Neuroplasticity facts for kids

Kids Encyclopedia Facts

Neuroplasticity, also known as brain plasticity, is the amazing ability of your brain to change and reorganize itself. Think of your brain as a super flexible network! It can rewire itself to work differently than before. These changes can be small, like individual brain cells making new connections, or bigger, like entire parts of the brain changing their jobs.

Your brain changes when you learn new things, when your environment is different, when you practice a skill, or even when you feel stressed. For a long time, scientists thought this only happened when you were a kid. But now we know that your brain can keep changing, or be "plastic," even when you're an adult! However, a younger brain is even more flexible than an adult brain. This ability to change is super important for healthy development, learning, remembering, and recovering from brain injuries.

History of Brain Plasticity

How the Idea Started

The idea of "plasticity" was first used for behavior in 1890 by William James. He wrote about it in his book The Principles of Psychology. The term "neural plasticity" (meaning brain plasticity) was first used by a Polish scientist named Jerzy Konorski.

One of the first clues about brain plasticity came from an Italian scientist, Michele Vicenzo Malacarne, way back in 1793. He trained some animals for years and then looked at their brains. He found that the trained animals had bigger cerebellums (a part of the brain) than the untrained ones. This was a big discovery, but people forgot about it for a while.

Even after William James talked about the brain not being fixed, many scientists still believed that the brain's structure was set in stone once you became an adult. But in the early 1900s, Santiago Ramón y Cajal, often called the "father of neuroscience," used the term "neuronal plasticity." He used it to describe how adult brains could change, even without injury. He showed that brain cells (neurons) are the basic units of the nervous system. This idea helped scientists understand how the brain could change.

Discoveries and Research

In 1923, Karl Lashley did experiments with monkeys that showed changes in brain pathways. This was more proof of plasticity. But still, many scientists didn't fully accept the idea.

In the 1960s, Marian Diamond from the University of California, Berkeley, provided the first clear scientific proof that the brain's structure could change. She published her research in 1964.

Other important discoveries came from scientists like Paul Bach-y-Rita and Michael Merzenich.

In the 1960s, Paul Bach-y-Rita invented a device that helped people "see" using vibrations on their skin. This showed how the brain could adapt and use new ways to get information.
Scientists also saw brain plasticity in people recovering from stroke. Healthy parts of the brain could sometimes take over jobs from damaged parts.
Eleanor Maguire studied London taxi drivers. She found that their hippocampi (a brain area for memory) changed as they learned the city's complex layout. This showed how learning can change brain structure.

Michael Merzenich has been a leader in neuroplasticity research for over 30 years. He was inspired by a discovery from David Hubel and Torsten Wiesel. They found that if one eye of a kitten was closed, the part of the brain that usually processed information from that eye didn't just sit there. Instead, it started processing information from the open eye! This showed that the brain didn't want to waste any "space" and could rewire itself.

This suggested brain plasticity during a "critical period" (an early time in life). But Merzenich argued that plasticity could happen even in adults. He saw this when studying monkeys whose nerves were cut and then reconnected. The brain maps for their hands, which should have been messy, became almost normal again. This was a huge step, proving that the brain is truly plastic.

How Brain Plasticity Works

The core idea of neuroplasticity is about how connections between brain cells (called synapses) change. These changes happen through different pathways. These pathways allow for changes in how genes work, which then leads to changes in brain cells and, finally, to neuroplasticity.

Other things also play a role in how brain networks change. These include how synapses are controlled, the role of inflammation, certain proteins, and how the brain produces energy.

Types of Brain Plasticity

Scientists often talk about two main types of neuroplasticity:

Structural neuroplasticity
Functional neuroplasticity

Structural Neuroplasticity

Structural plasticity is when your brain changes its actual connections between neurons. New neurons are always being made and added to your brain throughout your life. Scientists use special scans like magnetic resonance imaging (MRI) to see these changes. This type of plasticity looks at how different things, like learning or experiences, change the brain's physical structure. For example, changes in the amount of grey matter (brain tissue) or the strength of connections between synapses are examples of structural plasticity.

