How the brain works

How the Brain Works

Neuropsychology for Dummies.

A Complex System

The human brain is a complex organ, made up of around 100 billion interconnected neurons. To paint it with a broad brush, their job is recognizing stimuli. How they work in concert to do this is complicated and still not wholly understood. However, one way to explain the process is to follow neuroscientist Paul D. MacLean and break it down into three basic parts, the so-called triune brain: the brain stem, the limbic system, and the cortex. (Note: this model of the brain is no longer accepted as being scientifically accurate, but it still serves well as an introduction to neuropsychology.)

The Reptilian Brain

The brain stem is often regarded by neuroscientists as the simplest of the brain structures. Simple life forms, such as reptiles, have brains consisting almost completely of structures resembling the human brain stem, which extends down to the spinal cord. Consequently, this is sometimes called the “reptilian brain”.

In all animals, it is this part of the brain that maintains basic life and motor functions, e.g. heart rate, breathing, sleeping, eating, etc.

The Emotional Brain

The limbic system is located in the central region of the human brain — just above the brainstem and below the cortex. Often referred to as the “emotional brain,” this grouping of brain structures is involved in regulating motivation, emotion, learning, and memory. Make note there: this is the seat of motivation. If you’re interested in how to motivate change — be it as part of a social movement or simply in order to get people to buy more — this is something you should study more.

The Logical Brain

The cortex, in particular the prefrontal cortex, is especially developed in humans. As such, it is implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior. In other words: attention and logic. That’s why it’s often referred to as the “logical brain.” Important to note in that list is the word “expression” — it is in the prefrontal cortex that the structures associated with communication, e.g. language (speaking, reading, comprehension) are to be found.

Beyond communication, the prefrontal cortex is also implicated in giving us our sense of self:

There’s a region of the brain called “medial prefrontal cortex” that essentially sits between your eyes. This region has been shown again and again to be activated the more a person is reflecting on themselves. It is the region that most clearly and unambiguously is associated with “self-processing.” If you think about your favorite flavor of ice-cream, precious personal memories, or consider aspects of your personality (e.g. Are you generous? Are you messy?) you are likely to recruit this brain region.

This is an important observation for any organization wanting to motivate others to do something. That’s because imposing on people to change who they are or how they act has the potential to invoke in them an acute stress response. Why is this? Follow the energy cycle.

Energy Consumption

The brain is a “selfish” organ in that it strives to reserve as much energy as possible. Within the brain, the prefrontal cortex requires far more energy than the limbic system and the brain stem. It’s difficult — even impossible — to engage both systems at the same time.

Evolution has designed us to conserve energy. Survival has often meant having energy reserves to overcome some difficulty in the environment. Today, we have inherited bodies that maintain this habit.

Under normal circumstances, a person makes decisions first based on emotion, and only then do they rationalize their decision with logic. That is, when confronting new information, people tend to revert to activities associated with the limbic system, and only occasionally engage their prefrontal cortex. We’ve all experienced this: just think about the last time you argued with someone who you thought was being illogical. Why were they acting that way? Simply put, it’s more energy efficient to do so.

That explains how people form opinions from direct observation. When it comes to indirect observation, e.g. someone telling you something — as happens in a classroom or from reading a book, etc. — the process works in reverse. That is, words are perceived first in the prefrontal cortex then passed down to the limbic system. If the listener is tired (i.e., wants to conserve energy), they will be less willing to activate the areas of their brain needed for comprehending what we’re trying to tell them. As a result, our message will never get past the listener’s prefrontal cortex and into the limbic system. Instead, their limbic system might activate to signal annoyance, and the listener’s motivation works against us. This is potentially a huge problem.

So What?

Why is it such a huge problem?

Because, later, after they’ve managed to calm down, they’ll activate their prefrontal cortex to justify their annoyance. That will result in an ingrained opinion that we — the messenger — are annoying. From now on, the listener no longer has to engage their “logical brain” to decide whether or not to listen to us; any future attempts will create stress for them — just like Pavlov’s dogs. As a result, we will be met with an immediate fight-or-flight reaction — an involuntary engagement of the “reptilian brain”: our intended audience will either avoid us or lash out at us. What they won’t do is listen to us. Not good if we’re trying to get someone to change. In effect, we’ve just shot ourselves in the foot.

