Brain Plasticity: What is it and How Does it Relate to Autism, Alzheimer's, and Normal Learning
I was doing some research on human development and came across a book that had my jaw agape. Excited by what I read, I wondered why I hadn’t learned this in college. It’s astounding, life-changing…brain altering. Literally.
The evidence and research I read was connected to so many current cognitive issues we see today. Autism, speech disabilities, Alzheimer’s….It was intriguing to read how the brain experienced life upon birth and how that experience can impact a person for life.
It’s not just one part of the brain, it’s how the brain reacts and changes to the information it receives through human experience.
Now these issues aren’t necessarily reversible as we may refer to them, but they are not permanent. They aren’t ‘unchangeable’. And some can be avoided later in life by understanding our brains.
The brain that drives us…right?
Actually, we drive it.
Before we get to that, let’s talk about how the brain functions, how it maps itself and ultimately how we are ‘injuring’ it.
We’ll cover what we can do differently to prevent it, and what can be done to improve current cognitive disabilities.
So let’s go to the beginning: ours. It all starts with infancy.
As we are forming in the womb our brains develop. The brain consists of neurons that process information through electrochemical signals. Through sensory experience, pulses are received in neurons, they travel along the axon of neurons, and jump through a path called the synapses to other neurons.
Inside the axon of neurons are neurotransmitters which are chemical messengers. Thus, the electrochemical signal referenced before.
These neurotransmitters relay, modulate or amplify signals and upon binding to other neuron synapses cause a change. This change is either the excitement of a neuron or the inhibition of it which causes another reaction.
So, what does this mean and how does it relate to our cognition?
It’s the foundation upon which this discovery is built. It is how brains map themselves .
Think about the pathways neurons travel like a person walking through a field. We walk, knock high grass down, and eventually there is a path.
When neurons respond to stimuli they make a path they can use again. That way it’s easier the next time. And there we have a very crude description of brain mapping. (Because it’s really a lot more beautiful than a field!)
I promise it won’t get much more complicated than what we just covered. My intention was to give you a picture of the brain so you can understand how incredible this neuroscientist’s discovery was.
So let’s get to it.
The Critical Period
During infancy there is a period referred to as the ‘critical period’.
Researchers Hubel and Wiesel found during an experimentation that between three and eight weeks an infant must receive visual stimulation in order for the brain to develop normally .
In other words, during that time, infant brains are testing out and setting the stage for brain processing and mapping in response to neural stimuli. Their brain learns how it will continue to process information based on the information it receives. The brain establishes its paths in open fields….
Think of it like this, it’s your first day on the job, how you are taught the basic functions of that job is how you will carry it out forever. But there is a catch: if your trainer misses teaching you any fundamental part, you will never be able to perform that function –ever.
That is what Hubel and Wiesel discovered. In fact, their experiment involved sewing a kitten’s eye shut during that critical stage ( I know, so sad, don’t get me started), the brain area controlling sight for that eye did not develop at all, and the kitten became blind in that eye .
But what they found after that, was the area of the brain that controlled the other eye actually moved into that part of the brain that the blind eye previously had. The brain literally rewired itself and took over the brain map allocation for the other eye .
So how does this translate? Use it or lose it...right? If your brain gets the proper stimuli, it maps. If not, that map space goes dark...but...
Recall how the brain adapted in response to the loss of sight. It literally rewired and changed itself based on the experiences of the kitten.
This is referred to as brain plasticity.
During infancy and childhood, brains that receive the appropriate visual stimulation required for normal development continue to connect firing neurons with each other through repetitive actions and learning—thus they take up real estate in the brain ‘map’ so that that information is well organized, protected, and retained . (The path in the field)
Recall that the theory was brain plasticity comes to a screeching halt after childhood.
Boy were they wrong.
It was known from the 1930s and through the research of Penfield that brains were ‘mapped’ topographically in relation to their corresponding body parts .
So, all five fingers on your hand are also represented in the same positions in the brain. The middle finger sensory receptors lie between the index and ring fingers and so on.
It is mapped in that way through sensory exposure –the brain receives signals from your body parts and maps them as they are aligned.
This makes processing information more efficient. Smart brain, huh? The brain knows if it maps together the parts of the body that are used together, it will work quickly so you can function efficiently.
Plasticity. Ooooh, say it again.
The brain remains plastic throughout childhood- it is able to change its mapping to accommodate learning and wire itself through experience. But as youth fades, it was thought the same for plasticity.
Localizationists vehemently believed that the dynamic nature of the human brain stops after puberty. It would be rigid and unchanging.
In other words the they claimed the brain can’t change after that point- it cannot be remapped, it cannot learn the way it did before and it’s not as fast or efficient.
Neuroscientist and innovator Merzenich proved that the brain continues to dynamically change and rewire itself after puberty and throughout adulthood .
Merzenich conducted research that would change the way we know brains, and learn.
He found repetitive behavior caused a relationship between neurons. When the brain realized certain neurons often fire together, the neurons essentially bonded so they could be tapped into simultaneously while performing a task.This results in the brain requiring less resources to carry out a task by having fused neurons, and thus becoming efficient . In other words, neurons that fire together, wire together .
