neuroplasticity.
We're diving deep into the nitty gritty of this topic, exploring the
types of neuroplasticity, structural and functional.
It's time to challenge ourselves
In 1970 two scientists from Cambridge University ran an unpleasant and borderline cruel experiment on kittens.
For five months, Colin Blakemore and Grahame Cooper raised kittens in closed-off environments where they could only see horizontal or vertical lines.
They were placed in cylindrical containers with either horizontal or vertical lines on the walls, never both.
When caretakers took them out to feed or handle the kittens, they wore clothing that was covered in either horizontal or vertical lines.
For all intents and purposes, these two groups of kittens experienced different versions of reality.
After being shut into those environments for five months, researchers took them out to see how they’d fare in a world with both horizontal and vertical orientation.
Would their eyes have adapted to their version of reality?
Was there going to be any difference at all?
The kittens, it turned out, couldn’t recognize objects or patterns of the kind that they weren’t exposed to in their sealed-off environment.
The kittens raised in the horizontal chambers could not see vertically-aligned objects; they kept bumping into chair legs and weren’t responsive when researchers thrust a finger toward them in a vertical direction.
Meanwhile, the vertical cats couldn’t find an appropriate place to lie down and take a nap, since they had no ability to recognize horizontal planes.
This surely resulted in some YouTube-worthy videos of kittens being clumsy.
Some of the kittens in the experiment successfully rehabilitated in a few weeks, but many never did.
Their primary visual cortexes had been engineered so strongly in one angle that they were effectively blind to whatever lines they weren’t exposed to during those five months.
This is an example of neuroplasticity that affects the very perception of reality.
Then there is the case of taxi drivers and bus drivers in London.
Researchers from the University of London studied and compared their brain structures in 2000 and discovered something notable: the taxi drivers had measurably larger hippocampi than the bus drivers.
Why might this be?
The theory behind their findings was that taxi drivers had to essentially memorize the entire road map of London—they needed to know the best shortcuts and alternate courses to take, and that required in-depth knowledge about every street and alley in town.
It’s something that could take months or even years.
The bus drivers, on the other hand, only had to drive a couple of pre-planned routes every day with little or no variation.
They only needed to memorize a few turns and perhaps not even the street names.
They could do it through visual memory alone, recognizing buildings or landmarks.
However many people are on the bus makes no difference to the bus driver, as they already know the path and endpoint.
However, being a taxi driver is somewhat like playing Russian Roulette—you never know what you’re going to get or how to get there.
(Okay, maybe that’s more Forrest Gump than Russian Roulette.)
Recall that the hippocampus is directly linked to memory-processing—clearly the taxi drivers memorized more and interacted with their memories more on a daily basis, and thus the hippocampi were larger.
Now, here is an example of neuroplasticity that gets us closer to what we’re looking for.
But don’t forget about the Moken children.
They’re a nomadic tribe who occupy a group of tropical islands in Thailand.
These “sea gypsies” spend the large majority of their lives on boats in the middle of the sea.
They also have the uncanny ability to see extremely well underwater, even at substantial depths—handy when they need to catch fish on a daily basis.
The Moken can do this because they’ve taught themselves how to regulate the shapes of the lenses and pupils of their eyes, as dolphins and seals do.
They were able to constrict those individual eye parts by as much as 22% when underwater.
One might think that trait is just part of the genetic code of the Moken, who have developed it just as Charles Darwin’s finches developed different characteristics as a result of adaptation to different environments.
But that’s because we assume our pupils and lenses just adjust themselves and that it’s an innate act that we can’t control.
This would be proven wrong.
A Swedish researcher tried to train a group of European children how to manipulate their eyes the way the Moken did—and after just 11 sessions in one month, they were able to see underwater just as well as the Moken.
This is an instance of neuroplasticity, as it relates to developing the ability to control your body and kinesthetics.
While we’re at it, let’s talk about musicians.
Researchers found that the brains of professional musicians have a higher volume of gray matter in portions of their brains responsible for auditory processing and motor functions and of course related to musical abilities.
Amateur musicians had slightly less gray matter, and non-musicians had least of all.
For neurological purposes, the greater the amount of gray matter in a certain area, the more developed and robust the underlying ability is.
Just like with the London taxi drivers, repetitive usage and exposure caused specific neuroplasticity.
