Unlocking the Brain's Secrets: How We Learn New Things

Learning is a fundamental aspect of the human experience, allowing us to adapt, grow, and thrive in an ever-changing world. But what exactly happens inside our brains when we acquire new knowledge or skills? Scientists have long been fascinated by this question, and recent advancements in neuroscience are beginning to unravel the intricate mechanisms that govern how the brain learns.

The Ever-Changing Brain: A Foundation for Learning

At any age, learning something new profoundly impacts the brain. After you learn something new, your brain is never the same again. Every time we learn something new, our brain forms new connections and neurons and makes existing neural pathways stronger or weaker. This remarkable ability of the brain to reorganize itself by forming new neural connections throughout life is known as neuroplasticity.

Synaptic Plasticity: The Key to Brain Adaptation

The broad answer is that our brains undergo adaptations to accommodate new information. Such modifications are orchestrated across trillions of synapses - the connections between individual nerve cells, called neurons - where brain communication takes place. In an intricately coordinated process, new information causes certain synapses to get stronger with new data while others grow weaker. Neuroscientists who have closely studied these alterations, known as “synaptic plasticity,” have identified numerous molecular processes causing such plasticity.

Neurons are the fundamental building blocks of the brain, and they communicate with each other through specialized junctions called synapses. These synapses are not static structures; they are constantly changing in response to experience. When we learn something new, certain synapses become stronger, making it easier for neurons to communicate with each other. Conversely, synapses that are not used regularly weaken, eventually fading away.

Multiple Rules for Neurons

University of California San Diego neurobiologists William “Jake” Wright, Nathan Hedrick and Takaki Komiyama have now uncovered key details about this process in a study partially funded by the National Institutes of Health. As published April 17 in the journal Science, the researchers used a cutting-edge brain visualization methodology, including two-photon imaging, to zoom into the brain activity of mice and track the activities of synapses and neuron cells during learning activities. With the ability to see individual synapses like never before, the new images revealed that neurons don’t follow one set of rules during episodes of learning, as had been assumed under conventional thinking. Rather, the data revealed that individual neurons follow multiple rules, with synapses in different regions following different rules. “When people talk about synaptic plasticity, it’s typically regarded as uniform within the brain,” said Wright, a postdoctoral scholar in the School of Biological Sciences and first author of the study. Finding that neurons follow multiple rules at once took the researchers by surprise.

Read also: UCF Application Strategies

Memory Formation: From Short-Term to Long-Term

Everything you learn goes first to your short term memory, and some of it transfers later to long term storage in your brain. Sleep is often important to transferring something from short to long term memory, which is why memory loss can occur with sleep deprivation. The process of converting short-term memories into long-term memories is known as consolidation, and it involves complex interactions between different brain regions, including the hippocampus and the cortex.

The Role of Emotions in Learning

Learning something new is often exciting for the learner. According to Oprah.com, novel experiences cause a rush of dopamine, which not only makes learning seem exciting but also makes you want to repeat the experience. Emotions play a significant role in learning and memory. When we experience something emotionally arousing, our brains release neurotransmitters that enhance memory consolidation, making it more likely that we will remember the event later.

Fear and Memory

Many of the research questions surrounding memory may have answers in complex interactions between certain brain chemicals-particularly glutamate-and neuronal receptors, which play a crucial role in the signaling between brain cells. Huganir and his team discovered that when mice are exposed to traumatic events, the level of neuronal receptors for glutamate increases at synapses in the amygdala, the fear center of the brain, and encodes the fear associated with the memory. Now Huganir and his lab are developing drugs that target those receptors. Post-traumatic stress disorder (PTSD): A disorder in which your “fight or flight,” or stress, response stays switched on, even when you have nothing to flee or battle. The disorder usually develops after an emotional or physical trauma, such as a mugging, physical abuse or a natural disaster.

Encoding and Types of Learning

Encoding is when you first encounter information. Your brain processes what you see, hear, or experience and turns it into something that can be stored. Once encoded, the information needs to be saved somewhere for later use. Your brain stores this information in short-term or long-term memory.

Not all learning is the same. Declarative learning, for example, occurs when you learn facts or information, like remembering your friend’s birthday or the name of a movie star. This kind of learning is conscious-you actively try to store and recall the information. On the other hand, procedural learning is about knowing how to do something. Take learning to ride a bike. That’s procedural learning. It’s more about mastering a skill through repetition, and it’s usually unconscious once you get the hang of it.

