Key takeaways:
The major structures and pathways of the brain are in place when a baby is born.
Some important parts of the brain aren’t fully developed until your mid-20s.
Learning is a lifelong process. Good physical and mental health can help you preserve your brain function.
Has a toddler ever amazed you with their ability to see a tiny object? Then, shocked you when they push it up their nose? Maybe, you’ve marveled at a teen’s capacity to solve complex equations, but the next choice they make seems impulsive or illogical. Isn’t it strange how you remember song lyrics from decades ago, but always lose your keys?
Your brain’s 100 billion nerve cells are a wonder and a mystery. And they’re always changing as you grow. But is there a time in life when your brain is fully developed? Read on to learn more about how your brain develops and the things that can affect it.
How does the brain develop as we grow?
Kids grow up fast. So do their brains. A child’s brain grows rapidly between birth and the age of 6, when it’s about 90% of adult size. The main nerve pathways are in place by the age of 2. And your brain is its largest between the ages of 11 and 14.
But size isn’t everything! There’s a lot of fine-tuning that happens after your brain stops growing. This even means that some brain cells die so that others can be more efficient. And your genes and the environment around you both play a role in how your brain develops.
The brain has many different functions. But they don’t all develop at the same rate. For example, the way your brain takes in messages from your senses is well developed by the age of 5. But changes happen in the way you process emotions, make decisions, and remember things throughout your childhood and beyond.
Is a baby’s brain developed when they’re born?
Nerve pathways in the brain begin to form 3 weeks after conception. Nerve cells, also called neurons, move or migrate to different parts of the brain where they start to perform various functions. For example, some neurons specialize in sending signals for movement. Others process information from the senses.
Myelination also begins before birth. Myelin is insulation that forms around parts of the nerve cell. Neurons need this myelin to send and receive messages. A newborn has more myelin around sensory nerves than around motor nerves. Myelination continues for cells in different parts of the brain until early adulthood.
Synapses also start to form before a baby is born. These are connections between nerve cells. Even before birth, an unborn baby gets messages from the environment and starts to move. This creates more synapses for neurons to communicate with each other.
Most of the major nerve pathways are in place when a baby is born. But they continue to develop in the first few years of life — and even for decades after that.
At what age does the brain stop developing?
When it comes to the brain, development doesn’t always mean growth. Some neurons die or get pruned early in life so that others can function better. The remaining neurons start to connect and send signals to each other. These are all important parts of brain development.
The last part of the brain to mature is the part that makes us human: the prefrontal cortex. It controls complex thinking, decision-making, impulse control, and personality. The neurons in the prefrontal cortex are present at birth, but they aren’t fully myelinated and connected until around the age of 25.
What types of things affect brain development?
Your genes play a role in brain development. Some important factors before birth and in the first years of life can affect brain development. These include:
Sensory experiences and motor activities
Exposure to certain drugs and medications
The influence of sex hormones
The quality of relationships with parents and caregivers
The quality of relationships with peers
Significant stresses early in life
Diet and nutrition
The microbiome (bacteria that live in the intestines)
But even after childhood, our health habits and environment play a role in brain health. Neuroplasticity means that nerve cells can respond to factors inside or outside of the body. These changes can be positive and lead to new learning and a slower fall in function. Or they can be negative changes with neurons no longer working as they should.
What effect do drugs have on the brain if it’s not mature?
A psychoactive substance is a drug or medication that affects how the brain works. The developing brain is especially sensitive to the effects of these substances. That includes some prescription medications and recreational or illegal drugs. Exposure before birth or early in life can affect brain development.
The greatest risk of developing a substance use disorder is during adolescence. This is the time of life when the prefrontal cortex is still maturing. Early exposure to cannabis (marijuana) can impair memory, attention, and the ability to learn. In rare cases, it may cause psychosis (losing touch with reality) in teens and young adults. And alcohol at a young age can lead to a loss of brain cells, impulsive behavior, and learning challenges.
At what age does brain function decline?
The size of your brain starts to shrink in your 30s and 40s. This increases even more around the age of 60. Sometimes, this makes it harder to remember names or words, do more than one thing at a time, or focus. These age-related changes are different from dementia. Dementia causes changes in the brain that affect a person’s ability to take care of themselves.
But there is good news when it comes to the aging brain. Some things that can help to preserve and boost brain function as we get older include:
Trying new activities that challenge your brain
Getting enough physical exercise
Eating an anti-inflammatory diet
Having loving and supportive people in your life
Cultivating a healthy perception of the world
Getting enough sleep
Can dietary supplements help with brain health and development?
The brain needs nutrients for its health and development. But, there is no good evidence that taking supplements is good for brain health. Getting these nutrients through your diet is more effective. The MIND diet helps to preserve brain function in older adults. It emphasizes:
Vegetables
Berries
Nuts
Beans
Whole grains
Chicken
Fish
Olive oil
That also means, of course, avoiding processed foods, sugar, and too much red meat and dairy.
The bottom line
One of the biggest challenges for the human brain is to understand itself. We are always learning more about how the brain develops, functions, and adapts. In fact, most of the building blocks of the nervous system are in place when we’re born. But some important structures and pathways aren’t mature until we’re about 25 years old. Even after that, we continue to learn, grow, and change. Through good physical and emotional health, you can help preserve your brain function for years to come.
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