However, such neuroplasticity is a double-edged sword for musicians.
Among musicians who used two fingers simultaneously to play an instrument (such as a rock bassist), their brains had mapped those two fingers together so that the musician couldn’t move one without moving the other, a phenomenon called focal dystonia.
Remember the homunculus?
Imagine that its two fingers merged into one larger section.
Their brains adapted in such a way that they had to undo that condition through specialized training to play other instruments effectively.
This certainly brings new meaning to why budding musicians are always chided to “practice perfect” or “practice slowly”—because the practice will become embedded in the brain, for better or worse.
Then there are the Russians and linguistic relativity.
A long-standing theory called the Sapir-Whorf hypothesis maintains that our patterns and systems of thought derive heavily from the language we use.
One example of this theory in action is how Russian language speakers define colors in comparison to other tongues.
Whereas Westerners might refer to different shades of blue as “light” and “dark” blue, Russians have two completely different words to distinguish between the two: siniy and goluboy.
That makes Russians slightly faster in discerning the two colors—which they perceive as having completely different names—than other dialects that only see them as alternate shades of the same color.
This demonstrates neuroplasticity as a consequence of simple linguistic changes.
Finally, there’s the elderly.
The common belief is that the brain deteriorates as people age.
But recent research indicates that’s not necessarily the case.
In fact, it’s been found that the brain never ceases making new learning cells and readjusting its neural connections.
Previously, it was believed that the brains of children and young adults conducted neuroplasticity more regularly and that the process slowed down considerably as people got older.
However, researchers found that old people’s brains are just as malleable as those of younger folks—just in a different way.
Old people’s brains develop new “circuits” and different connections to their frontal lobes, which in turn open up new understandings and perceptions that only the rare young adult can develop.
There is, it turns out, a biological basis for the notion of older people being wiser.
What do all these examples prove?
Neuroplasticity isn’t just an unmanageable, innate consequence of what you’re exposed to.
It can be intentionally shaped through several factors like the environment, repeated activities, and linguistics.
And it can, therefore, be trained.
You may not want to possess a map of London in your head, but you can use the same process to learn faster, develop better habits, grow self-discipline, and simply accomplish what you put your mind to.
Neuroplasticity is the vehicle that allows those things.
It simply allows you to translate intention directly to action instead of hoping for the best.
What Is Neuroplasticity?
The above accounts show that neuroplasticity is no joke.
It may have sounded abstract or intangible from the prior chapter, but you can see that there are very real consequences, both negative and positive, from the brain’s tendency to change.
Neuroplasticity is how our brain adapts in ways that reflect our experiences and actions, though not necessarily our intentions.
And we can channel this to improve our lives.
But first, we should distinguish between the two types of neuroplasticity: structural and functional.
Structural neuroplasticity concerns the neuronal connections of the brain and the strength of the neural network.
Structural neuroplasticity takes place by literally changing the brain’s structure to increase the efficacy of a particular set of functions or actions.
It involves building or strengthening the synaptic connections between neurons that you need or want the most and scaling back or removing the ones you don’t.
Our neural networks change according to how regularly we employ them—if we don’t require certain neural pathways in our regular lives, they’re not going to stick around.
In plain English, we create neuroplasticity through repetitive actions and thoughts that eventually become habits, and in doing so we reinforce and improve the function of these neural pathways.
Repeated behaviors create new patterns of thought and habits—little by little, neuroplasticity occurs and starts to wear a groove like a Zen garden or sandbox that gets raked repeatedly so that the grooves become deeper and deeper over time until they are finally unconscious and instinctual.
The brain is always ready to begin this process, because ultimately, these grooves save the brain energy and allow it to do what it wants—habituate and conserve energy.
The London taxi drivers are an illustrative example of how structural neuroplasticity works.
They’ve spent years cultivating intricate knowledge of the entire grid of London streets.
The grooves have been worn deeply.
The more they’ve practiced that mental training, the more automatic and quickly their decisions about routes and shortcuts become.
The neural connections regarding directions and locations are incredibly strong and resilient, and it becomes easy to jump from one thought to the next.
It’s not just because they have quick reflexes or physical stamina: it’s because their brains have been conditioned through experience and practice over a long and hopefully profitable period of time.
When one thought is sparked, the associated thoughts that come after it fire more quickly and reliably the more we train it.