Now, where this has already happened, we bear the cost of creating new experiences that engage the listener in a new decision-making experiment. That is, something challenges the listener to consider us in a new way, thereby opening up the pathway to the prefrontal cortex anew.

On the other hand, where our audience is not yet aware of us, it behooves us to get started on the right foot. Right?

Now What?

An effective way at getting past the logical brain and into the emotional brain is narrative.

Doing narrative right is part message, part timing, and part presentation. But while these are all necessary, they are not sufficient. What else do you need? Relevance.

Relevance has even more power than either timing or presentation to soften the most reticent mind. But how can you even start to build relevance with an audience who knows nothing about you? I’ll be writing future posts that delve into this. For now, consider reading the next article in my series, “What Narrative Is (and What It Isn’t).”

For this, timing and presentation of the message is important. But while these are necessary, they are not sufficient. Relevance has even more power than either timing or presentation to soften the most reticent mind.

But where does relevance come from? Here’s a good place to start: “The Power of Narrative: Why POV Stories Work (and Why You Should Care).”

How The Brain Works

The body and the mind are fascinating things. Some people wonder how these two elements function together. It’s truly amazing if you think about it. Our thoughts and movements come from our minds, so one can say that our brains are the most important organ in our body. Although a brain is such a fascinating organ, most people have a hard time figuring out how it works. To this day, few people can claim a full and accurate understanding of how the brain works. The number of individuals who are confident and knowledgeable enough to pass on the wisdom to others is even lesser. Since the brain is such a complex part of the human structure, this isn’t at all surprising. However, it is possible to be counted among those selected few who know the ins and outs of the brain. Do you want to be a part of this elite group? Then, you should check out the following information on how the brain works. Let’s delve deeper into this topic so that we can get to the details.

Neurons: The Perfect Union of a Chemical and Electrical Machine

If you look at the most basic blocks that make up the brain, you’ll discover that the complex organ is made up of cells called neurons. There are about 100 billion cells comprising the brain, and they all work together to make sure the brain functions as it should. Just like the switch you use to turn on or off the lights in a room, the neuron has two states: the “off” state, in which it is resting, and the “on” state, in which the neuron transmits an electrochemical impulse.

A neuron has three basic parts: the dendrite (responsible for receiving information from other neurons), the body (supports and maintains the cell), and the axon (the little wire that generates electrical charges and shoots out a chemical to transmit information to other neurons). The substance travels across a synapse, which is the gap between one neuron and another. This chemical, also known as a transmitter, will trigger another neuron to pass the message. There are various types of neurons (sensory neurons, motor neurons, and interneurons being the most basic types), and they utilize various transmitters. These neurotransmitters include dopamine, serotonin, norepinephrine, and epinephrine. The electrochemical nature of neurons, along with the network these cells form throughout the entire body, makes it possible for the brain to control and coordinate all the body’s operations.

The Brain on a Larger Scale

Now that you have a basic idea of the brain’s building blocks, you’re ready to zoom out and tackle the brain on a larger scale. The brain is composed of three main sections of neurons: the brain stem, the cerebellum, and the cerebral cortex.

Connected with the spinal cord, the brain stem acts to relay data between the brain’s upper parts and the spinal cord and peripheral nerves. It is composed of the thalamus, midbrain, pons, and medulla, with each part carrying out certain functions. Some of the operations under the control of the brain stem include basic reflexes, movement of the limbs, blood pressure, heart rate, and digestion. Situated behind the brain stem and making up a third of the brain’s total mass is the cerebellum. It is responsible for arm-leg coordination and balance. Last, but definitely not the least, the cerebral cortex is the part of the brain that controls speech, thought, memory, and other cognitive functions. It is made up of the left and right cerebral hemispheres, both sitting atop the cerebellum and the brain stem.

