reviewer, Anne Walk, a postdoctoral scholar. “We want to understand how diet has a lifelong effect on cognition. If lutein will protect from decline, we can urge people to consume lutein-rich food at a point in their lives when it has the most value.

American adults over 65 are expected to more than double in 40 years, rising from 40.2 million in 2010 to 88.7 million by 2050. Because of this aging population, recognizing the cognitive changes that go hand in hand with ageing will become increasingly relevant.

While many questions remain about the aging brain, work is making strides in highlighting what happens during our lifespan to our cognitive functions and memory, and it emphasizes ways in which we can maintain our mental abilities to improve our quality of life as we transition into older adulthood.

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