Think of it as the taxi driver being able to recall one street and then suddenly being able to summon a mental picture of the entire neighborhood.
Structural neuroplasticity is really what underlies most of the changes we see and the ones we want.
If you want to break a bad habit of smoking, it requires repetition of the behavior you want (not smoking, or rather satisfying your urges in another way, such as chewing gum) so that particular groove becomes worn and the action of not smoking becomes easy and natural.
Learning is nothing but creating and strengthening connections between independent pieces of information.
Overcoming fears requires consciously digging the groove of courage and acknowledging that you will be fine no matter what happens.
Discipline is about creating the groove of delayed gratification and comfort with discomfort.
Accordingly, structural neuroplasticity is what this book focuses on.
If you have a thought, it causes a neural change.
If you keep having the same thought, it becomes a positive feedback loop that reinforces and cements the change.
In this way, your past does not determine your future.
What determines it is only what you think in this very moment, and what you think in the future.
All of your thoughts, actions, and behaviors are being recorded somewhere, and every day we have the choice of how we want to program our brains.
Functional neuroplasticity is much less common, as it involves the brain’s ability to improve or retain functionality in cases such as when the brain is damaged.
This involves more dramatic change of the cortical remapping variety.
Consider the amputees with phantom limbs we discussed in Chapter 1.
Their neural pathways were creating sensations that didn’t correspond to anything in the real world; they still felt the presence of something that wasn’t there.
That’s because an area of the brain was starting to take over another area’s functioning.
Remember that the homunculus is a shining example of how functional neuroplasticity works.
Studies showed that parts of the brain that regulate the face are perilously close to the parts that affect the hand—over time, for amputees, the functionality of those unused brain structures was slowly subsumed by its neighbors.
So while a natural curiosity, functional neuroplasticity is not likely something we can create without extreme sensory deprivation or unfortunate circumstances.
The Process of Neuroplasticity
The etymology of neuroplasticity is simple: the prefix neuro- refers to nerves or nerve cells, and plasticity refers to a certain object’s capability of being molded or changed.
Dr. Michael Merzenich defined neuroplasticity as “the brain’s ability to change its anatomical, neurochemical, and functional performance status across the lifespan.”
Any given person’s brain is different because their neuroplasticity has been entirely unique.
Your thoughts, activities, behaviors, beliefs, and experiences all have direct impact on the shaping of your brain.
Because nobody besides you has ever been through what you’ve been through, that means your brain’s been molded by a completely singular series of patterns nobody else can ever quite duplicate—which means, in turn, that your brain is the only one of its kind.
Neuroplasticity happens from the moment one is born.
A newborn baby’s brain is a total blank slate, entirely uninformed.
But it’s structured to start taking input right away—its cerebral cortex is ready to build its complex neural pathways.
The first few years of a child’s life are the time when its brain development is the fastest, but not necessarily because the young brain is more malleable.
Information is being constantly created and analyzed and it’s coming in fast.
Again, this is primarily structural neuroplasticity in creating synaptic connections and strengthening existing ones.
As the child grows into an adolescent, some parts of the massive influx in the brain that’s happened to them become unnecessary to retain.
That’s when the brain starts going through something called synaptic pruning: it gets rid of the synapses that we haven’t been using and keeps the ones that we have used most often.
By the time a child reaches the age of 10, he or she has already dumped half of all the synapses they had at the age of two.
(This is why we rarely remember anything from the first two years of our lives.)
When we become adults, our brain development cools off from the rapid-fire pace it experienced as kids.
As we advance in age, we do lose brain cells and certain neural connections in the interest of efficiency and laziness.
We begin to lose brain cells at a higher rate than we form new ones, and this is what causes many elderly people to suffer mental decline.
However, what we don’t lose as we get older is the brain’s ability to rewire itself.
We might drop a couple of brain cells (well, more than just a couple), but we never lose the ability to alter and strengthen our neural pathways.
We can change how our synapses fire and the connections that we build.
Learning and having new experiences are the primary ways we restructure our neural pathways.
Taking on new skills or knowledge directly affects the function and organization of our synapses, and that can happen at any time.
It’s something we actually can control.
And we actually should, because neuroplasticity doesn’t always have a positive result.
Brainpower is a lot like muscle power in that if you don’t use it, you lose it.
If one doesn’t use a certain neural connection regularly, it dies off.