Focusing on the Cerebral Cortex

Since the cerebral cortex is a multifunctional part of the brain, it deserves its very own section. There are two ways to look at the cerebral cortex – according to its structure and according to its functions.

Structurally, the cerebral cortex can be divided into the left and right hemispheres. These hemispheres are almost a mirror image of the other, and each can be subdivided into four lobes: the frontal lobe, the parietal lobe, the temporal lobe, and the occipital lobe. They got their names from the skull bones that lie on top of them: the frontal bone, the parietal bone, the temporal bone, and the occipital bone. The functions of each of these lobes aren’t really related to one another, except the occipital lobe, which deals solely on vision.

Functionally, the cerebral cortex can be divided into the primary sensory areas, the primary motor areas, and the association areas. The first is in charge of receiving sensory signals and is composed of the parietal lobe’s somatosensory area, the temporal lobe’s auditory area, and the occipital lobe’s visual area. The second division is mainly comprised of the frontal lobe’s rear portion and is responsible for sending signals to the motor neurons located in the spinal cord and brain stem. The last category is the area most involved in complex processes such as decision making, thought, and perception.

Lateralization of Brain Functions

A lot of people are intrigued by the subject on the lateralization of the brain functions. Ever heard people saying that since they’re right-handed, their left brains are more dominant than their right? Have you ever come across the theory that right-handed people are “logical” while left-handed people are “creative”? They may sound illogical at first, but there is reason enough for such concepts to have seen the light of day. If you read further, you’ll understand the issue better.

As previously mentioned, there are two cerebral hemispheres: the right and the left. Their connections to the rest of the body are crossed. That is, the right brain interacts with the body’s left side, and vice versa. While they are almost an exact replica of each other, the hemispheres’ functions are managed in different ways. There are plenty of generalizations crediting right-handed people with a firm sense of logic and left-handed people with creativity, but in actuality, both of these traits can exist for both types. This is supported by the bilateral processing of brain functions including numerical estimation as well as facial perception, auditory and visual stimuli processing, and artistic operations. It is important to note, though, that superiority and dominance may be shown by a certain hemisphere for these functions.

Despite the many studies concerning the matter of lateralization, it is still unclear whether each side of the brain has an area of specialty. There are incidences when parts of a hemisphere, or even the entire thing, are damaged or harmed, and the surrounding areas or the opposite hemisphere pick up the slack. Still, this is dependent on the person’s age and the part of the brain that sustained injuries.

By now, you’ve come to the conclusion that the brain and its functions are a complicated matter that will have even the wisest of men scratching their heads in confusion. Hopefully, you got the gist and now understand how the brain works a little better than before.

We wanted to provide as much information as possible so that it’s clear about how the brain functions. It’s great to use the power of our brains, but it also helps when you know how and why your brain does what it does.

If there are any questions that you still feel are unanswered or you have queries, please reach out to us and let us know what’s on your mind.

The Human Brain

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How Does the Brain Work?

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With 80-100 billion nerve cells, known as neurons, the human brain is capable of some astonishing feats. Each neuron is connected to more than 1,000 other neurons, making the total number of connections in the brain around 60 trillion! Neurons are organized into patterns and networks within the brain and communicate with each other at incredible speeds.

How do neurons work?

Each neuron is made up of three main parts: the cell body (also known as the soma), the axon, and the dendrites. Neurons communicate with each other using electrochemical signals. In other words, certain chemicals in the body known as ions have an electrical charge. Ions move in and out of the neuron across the cell membrane and affect the electrical charge of the neuron.

At the axon terminal, electrical signals are converted into chemical signals that travel between neurons across a small gap called the synapse. These chemicals are called neurotransmitters. Neurotransmitters cross the synapse and attach to receptors on the dendrites of nearby neurons. Dendrites are branch-like projections that carry impulses received from neighboring neurons to the soma

How is the brain organized?