What does this mean, exactly?
Well, think about the phrase ‘practice makes perfect’. The brain takes that phrase 'literally' when applied plasticity.
It happens like this: when you first learn a skill, you clumsily attempt to perform what you are being shown. Your thoughts cover every aspect as you carefully carry out your task. However, as you repeatedly engage in what you were taught, your brain starts realizing ‘hey, when she does this, we use all of these neurons at the same time, so let’s just get them together for the next time so it’s easier”. Neurons that fire together, wire together.
Thus, as you learn the piano, karate, to drive…. these tasks become ‘second nature’ because your brain made it so. Thanks, Brain!
It rewires itself so you use less resources to perform. The brain map itself takes up more space as you learn these skills. It literally gets bigger because that task is what you focused and perfected upon.
But that’s not the only fascinating part: the brain also rewires itself when it experiences loss or change.
For instance, if you lose a finger, your brain will rewire itself to ignore the finger and allow that space to be used by adjacent brain maps . Or if you have a finger reattached and somehow the surgery results in crossed nerves, your brain will ‘rewire’ itself to understand the new signals, remap to normalcy, and allow you to function normally . Thanks again, Brain!
It’s a fully adaptive living organ that can understand and process changes; as a result it changes itself! It applies these same principles in training and learning a new skill. The brain determines which neurons you’re summoning, wires together the ones which fire together, and remaps your brain to permit that space to be devoted to your new talent. But, you hear it all the time “pay attention” and pay attention you must…especially after the critical stage.
Merzenich found during research with adult monkeys that the brain remapping for the learned skills only lasted when monkeys were fully engaged and completely attentive during learning. Now listen, this goes deeper than just ‘paying attention’. This subtle piece of observed data led Merzenich to a completely mind blowing discovery.
We know it involves paying attention to procure lasting changes.
Well, are you?
Gooood. You will need to for this next part.
So how does concentration affect the way the brain processes information and maps itself?
BDNF It's the key
Well, quickly I’m going to go back into some technical terms, but stay with me here, this is where Autism, Dementia, and other disorders come into play.
During childhood, the part of the brain that permits intense concentration and attention is turned on known as the nucleus basalis . It is only turned on during the critical learning window as a child which, if you recall, is between three and eight weeks . What that means is whatever we learn during that critical phase and how we process it is locked down- it is the ‘bronzed’ path in the field.
It seems like such a small amount of time for an infant’s brain to master processing information correctly, doesn’t it? How in the world can it build a foundation of what it needs to know in order to function normally in a mere five weeks? That’s the exciting part.
Who am I kidding? They are all exciting parts! Let’s just keep this crescendo of excitement going.
Merzenich found that during this critical phase a nerve growth factor called brain derived neurotrophic factor (BDNF) is released. So while all this new stimuli is awakening new neurons and creating pathways, BDNF reinforces those plastic changes. It’s the control system of plasticity . BDNF also turns ON the nucleus basalis---the part of our brain that controls focus and attention on a task.
The nucleus basalis is kept on the entire time during the critical stage.
You know some call children 'little sponges' for how well they absorb information? Babies during the critical stage epitomize a sponge. They literally absorb everything- thanks to the BDNF opening up the nucleus basalis. It creates effortless learning by focusing attention on whatever is being experienced, absorbed, and learned.
Once key connectors and pathways are established, BDNF shuts the door to the nucleus basalis and then we have to really start ‘trying’ to learn. Thanks….Brain.
So these new kids got a crash course on life, and their brain maps are ready to efficiently interpret stimuli and produce responses.
That’s how it works for those who were not predisposed to Autism, or had some other speech or learning disability.
If you’re guessing that BDNF and brain mapping has something to do with not learning correctly, you have used your brain wisely.
Let’s talk about the BDNF and how it relates to Autism and other disabilities.
We talked about the critical stage and how it works for children without predispositions to learning disabilities, however; Merzenich took a closer look at BDNF. He devised a theory about its connection to Autism. He performed research on rats with the same autistic brain mapping.
When the rats were exposed to white noise, (noise that had indistinguishable notes or loud continuous tones) during the critical stage of brain development, all of their neurons became overexcited.
Normal brains would have certain pathways of neurons light up in response as it processed the noise. But the Autistic rats responded with their entire brain. All neurons were on fire.
So what does this mean?
Recall the phase where BDNF reinforces important information and solidifies pathways in normal brains—well, that is a really important part. It did not happen for the rats with the autistic brains. Instead, BDNF was dumped over the entire brain.
So now imagine the grass field we were making pathways in earlier? Now it’s all completely flattened. Now there are no identifiable paths to take.
After the release, BDNF thinks ‘my job is done’ and shuts down the nucleus basalis prematurely. This prevents future normalized learning and brain mapping. All brain areas are left undifferentiated.
The results? Abnormal sound and sensory processing.
So how do rats exposed to white noise relate to Autistic children?
Merzenich connected the rat research to humans by researching children with Autism.