Certain parts of the brain even decrease in size if they’re not regularly employed.
That’s not terrible in and of itself—a concert pianist isn’t going to use all the same brain functions that a lumberjack does, so they’re just not going to need them.
But on the other hand, by not developing and thereby losing synaptic exchanges, we could be limiting our own potential.
There are also certain neural connections that aren’t positive at all.
Bad physical habits, substance abuse or addiction, and negative self-talk can also become encoded and entrenched in neural pathways.
The brain’s reward system doesn’t always distinguish between helpful pleasures and harmful ones.
The hippocampus remembers and encodes the pleasure one might get from the taste of cheese puffs, driving 100 miles an hour, or the high of a drug just the same as it processes the happiness of getting a diploma or falling in love.
All the amygdala knows is that it feels great and it develops a conditioned response—its neural pathways are set, and not for the best.
Scientists have also found a difference between the neural pathways of domesticated and wild animals—namely, that domestication can have adverse effects on neuroplasticity.
The more civilized a being becomes, the smaller their brain gets.
For example, a domesticated dog has a smaller brain than its relative, a wild coyote.
Anthropologists have discovered this disparity in the process of human history, as well.
Believe it or not, the brains of humans from 10,000–20,000 years ago were physically bigger than the ones we have now.
That’s the type of neural engagement that comes with a constant hunt for food and shelter and rarely having a moment for leisure or relaxation.
Contrast that to today’s preferred leisure activities, most of which include sitting still for extended periods of time.
Although it’s a bit late for us to do anything about that, it does lend some credence to the idea that taking occasional chances and chasing unfamiliar experiences is more mentally beneficial than staying within our safe, comfortable, unchallenging existences.
The less challenge and unfamiliarity, the less our brains have to work and adapt, and this is a negative consequence of our easier, modern lifestyles.
Inducing the neuroplasticity we want is inherently tough and uncomfortable, precisely because it involves unfamiliarity and wearing a new groove where none existed before.
It’s inevitable that our brains will change and develop throughout our lives.
But again, it’s something we can control.
It forces us to become a lifelong learner.
The more we engage and expose our brains to new challenges, the more we actually, physically reshape the structure of our neuronal networks.
Studies have shown, for example, that taking art lessons have a direct impact on our fluid intelligence, attention span, and even overall IQ.
Making music has been linked to better memory, increased learning ability, and greater attention span as well.
We’ll talk more about this notion in the following chapter on guiding principles for beneficial neuroplasticity.
What’s more, these positive effects happen in both children and adults—further proof that neuroplasticity can happen at any time and any age.
The Debate of Neuroplasticity
Scientists didn’t always agree that the brain was capable of changing itself.
Up until fairly recently, the general belief was that the brain only grew in infancy and childhood and that by the time one hits early adulthood the brain is done growing and its structure was set in stone.
Researchers believed that neurogenesis—the formation of new neurons—ended shortly after birth.
This belief persisted in ancient times because the brain was considered fairly fixed and was believed to decrease in pure ability the older one got.
Later minds believed that the inability of certain brains to recover from damage proved it was essentially finite.
In that context, they weren’t able to observe how the brain functioned or behaved on a microscopic level (which of course changed once advanced technology became available), and thus they had no reason to think differently.
But even during those pre-modern times, there were outliers who thought there was more to brain function that wasn’t quite being picked up.
In 1980, psychologist William James wrote in his book The Principles of Psychology that he observed “an extraordinary degree of plasticity” in organic matter—especially “nervous tissue,” the fundamental building block of neurons.
Researcher Karl Lashley observed evidence of brain transformation in his study of rhesus monkeys.
And just before brain science took a great leap forward in the 1960s, doctors noticed that certain older stroke victims could regain at least a little of their brain functionality.
He might not have pictured it to be as complex as the cortical remapping we’ve discussed, but this spurred him to suppose that neuroplasticity, or some form of neural regeneration, was possible.
It wasn’t until Dr. Michael Merzenich ran experiments in the early ’70s that we obtained confirmation that the brain can change itself.
Ironically, the goal of Merzenich’s project was to prove the opposite—that the brain, for all intents and purposes, is set in stone, and once a part of it is damaged, what it once knew can’t be relearned.
Instead, Merzenich discovered that the entire brain is essentially one fluid learning organ that functioned as a whole: that if a skill is lost through damage to a particular part of the brain, other parts can potentially learn it as well.