Neurotransmitters are different from ions, because instead of directly affecting the charge of the neurons, neurotransmitters communicate by activating a receptor. In other words, the neurotransmitter is like a key and the receptor is the lock. Once the “key” turns the “lock,” or when the neurotransmitter attaches to the receptor, the message is passed on and the neurotransmitters are recycled. The transmission of information from neuron to neuron, and between networks of neurons, gives rise to everything from thinking to playing sports, solving problems, and even dreaming.

Neurons in the human brain and spinal cord are organized into the central and peripheral nervous systems. The central nervous system is organized into different functional areas:

1) The neocortex, which is organized into lobes seen in the illustration below.
2) The neostriatum or basal ganglia, which can be found deep within the structure.
3) The diencephalon, which contains the thalamus and hypothalamus, and is also found deep within the brain.
4) The brainstem.
5) The spinal cord.

Oftentimes, different lobes and areas work together to accomplish complicated behaviors like talking or learning. Not only are these neurons constantly communicating with each other, but they also interact with neurons in the peripheral nervous system.

The peripheral nervous system is comprised of sensory and motor neurons throughout the rest of your body. The sensory neurons collect information from the outside world through the five senses, while the motor neurons allow you to move and respond to signals from the brain and spinal cord.

When you were born, you had almost all the neurons you will ever have, and many more neuronal connections than you have today. The brain continues to change and grow throughout your lifetime because the connections between neurons are plastic. In other words, your brain can add new connections or subtract unused ones. As you grow up, your experiences and environment help your brain decide which connections are important and useful. In addition to your experiences, genetic information also influences your brain’s development. Although it is very complicated to tease apart what is inherited and what is learned, many behaviors appear to be a combination of both genetic and environmental factors

Brain Anatomy and How the Brain Works

What is the brain?

The brain is a complex organ that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger and every process that regulates our body. Together, the brain and spinal cord that extends from it make up the central nervous system, or CNS.

What is the brain made of?

Weighing about 3 pounds in the average adult, the brain is about 60% fat. The remaining 40% is a combination of water, protein, carbohydrates and salts. The brain itself is a not a muscle. It contains blood vessels and nerves, including neurons and glial cells.

What is the gray matter and white matter?

Gray and white matter are two different regions of the central nervous system. In the brain, gray matter refers to the darker, outer portion, while white matter describes the lighter, inner section underneath. In the spinal cord, this order is reversed: The white matter is on the outside, and the gray matter sits within.

Gray matter is primarily composed of neuron somas (the round central cell bodies), and white matter is mostly made of axons (the long stems that connects neurons together) wrapped in myelin (a protective coating). The different composition of neuron parts is why the two appear as separate shades on certain scans.

Each region serves a different role. Gray matter is primarily responsible for processing and interpreting information, while white matter transmits that information to other parts of the nervous system.

How does the brain work?

The brain sends and receives chemical and electrical signals throughout the body. Different signals control different processes, and your brain interprets each. Some make you feel tired, for example, while others make you feel pain.

Some messages are kept within the brain, while others are relayed through the spine and across the body’s vast network of nerves to distant extremities. To do this, the central nervous system relies on billions of neurons (nerve cells).

Main Parts of the Brain and Their Functions

At a high level, the brain can be divided into the cerebrum, brainstem and cerebellum.

Cerebrum

The cerebrum (front of brain) comprises gray matter (the cerebral cortex) and white matter at its center. The largest part of the brain, the cerebrum initiates and coordinates movement and regulates temperature. Other areas of the cerebrum enable speech, judgment, thinking and reasoning, problem-solving, emotions and learning. Other functions relate to vision, hearing, touch and other senses.

Cerebral Cortex

Cortex is Latin for “bark,” and describes the outer gray matter covering of the cerebrum. The cortex has a large surface area due to its folds, and comprises about half of the brain’s weight.

The cerebral cortex is divided into two halves, or hemispheres. It is covered with ridges (gyri) and folds (sulci). The two halves join at a large, deep sulcus (the interhemispheric fissure, AKA the medial longitudinal fissure) that runs from the front of the head to the back. The right hemisphere controls the left side of the body, and the left half controls the right side of the body. The two halves communicate with one another through a large, C-shaped structure of white matter and nerve pathways called the corpus callosum. The corpus callosum is in the center of the cerebrum.