Association is another way we learn. In classical conditioning, you associate one thing with another. Pavlov is a famous psychologist known for this type of learning. He trained dogs to salivate at the sound of a bell because they came to associate the bell with food over time. Instrumental conditioning involves learning by rewards and consequences. For example, if you study hard and get good grades, you’re more likely to keep studying because the good grades are your rewards.

The Importance of Practice and Repetition

As we learn, our brains are constantly changing and adapting. This ability is called neuroplasticity. Think of your brain like a muscle-the more you use it, the stronger and more flexible it becomes. When you learn something new, your brain creates new pathways and connections between neurons (brain cells). The more you practice or repeat the activity, the stronger these connections get. This is why practice is so important in learning.

Myelin: Insulating for Speed and Efficiency

Myelin makes the signals in our neurons move faster, and when you learn new things, especially at older ages, it helps more myelin get onto our nerve axons so that our brain is more connected and feels like it works faster and better. Myelin is a fatty substance that wraps around nerve axons, acting as an insulator and increasing the speed and efficiency of neural transmission. When we learn new skills, the brain produces more myelin, which helps to strengthen neural connections and improve performance.

Glial Cells and Myelination

In the early 1990s my lab at the National Institutes of Health and others began to explore the possibility that glia might be able to sense information flowing through neural networks and alter it to improve performance. Experimental evidence that has accumulated since then shows that all types of glial cells respond to neural activity and can modify information transmission in the brain. Myelin insulation is formed by layers of cell membrane wrapped around axons like electrical tape. In the brain and spinal cord, octopus-shaped glial cells (oligodendrocytes) do the wrapping. In the limbs and trunk, sausage-shaped glial cells (Schwann cells) perform the same task.

If oligodendrocytes sense and respond to the information traffic flowing through neural circuits, then myelin formation and the way it adjusts impulse-transmission speed could be controlled by feedback from the axon. Over the past 20 years our research and that of other labs has succeeded in identifying many neurotransmitters and other signaling molecules that convey to glia the presence of electrical activity in the axon to stimulate myelination. Our experiments have shown that when a neuron fires, neurotransmitters are released not only at synapses but also all along the axon. We found that the “tentacles” of the octopuslike oligodendrocytes probe bare sections of axons in search of neurotransmitters being released from axons firing. When a single tentacle touches an axon that is firing, it forms a “spot weld” contact, which enables communication between the axon and the oligodendrocyte.

So it may be that as a person learns to play “Für Elise” on the piano, bare axons are wrapped with myelin or the volume of existing sheaths is increased in circuits that are activated repetitively during practice, which speeds information flow through brain networks. Several labs have recently verified that action potentials, signals coursing the length of axons, stimulate myelination of these exposed areas of neural wiring. In 2014 Michelle Monje’s lab at Stanford University showed that optogenetic stimulation (using lasers to make neurons fire) increased myelination in the mouse brain. That same year William Richardson’s lab at University College London demonstrated that when the formation of new myelin is prevented, mice are slower to learn how to run on a wheel with some of its rungs removed.

Constraints on Learning: Pre-Existing Neural Structures

The human brain is "plastic": it can adapt and rewire itself, often more easily when learning new things related to familiar skills. For example, it is probably easier for a professional tennis player to learn to play badminton than soccer. Seeking to discover basic limits on the brain's plasticity, a new Caltech study discovered that learning is indeed easier when related to skills one already has because pre-existing neuronal structure constrains what one can learn. In other words, it is likely that the skills we already have developed restrict what we can learn easily in a short time.

The researchers found that the participant was sometimes able to adapt to perturbations in the cursor's movement by altering her cognitive strategy. For example, she would say that she re-aimed the cursor movement in her mind to perform the task. However, the participant was not always able to solve the mapping perturbation by adopting a new cognitive strategy, and in those cases, the researchers found, her brain did not generate totally new patterns of neuronal activity. In other words, her adaptability-specifically, her ability to re-aim the cursor to certain locations in space-was constrained by the tuning of the particular set of neurons being recorded from. This suggests that the extent to which a person can learn a new skill is constrained by pre-existing neural wiring.

The Role of Causality in Learning

Memories of significant learning experiences - like the first time a driver gets a speeding ticket - are sharp, compared to the recollection of everyday events - like what someone ate for dinner two weeks ago. That’s because the human brain is primed to learn from helpful associations. Carnegie Mellon University researchers have identified specific neural connections that are especially sensitive to this process of learning about causality.