This gets us back to the homunculus, the “little man” that best describes the process of cortical remapping.
Merzenich found that if, say, the cortical map of the “hand” was blocked from sensory input and therefore inoperative, it could be reanimated through the stimulation of other cortical maps close to the hand on the homunculus—for example, the forearm or even the eye.
It was a clear indication that the brain was capable of adapting in ways that were real and tangible.
Primary Aspects of Neuroplasticity
Merzenich’s “discovery” of neuroplasticity obviously merited more research into the topic.
It was a monumental discovery that could help answer questions not only about recovery and health care but in peak mental performance and boosting the brain power that we are born with.
In the years since his findings on neuroplasticity, the scientific community has made more determinations about the process that furthered our understanding of it.
Brain plasticity varies according to age.
Although neuroplasticity is a lifelong process, younger brains are more apt to grow and develop systems of organization.
Therefore, the brains of young ones are more sensitive and receptive to certain stimuli than those of older people.
You’ve probably heard that it’s nearly impossible to become fluent like a native in a language if you learn it as an adult.
While not a hard rule, there is some scientific grounding for this claim.
It involves more than just neural processes.
Nerve cells don’t operate alone when it comes to neuroplasticity: they do have a support staff.
In particular, glial cells help to support and insulate neurons.
Vascular cells, which carry nutrients throughout the body, are also important in the process (and might explain why good nutrition is especially important in neuroplasticity, along with everything else).
Everything about the structure changes.
Brain plasticity happens in one of two ways.
The preferred manner, of course, is through learning, experience, and memory, all of which contribute to shaping and defining the neural passageways.
But it can also happen through damage to the brain, such as when it suffers through a stroke.
Even then, damage from a stroke can be repaired.
As mentioned, this is the difference between structural and functional neuroplasticity.
Environment is important in brain plasticity.
A primary conduit of neuroplasticity is what we experience, which naturally comes from our immediate surroundings and what we go through day to day.
Genetics may play a role as well, but at this point we know that neuroplasticity is a direct result of what the brain is exposed to over a period of time.
If you are in an environment that forces a certain set of actions, thoughts, behaviors, or habits, then you’re left with no choice but to change and adapt.
We’ll talk more about this soon, as this is known as using an enriched environment.
That’s pretty much what it sounds like: a set of surroundings that make up a supportive and thoughtful place for quality mental and physical stimulation.
What comprises an enriched environment is obviously different for everyone, but it’s shown to stimulate production of new brain cells, especially in the parts of the brain that regulate mood and memory.
Whether it’s a place where one can more effectively learn without too much anxiety or simply get some quality sleep to create and prune synaptic connections, there’s a lot of truth to the notion that being in the right environment is key, even in neuroplasticity.
Brain plasticity isn’t always good.
As I mentioned earlier, certain kinds of neuroplasticity—those that arise from drug use, bad habits, and negative self-talk—isn’t what we’d call the “good” kind.
Phobias, anxiety, and fear are genetic and instinctual from years of evolution, but many are learned through repetition, just like the multiplication tables or the capitals of the countries of the world.
From Synaptic Pruning to Neurogenesis
We now understand that the brain doesn’t become a stationary object after a certain point in life.
Synaptic pruning doesn’t just whittle our brains down to nothing after a while.
The brain actually continues to manufacture new brain cells and new neural passageways.
Thanks to extensive research in the area, we also now know that there are things we can do to stimulate increased production and improvement of brain cells, which we call neurogenesis.
The brain starts making new cells when we’re still in the womb.
The fetal brain eventually creates almost a trillion new neurons in the nine months between conception and birth.
That number is eventually reduced through synaptic pruning to about 100 billion, which is about the number that we maintain for the rest of our lives.
Pruning and modification, as we’ve discussed, comes through experience determining which neural pathways we use and which we don’t.
Once we’re born, the production of new brain cells slows down, and the production remains definitely in only two parts of the brain.
One is the hippocampus, our main source of learning and memory.
The other is the subventricular zone, which produces more neural cells than any other region in the brain for eventual distribution to the forebrain.
Other studies have suggested, though not conclusively, that the subventricular zone also sends brain cells to the olfactory bulb (which handles our processing of new smells).