Brainstem

The brainstem (middle of brain) connects the cerebrum with the spinal cord. The brainstem includes the midbrain, the pons and the medulla.

The spinal cord extends from the bottom of the medulla and through a large opening in the bottom of the skull. Supported by the vertebrae, the spinal cord carries messages to and from the brain and the rest of the body.

Cerebellum

The cerebellum (“little brain”) is a fist-sized portion of the brain located at the back of the head, below the temporal and occipital lobes and above the brainstem. Like the cerebral cortex, it has two hemispheres. The outer portion contains neurons, and the inner area communicates with the cerebral cortex. Its function is to coordinate voluntary muscle movements and to maintain posture, balance and equilibrium. New studies are exploring the cerebellum’s roles in thought, emotions and social behavior, as well as its possible involvement in addiction, autism and schizophrenia.

Brain Coverings: Meninges

Three layers of protective covering called meninges surround the brain and the spinal cord.

Lobes of the Brain and What They Control

Each brain hemisphere (parts of the cerebrum) has four sections, called lobes: frontal, parietal, temporal and occipital. Each lobe controls specific functions.

Deeper Structures Within the Brain

Pituitary Gland

Sometimes called the “master gland,” the pituitary gland is a pea-sized structure found deep in the brain behind the bridge of the nose. The pituitary gland governs the function of other glands in the body, regulating the flow of hormones from the thyroid, adrenals, ovaries and testicles. It receives chemical signals from the hypothalamus through its stalk and blood supply.

Hypothalamus

The hypothalamus is located above the pituitary gland and sends it chemical messages that control its function. It regulates body temperature, synchronizes sleep patterns, controls hunger and thirst and also plays a role in some aspects of memory and emotion.

Amygdala

Small, almond-shaped structures, an amygdala is located under each half (hemisphere) of the brain. Included in the limbic system, the amygdalae regulate emotion and memory and are associated with the brain’s reward system, stress, and the “fight or flight” response when someone perceives a threat.

Hippocampus

A curved seahorse-shaped organ on the underside of each temporal lobe, the hippocampus is part of a larger structure called the hippocampal formation. It supports memory, learning, navigation and perception of space. It receives information from the cerebral cortex and may play a role in Alzheimer’s disease.

Pineal Gland

The pineal gland is located deep in the brain and attached by a stalk to the top of the third ventricle. The pineal gland responds to light and dark and secretes melatonin, which regulates circadian rhythms and the sleep-wake cycle.

Ventricles and Cerebrospinal Fluid

Deep in the brain are four open areas with passageways between them. They also open into the central spinal canal and the area beneath arachnoid layer of the meninges.

The ventricles manufacture cerebrospinal fluid, or CSF, a watery fluid that circulates in and around the ventricles and the spinal cord, and between the meninges. CSF surrounds and cushions the spinal cord and brain, washes out waste and impurities, and delivers nutrients.

Blood Supply to the Brain

Two sets of blood vessels supply blood and oxygen to the brain: the vertebral arteries and the carotid arteries.

The external carotid arteries extend up the sides of your neck, and are where you can feel your pulse when you touch the area with your fingertips. The internal carotid arteries branch into the skull and circulate blood to the front part of the brain.

The vertebral arteries follow the spinal column into the skull, where they join together at the brainstem and form the basilar artery, which supplies blood to the rear portions of the brain.

The circle of Willis, a loop of blood vessels near the bottom of the brain that connects major arteries, circulates blood from the front of the brain to the back and helps the arterial systems communicate with one another.

Cranial Nerves

Inside the cranium (the dome of the skull), there are 12 nerves, called cranial nerves:

The first two nerves originate in the cerebrum, and the remaining 10 cranial nerves emerge from the brainstem, which has three parts: the midbrain, the pons and the medulla.