“Our brains are wired to understand how one thing causes another,” said Alison Barth, Maxwell H. and Gloria C. Connan Professor in the Life Sciences at the Mellon College of Science and member of the Neuroscience Institute. “And when you're first trying to learn something, it's a very special time.” Led by Park, researchers looked at how the connection between two different types of neurons - cells that transmit information to different parts of the brain - changes in response to new learning experiences. They found that the strength of the connection only changed if an experience was meaningful.

Park and the team studied the behavior of mice, using them as a model to understand how learning happens in the brain. She observed how mice responded in three different scenarios. In one group, when mice received a puff of air on their whiskers (the stimulus), they always got a reward. In another group, when mice received the air puff, they got a reward sometimes, but not always. In a third group, mice received a reward without any stimulus. When the reward wasn’t reliable, Park observed two important things: The mice quickly learned to ignore the stimulus and there was no change in the neurons’ behavior. “This means that somehow the brain can distinguish whether there is a useful association to make, or there is nothing to learn,” Park said.

Beyond Synapses: A Broader Perspective on Learning

Learning and memory require the coupling of information from many different brain regions. Our concepts of how the two and a half pounds of flabby flesh between our ears accomplish learning date to Ivan Pavlov’s classic experiments, where he found that dogs could learn to salivate at the sound of a bell. In 1949 psychologist Donald Hebb adapted Pavlov’s “associative learning rule” to explain how brain cells might acquire knowledge. Hebb proposed that when two neurons fire together, sending off impulses simultaneously, the connections between them-the synapses-grow stronger. When this happens, learning has taken place.

But not everything we remember results from reward or punishment, and in fact, most experiences are forgotten. Even when synapses do fire together, they sometimes do not wire together. What we retain depends on our emotional response to an experience, how novel it is, where and when the event occurred, our level of attention and motivation during the event, and we process these thoughts and feelings while asleep. It turns out that strengthening a synapse cannot produce a memory on its own, except for the most elementary reflexes in simple circuits. Vast changes throughout the expanse of the brain are necessary to create a coherent memory.

Structural Changes in the Brain

If synaptic changes alone do not suffice, what does happen inside your brain when you learn something new? Magnetic resonance imaging methods now enable researchers to see through a person’s skull and examine the brain’s structure. In scrutinizing MRI scans, investigators began to notice differences in the brain structure of individuals with specific highly developed skills. Musicians, for example, have thicker regions of auditory cortex than nonmusicians.

The kind of learning that leads to alterations in brain tissue is not limited to repetitive sensorimotor skills such as playing a musical instrument. Neuroscientist Bogdan Draganski, currently at the University of Lausanne in Switzerland, and his colleagues witnessed increases in the volume of gray matter in medical students’ brains after they studied for an examination. Many different cellular changes could expand gray matter volume, including the birth of new neurons and of nonneuronal cells called glia. Vascular changes and the sprouting and pruning of axons and dendrites that extend from the main body of a neuron could also do the same.

Remarkably, physical changes in the brain can happen much faster during learning than might be expected. Yaniv Assaf of Tel Aviv University and his colleagues showed that 16 laps around a race track in a computerized video game were enough to cause changes in new players’ hippo campal brain region. Structural alterations in the hippo campus in these gamers make sense because this brain region is critical for spatial learning for navigation.

White Matter and Learning

These fiber bundles are white because the axons are coated with a fatty substance called myelin, which acts as electrical insulation and boosts the speed of transmission by 50 to 100 times. In the past 10 years studies have begun to find differences in white matter in brain scans of experts with a variety of skills, including people with high proficiency in reading and arithmetic. Expert golfers and trained jugglers also show differences in white matter compared with novices, and white matter volume has even been associated with IQ.

Astrocytes and Myelin Sheath

Surrounding the node of Ranvier is a glial cell called an astrocyte. Astrocytes have many functions, but most neuroscientists have largely ignored them because they do not communicate with other cells through electrical impulses. Surprisingly, research in the past decade has shown that astrocytes positioned close to the synapse between two neurons can regulate synaptic transmission during learning by releasing or taking up neurotransmitters there. Thrombin is made by neurons, but it also can enter the brain from the vascular system. As the myelin lifts off the axon, the amount of bare axon at the node of Ranvier increases. The outer layer of myelin is attached to the axon adjacent to the perinodal astrocytes. When the myelin is detached from the axon, the outer layer withdraws into an oligodendrocyte, thinning the sheath.

Our experiments support a new hypothesis: the myelin sheath’s changes in thickness represent a new form of nervous system plasticity governed by the addition and subtraction of myelin. The optimal timing of action potentials at relay points is critical for strengthening synapses by adjusting their timing to allow them to fire together.