But then again, the sense of smell is strongly related to memory, and it is common for smells to conjure up far-away and long-ago situations and people.
Almost any activity that engages the mind has been shown to stimulate the production of brain cells—including mental activities like psychotherapy, performing stimulating tasks, learning, and even just reflecting on our thoughts (especially the positive ones).
But it can also be generated through physical activities like exercise.
Additionally, certain medications have been shown to stimulate neurogenesis.
In both neural pathway generation and synaptic pruning (which actually doesn’t stop until we’re well into our 20s), our brain creates new connections through the growth of dendrites and axons, especially during sleep.
The production of new pathways and the deletion of unused ones is informed by our personal experiences and what we think, do, or say.
Creation of new connections is impacted by almost anything that interacts with the brain: words, thoughts, memories, meditation, heightened attention, and especially new learning.
The new cells that form in the hippocampus are especially linked to learning: they’re much more likely to respond to brand new information than older neurons, are more moldable, and are more capable of learning and memorizing newly introduced, complicated concepts.
The formation of new neural connections—especially important to consider, since we never stop making new ones even after brain cell production slows down—is particularly responsive to mindful activities.
There are several factors that work against neuroplasticity.
Lack of sleep is one of the most damaging, and high levels of stress and gastrointestinal disorders have also been shown to have a negative impact.
And despite the fact that our neural activity doesn’t stop as we get older, the stimulation of new brain cells does decrease with age.
That’s really what causes seniors to degrade, not necessarily a high level of synaptic pruning.
There is some level of control we can exert over those factors (except getting older), so monitoring them and their effects on our lives is a key step in directing our brain plasticity.
At this point, you understand the brain and just what it takes to effect change upon it.
The neural growth you desire is within your grasp, as are the benefits that come with it.
When you view your mental performance as a result of the number of neuronal connections you cultivate, or the greater number of dendrites you recruit on a daily basis, it suddenly becomes very clear how to build a better brain.
In the next chapter we’ll examine some of the key principles of neuroplasticity in finer detail.
Takeaways:
• What is neuroplasticity?
We’ve perhaps danced around it, but we get down to the details here.
It is the changes in your brain that are neutral by themselves and simply a reflection of our actions, thoughts, habits, environments, and so on.
• There are two types: structural and functional.
Structural neuroplasticity concerns strengthening and creating neural connections over time, while functional is what happens when specific parts of the brain lose functionality and are compensated for by neighboring brain elements.
Phantom limb sufferers who unknowingly utilize cortical remapping are using functional neuroplasticity, while learning new habits and information comes through structural changes.
• We mainly seek structural neuroplasticity for obvious reasons.
One study in particular illustrates what neuroplasticity is all about: scientists have determined that animals that have been domesticated have smaller brains, and they’ve found that this finding also applies to human beings.
Thus, neuroplasticity’s changes aren’t always positive or beneficial.
That’s why we must be proactive and intentional—the more challenge, discomfort, and effort spent, the more neuroplasticity will occur and the higher functioning our brains will be.
• Neuroplasticity was first thought to be impossible and then thought to be reserved only for children.
Both of these notions were eventually proven wrong over time.
Though we still suffer synaptic pruning throughout our lives, neuroplasticity also occurs throughout our lives, and neurogenesis has even been found in select portions of the brain, specifically those related to smell and memory—which, coincidentally, have been found to be related to each other.
The brain changes and adapts only to what it experiences, and this is within our control.
Well, we've had a journey through the world of neuroplasticity with Peter Hollins on this
episode.
Let's wrap up with a few key takeaways.
Neuroplasticity is essentially your brain's ability to change and adapt, which occurs
as a result of our actions, our thoughts, and our environment.
It's a powerful tool that shapes who we are and how we function.
There are two main types, structural neuroplasticity, which focuses on strengthening neural connections,
and functional neuroplasticity, where different parts of the brain compensate for each other's
loss of functionality.
It's structural neuroplasticity that helps us learn new habits and gain knowledge.
But it's important to remember that not all changes are positive.
Our brains can actually shrink when we don't challenge them, so we need to intentionally
create opportunities for growth and learning throughout our lives.
After all, neuroplasticity isn't just for kids, it happens at every age, thanks in part,
to the discovery of neurogenesis in certain areas of the brain.
The key is to embrace challenges and discomfort, because that's when real transformation occurs.