Many of them had the same atmosphere that the rats did: white noise. They lived in extremely loud environments such as by highways or airports. These loud noises caused adverse impacts of exciting all neurons during the critical stage which resulted in a premature release of BDNF.
This fired up their whole brains and sealed in the flattened fields. Thus, their brains respond to sensory stimuli with everything at one time.
It's important to note these children were already genetically predisposed to autism, so don't get loud noises confused with the 'cause' of autism. It's not.
This brings us full circle to the ongoing brain obstacles children with Autism have: since the nucleus basalis shut down prematurely during the critical stage, the abnormal pathways are sealed and future effortless learning cannot take place.
Well, you know that can’t be true, right? Why else would I be so excited?
Because there are solutions, thanks to Merzenich.
Merzenich took those rats with the Autistic brains and exposed them to repeated isolated tones. Through this repetition and isolation of one tone at a time, the Autistic brains began recognizing and processing one tone at a time and recreating new pathways. The rats’ brains literally remapped themselves toward normalcy .
Read that again; Autistic rats’ brains rewired itself to normalcy after being retrained with single tone exposure.
Through repeated isolation, exposure, and training, the Autistic brains were rewired to normal brain maps.
My mind: blown.
Merzenich took this information and created numerous programs to assist the learning disabled. Not only Autistic children, but those suffering from Dyslexia, deafness, and cognitive issues due to aging. All of them have abnormal brain maps. As a result-- with practice, they can start the rewiring process.
In one case a young girl with Autism and very limited speech practiced two hours per day for eight weeks. After two months, she was able to form full sentences and communicate with her mother .
Studies in 1996 showed learning disabled children in 6-12 week programs improved language skills by 1.8 years. Their tests scores were at, or above, normal. It improved speech skills, math skills, reading skills…. cognitive skills .
This program called Fast ForWord. When I read it and had not heard of it, I was shocked. Why isn't this information plastered everywhere? Well, let me help with that.
If you haven't heard of Merzenich you may have heard of one of his other life-altering inventions.
Merzenich created the cochlear implant. A device that allows deaf people to hear. Its not a hearing aid. This implant is for people who are deaf and their brains cannot process sound at all. So the cochlear implant is a tiny machine that translates sound into electrical signals that the brain can actually process.
This guy is kinda my hero.
Now if you have a child with a learning disability, check this entire book out for free here. It’s called “The Brain that Changes Itself” by Dr. Norman Doidge.
You’ll find a wealth of information regarding all the research and discoveries discussed here.
You can also check out Dr. Merzenich’s program here.
Improve Your Plasticity
For those not facing disabilities, we can also continue to change our brains.
However; since the BDNF shut off access to the nucleus basalis, recall we have to find other portals to retaining and reshaping our brains.
We must expend more effort in concentrating and paying attention to rewire our brains to learn efficiently while also not losing what we have learned.
Merzenich’s studies showed if we do not use learned skills, eventually our brain map space for that skill will be taken over by some other practiced skill .
Lumosity and other are designed to keep brains sharp. Merzenich also has daily brain training brain games here.
But don’t just rely on these designed games. Do what you’re doing now: learn new things every day.
It’s the lack of INTENSIVE reading and brain use that results in the loss of brain maps and brain power.
Merzenich showed you have to pay attention, put forth effort and be consistent. Remember, you’re showing your brain new paths to make. It takes time, especially as we get older.
Commit to exercising your brain like a muscle. Inactivity has the same effect as not exercising your bodies; muscles atrophy. As does your brain. Which was another interesting study Merzenich reviewed.
Retain Plasticity While Aging
Merzenich connects neglect of intensive reading and learning to Alzheimer’s and Dementia .
As we age, the brain processes things more slowly because we use it less. As we age, we get comfortable, we stop going to school, we’re set in our careers and our brain goes into this couch potato mode.
Combine that with simple aging and we have a brain that is slowly losing its ‘muscle tone’. Alzheimer’s and dementia can be the ultimate result.
And drugs aren’t always the answer.
Exercise is. Mental exercise.
Merzenich’s studies showed with intense training of 40-50 hours over a few weeks, elderly subjects with memory issues improved their brain mapping by up to 30 years! .
This training improved language, memory, speed, and fine motor skills in his subjects. Human subjects! Seriously, it’s simple: use it or lose it.
The Amazing Dr. Merzenich
Clearly the human brain is an amazing thing--and Merzenich’s brilliant brain has exposed just how phenomenally resilient our brains really are.
All we need is a little understanding how they work, dedication to force remapping, and attention.
Seriously, put your smart phones down and pay attention! Stop losing plasticity by simply paying attention.
Finally, treat your brain like a muscle, exercise it often and keep feeding it.
Dr. Merzenich, if I should ever be so lucky that you stop by and read this article, I hope you grasp through my excitement how much I admire you and your discoveries.
Seriously, send me a map of your brain so I can remap mine like yours!
So, friends-what do you think? Do you have a child suffering from cognitive issues?
Have you tried these techniques to help your child remap their brains?
If not, tell us what you have tried that has succeeded or failed?
 Doidge, N. (2007). The Brain That Changes Itself. New York: Viking.