Scientists are unlocking the mysteries of the brain and learning more about maintaining brain health. But when it comes to our brains, sometimes it's hard to tell fact from myth.

 

As a neurologist, I’m often asked questions like these about brain health and brain myths.

 

 

Yes, several changes occur in the brain as a result of healthy aging. As we age, our brains normally shrink in size by about 1 to 2 percent every year after age 40. This is due to loss of brain cells and brain cells shrinking in size.

 

Some of our brain functions such as short-term memory, processing speed, attention and the ability to multi-task show some decline with healthy aging. On the other hand, language functions tend to remain well-preserved as we get older.

 

 

This is a very common misperception. There is no scientific basis for the notion that individuals use one hemisphere of the brain more than the other for cognitive functions. Research shows that both hemispheres are required for almost all brain functions.

 

But there are certain brain functions that rely more on one hemisphere than the other in all individuals.

 

Our ability to verbally express ourselves and comprehend language is predominantly controlled by the left hemisphere. Therefore, strokes on the left side of the brain are much more likely to cause language difficulties than right-side strokes.

 

The right hemisphere is important for other aspects of language processing. This includes understanding the emotional intonations of speech, and tuning in to the rhythm and stress of words, which allows us to identify sarcasm and understand the punch line of a joke.

 

 

The brain can adapt to injury such as stroke or head trauma. This process is called brain plasticity.

 

The brain can “rewire” itself so that healthy neurons can form new networks. The brain can also modify existing networks to compensate for the damaged parts of the brain.

 

Synapses are the connections between neurons. They are in a constant state of revision and modification. One of the most important discoveries in the field is that brain activity can stimulate this process. This is called activity-dependent plasticity.

 

Therefore, brain exercises and rehabilitation are crucial in recovery from brain injury. This allows the brain to “re-learn” functions that were lost due to trauma.

 

 

The size of the brain and the number of brain folds on the surface, also known as gyri, are not linked to intelligence or learning new material.

 

We still don't know all the biological processes of intelligence. However, intelligent people probably have better connections between their synapses.

 

In addition, their neurons have stronger networks in certain brain regions that allow the brain cells to communicate with each other more efficiently.

 

There are also some studies that suggest that more intelligent people may have thicker cortices, particularly in some parts of the brain. The cortex is the computational part on the outer surface of the brain, where the majority of the brain cells are.

 

 

The brain goes through many changes starting in the early adolescent years, leading to full maturation by the mid-20s. There is a wide range of variability between individuals regarding when the brain is fully developed. For some that could be as early as age 18 or as late as age 30. But the average is around 25 years of age.

 

This maturation of brain function starts in the back parts of the brain, with the frontal part of the brain, referred to as the prefrontal cortex, being the last to fully mature. This area of the brain is responsible for judgment and problem-solving.

 

It’s also responsible for decision-making, complex planning and organized thinking, along with personality and impulse control. Therefore, these brain functions aren’t fully developed until the mid-20s.

 

The reward centers of the brain are the most active during adolescence. But by the mid-20s, they are back to normal levels of activity. This means that individuals become less sensitive to peer pressure and much better at risk management.