Functional Neuroplasticity

Functional plasticity is when your brain changes how its neurons work. These changes can happen because of past activity, like when you learn something new and form a memory. Or they can happen after an injury, where one part of the brain takes over the job of a damaged part to help you recover.

When synapses get stronger or weaker, it changes how often neurons "fire." This is called synaptic plasticity. For example, long-term potentiation (LTP) makes synapses stronger, and long-term depression (LTD) makes them weaker. Both are linked to memory. The cerebellum, a part of your brain, is a great example of where LTP and LTD work together.

What Brain Plasticity Helps With

Your adult brain isn't "hard-wired" like a machine. It can change its connections in response to learning, training, and even injuries. New brain cells can even be born in adults, especially in areas like the hippocampus (important for memory).

This ability of the brain to change is why we can learn and remember. It's also the basis for many theories about how the brain works.

Recovering from Brain Damage

One amazing thing about neuroplasticity is that if one part of the brain is damaged, another part can sometimes take over its job. This is super important for people recovering from brain injuries. Neuroplasticity is the main reason why therapies like physical therapy can help people get better after a stroke.

Some therapies that use brain plasticity to help recovery include:

Constraint-induced movement therapy: This encourages using a weaker limb by restricting the stronger one.
Functional electrical stimulation: Using electricity to help muscles move.
Treadmill training with body-weight support.
Virtual reality therapy: Using virtual worlds for rehabilitation.

Scientists have also studied if the hormone progesterone could help people with brain injuries. While early studies in animals looked promising, bigger studies in humans found that progesterone did not significantly help patients with severe brain injuries.

Seeing with Both Eyes

For a long time, people thought that if you didn't develop binocular vision (using both eyes together for depth perception) as a young child, you never would. But now, we know that people with certain eye problems can improve their vision later in life. This is a great example of neuroplasticity at work!

Phantom Limbs

A diagram showing how a mirror box works. It helps people with phantom limb pain by making them see a reflection of their good hand where their missing limb would be.

Sometimes, after a person has an amputation, they still feel pain or sensations in the missing body part. This is called a phantom limb. It happens to many amputees. One idea is that the brain maps for the removed limb get "taken over" by nearby brain areas. So, when those nearby areas are active, the brain misinterprets it as coming from the missing limb.

Scientists like V.S. Ramachandran and Herta Flor have studied this. Flor found that brain changes (cortical remapping) happen mainly in patients who feel phantom pain. This is sometimes called "maladaptive plasticity" because the brain's changes cause problems.

In 2009, Lorimer Moseley and Peter Brugger did a study where they asked arm amputees to imagine moving their phantom limbs in "impossible" ways. Some succeeded! This suggests that their brains actually changed the mental picture of their bodies, showing how powerful the brain's ability to change itself is.

Long-lasting Pain

People with chronic pain feel pain for a long time, even after an injury has healed. This is also linked to neuroplasticity. When you have an injury, pain signals go to your brain. If this goes on for a long time, your nervous system can reorganize itself. The brain's "map" for the painful area can change, making it more sensitive to pain. For example, people with certain pain conditions might have less grey matter in parts of their brain. But after treatment, these brain changes and symptoms can get better.

Meditation

Studies have shown that practicing meditation can actually change the thickness or density of gray matter in your brain. Sara Lazar and Richard Davidson have done famous studies on this. Their research suggests that meditation can change brain areas linked to attention, anxiety, depression, fear, anger, and even the body's ability to heal.

Fitness and Exercise

Being active and exercising is great for your brain!

Aerobic exercise (like running or swimming) helps new brain cells grow, especially in the hippocampus, which improves your memory.
Regular exercise over several months can significantly improve your executive functions (how you plan, focus, and control your behavior).
It also increases the volume of gray matter in many brain regions, especially those important for thinking and control, like the prefrontal cortex and hippocampus.
People who are more physically fit often have better executive function and larger brain volumes in key areas.

Deafness and Hearing Loss

When people lose their hearing, their brains adapt. The auditory cortex, which usually processes sounds, starts to be used for other senses, especially vision and touch.