Neurogenesis: The Birth of New Neurons

Neurons are nerve cells that send messages all over your body to allow you to do everything from breathing to talking, eating, walking, and thinking. Until recently, most neuroscientists (scientists who study the brain) thought we were born with all the neurons we were ever going to have. As children, we might grow some new neurons to help build the pathways-called neural circuits-that act as information highways between diﬀerent areas of the brain. However, scientists believed that once a neural circuit was in place, adding any new neurons would change the flow of information and break the brain’s communication system

In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons traveled from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman’s findings in the rat brain; and in 1983, he found special kinds of cells-called neural precursor cells-with the ability to become brain cells like neurons, in adult monkeys. Other scientists, like Elizabeth Gould, later found evidence of newborn neurons in a distinct area of the brain in monkeys. Still, scientists are intrigued by current research on neurogenesis and the possible role of new neurons in the adult brain for learning and memory.

Neuronal Migration and Differentiation

Once a neuron is born, it must travel to the place in the brain where it will do its work. Scientists have seen that neurons use at least two different methods to travel: Some neurons travel, or migrate, by following the long fibers of cells called radial glia. These fibers stretch from the inner layers to the outer layers of the brain. Neurons glide along the fibers until they reach their destination. Neurons also travel by using chemical signals. Scientists have found special molecules on the surface of neurons-adhesion molecules-that attach to similar molecules on nearby glial cells or nerve axons. These chemical signals guide the neurons to their final location.

Not all neurons are successful in their journey. Scientists think that only a third reach their destination. Some cells die in development or while traveling. Other neurons survive the trip but end up in the wrong place. Once a neuron reaches its destination, it must settle into work. There is still a lot that scientists don’t understand about this part of neurogenesis, called differentiation.

How Learning Changes the Brain

Did you always think that learning was due to the addition of new cells in the brain? Then, you’re not the only one! While actually, this is not true, and this is what we call a neuromyth. Learning is due to the creation of new and mostly more efficient connections between brain areas. To understand how learning occurs in the brain, we need to start with the basics. Our brain consists of billions of neurons. These neurons have dendrites, which receive information, and an axon, which sends information. Neurons communicate with each other via electrical and chemical signals. Transmission within a neuron is electrical, and this is called an action potential. Once an action potential reaches the presynaptic neuron, neurotransmitters are released in the synapse and received by the postsynaptic neuron.

If two neurons frequently interact, they form a connection that allows them to transmit messages more easily and accurately. Let’s say you would like to learn to play the piano. When playing the piano, different brain areas are involved, such as the motor, auditory, and visual cortex. Before you start to learn how to play the piano, the pathways between these brain areas are still very weak, and playing the piano doesn’t sound really nice. At this stage, you can compare your brain to a forest without any trails. However, the more you practice the piano, the stronger the connections between the involved neurons in the brain areas get, which leads to faster and more efficient signals. Just like in the forest, the more you use the same trail, the easier the walk becomes. When you have not played the piano in a long time, the connections between the involved brain areas weaken, and so do your piano skills. However, when you have mastered playing the piano, the connections between the neurons have become so strong, that it doesn’t matter that you haven’t played in a while. Just like in the forest, if you have a strong trail, the vegetation is not able to grow back on again.

Strategies for Effective Learning

Understanding the basics of how people learn can help you improve your own learning strategies. Practice and repetition are key. If you want to master a skill, keep practicing. Reduce cognitive load. Use spaced learning. Don’t cram. Stay positive.

Managing Cognitive Load

Have you ever felt like your brain was overloaded when trying to learn something new? That’s because our brains have a limited capacity for processing information at once. This is known as cognitive load. Breaking tasks into smaller chunks can help reduce cognitive load, making learning easier. Instead of cramming all your study into one session (which we’ve all tried before), it’s better to spread your learning over multiple sessions with breaks in between.

Using Emotions

When you’re stressed, anxious, or bored, it’s harder to focus and remember things. On the other hand, positive emotions, like curiosity and excitement, can improve learning by making you more engaged. That’s why creating a positive, relaxed environment can make learning more effective.

Avoiding Boredom

A British research study showed that being bored (which occurs when you don’t learn new things very often) can be dangerous to your health. Not having new experiences and learning new things will slow your brain down and make it less responsive. CCSU offers many opportunities to learn new things at any age through continuing education courses taught by expert faculty with real-world experience in their respective areas.

tags: #how #does #the #brain #learn #new