Deaf individuals often have better peripheral vision, are better at detecting motion, and are faster at visual tasks compared to hearing people.
Brain areas that usually handle sound might start processing touch information in people who are born deaf. They might be more sensitive to vibrations.

Cochlear Implants

Neuroplasticity is key to how our senses develop. A baby's brain is not fully developed at birth and learns from sensory inputs. For children born with hearing loss, cochlear implants (devices that help with hearing) can activate the auditory system. This helps the brain develop hearing abilities. There's a "sensitive period" (usually the first 2-4 years of life) when this intervention is most effective. If children get cochlear implants early, they can often learn to speak and communicate well.

Blindness

When people lose their vision, their visual cortex (the part of the brain for sight) can also change. It might start processing information from other senses, making them stronger. For example, some studies show that parts of the brain linked to vision become more active in blind people during sound-based tasks.

Human Echolocation

Human echolocation is an amazing skill some blind people learn. They make clicking sounds and listen to the echoes to "see" their environment. Studies using brain scans have shown that parts of the brain normally used for vision actually adapt to process these click-echoes! This means the brain rewires itself to use sound for "seeing."

Attention Deficit Hyperactivity Disorder (ADHD)

Studies using magnetic resonance imaging (MRI) show that children and adults with ADHD often have slightly smaller volumes in certain brain areas, like the nucleus accumbens and hippocampus. Their brains also connect differently.

Research suggests that long-term treatment for ADHD, especially with stimulant medications, can help reduce these differences in brain structure and function. It can improve how several parts of the brain work, including areas important for focus and control.

Brain Changes in Animals

Animals also show amazing brain plasticity! Their brains can change throughout their lives due to hormones, evolution, or different life stages. Some changes even happen seasonally.

Seasonal Brain Changes

Many animals change their brains to fit seasonal behaviors, like mating.

Birds: Black-capped chickadees grow a larger hippocampus (for spatial memory) in the fall. Songbirds' brain areas for singing get bigger during mating season.
Amphibians: A part of the amygdala (linked to emotions) in some frogs is larger before breeding and during hibernation.
Mammals: Parts of a female sheep's brain become more receptive to certain hormones during breeding season. Even humans show seasonal changes in a small part of the brain called the suprachiasmatic nucleus.

Research on Brain Injury

Scientists like Randy Nudo and Jon Kaas have studied how animal brains recover from injuries like stroke.

Nudo's group found that if a small stroke happens in a monkey's brain, nearby healthy brain areas can take over the function of the damaged part. This helps scientists understand how to create better treatments for stroke patients.
Kaas studies how the brain's sensory systems respond to injury. He looks at how the brain reorganizes itself after damage.

At Emory University, doctors like Donald Stein studied how progesterone might help with brain injuries. They noticed female mice recovered better from brain injuries than male mice, especially at certain times in their cycle. This suggested progesterone might help. However, as mentioned before, larger human studies found that progesterone did not significantly help people with traumatic brain injuries.

Aging and the Brain

As people get older, especially after age 40 and even more after 70, some genes in the frontal cortex (the front part of your brain) become less active. Many of these genes are important for synaptic plasticity (how connections between brain cells change). This means the brain's ability to change and adapt can decrease with age. There's also more DNA damage in brain cells as we get older.

Learning Multiple Languages

Learning more than one language is really good for your brain! Studies show that people who speak multiple languages often have better thinking skills and are more flexible in their thoughts than people who only speak one language. They might have longer attention spans, better organization skills, and a better understanding of others' thoughts.

Scientists have found that learning multiple languages actually changes the structure of your brain.

One study found that people who speak multiple languages have more grey matter in a brain area called the inferior parietal cortex, which is linked to language learning. People who learned a second language earlier in life had even more grey matter there.
Recent studies also show that learning multiple languages affects the white matter of the brain. White matter helps brain cells communicate. People who actively use two or more languages often have more efficient connections in their white matter.

While scientists are still studying if these brain changes are due to genes or environment, many signs point to the idea that learning languages early in life helps reshape the brain.