The Brain | Part 13 | Discovery Channel Body Atlas

Summary

This script delves into the marvel of the human brain, the organ of consciousness and thought, highlighting its evolution, complexity, and functions. It explores how the brain enables learning, perception, and abstract thinking, shaping our experiences and knowledge. From the intricate network of neurons to the brain's growth and development, the script paints a picture of the brain as a pinnacle of evolution, a mysterious yet powerful organ that underpins our very existence.

Takeaways

• 🧠 The human brain is an organ of immense complexity, controlling every move we make and enabling us to learn from birth.
• 🤔 It is the pinnacle of evolution, the only object aware of its own existence, and the center of intelligence with senses that pick out sounds and touches.
• 🔬 The brain's power lies in its billions of microscopic nerve cells, which create an intricate network of connections, far more complex than a computer chip.
• 🚀 Humans dominate the world not by strength or speed but by the development of the brain, which allows us to think in abstract symbols and accumulate knowledge.
• 💡 The brain requires a continuous supply of energy, with over a pint of blood flowing through it every minute, highlighting its sensitivity to oxygen deprivation.
• 🌱 The nervous system is one of the first parts of the body to form, with the brain developing rapidly in the womb, producing a quarter of a million nerves every minute.
• 👶 The wiring of the brain is shaped by experience, with the brain growing rapidly as it coordinates the body and learns skills like language through repetition and reinforcement.
• 🧬 The brain's structure changes as we learn, with the process of relearning and skill acquisition actually rewiring the brain, making humans remarkably flexible learners.
• 🧬📈 The front brain, which has reached its maximum complexity in humans, is responsible for our thinking and decision-making processes.
• 🦈🐠🐦🐇 Despite its complexity, the human brain retains its ancient fishy brain for basic life functions, with the cerebellum playing a key role in balance.
• 🧬🧠 The evolution of the human brain is marked by an increase in size and complexity, with the modern human brain reaching its present size 130,000 years ago but taking longer to reach mental capacity.
• 🧠🌐 The brain's cortex, with its crumpled surface, allows for a large surface area to be packed into a small volume, enhancing our thinking power beyond other animals.
• 🤲 The brain devotes a disproportionate amount of nerve cells to sensitive and finely controlled body parts, such as the lips and hands, reflecting their importance in expression and manipulation.
• 👁️👂👃 Our senses are deeply interconnected, with each sense stimulating specific regions of the brain and contributing to our seamless perception of the world.
• 🗣️ Language has a profound impact on the way we think, organizing our thoughts and enabling us to communicate complex ideas and emotions.
• 🔄 The brain's ability to learn and remember involves the formation of new connections, with memories becoming more ingrained through repetition.

Q & A

What is the human brain's role in our ability to learn?

The human brain, with its 14 billion cells, forms a complex network that enables us to learn from the moment we're born, providing insight and creativity.

How does the brain's structure contribute to its function as the center of intelligence?

The brain's structure, with its billions of microscopic nerve cells and trillions of connections, allows for complex intelligence operations, processing sensory information and enabling abstract thinking.

What is the significance of the brain's blood supply in maintaining its function?

The brain requires a continuous supply of oxygen and sugar for energy. Over a pint of blood flows through the brain every minute, and a lack of oxygen can lead to rapid nerve cell death and permanent damage.

How does the brain's development during early life influence our cognitive abilities?

The brain's development in the womb and early childhood is crucial for cognitive abilities. It produces a quarter of a million nerves every minute during the first four months, shaping the wiring of the brain through experience and learning.

What is the role of the cerebellum in the body's balance and coordination?

The cerebellum, a primitive part of the brain, is responsible for maintaining balance and coordinating movement. Its complexity in humans may be due to the challenges of balancing on two legs.

How does the brain's structure adapt as we learn new skills or knowledge?

As we learn, the brain rewires itself by strengthening the connections used for new knowledge or skills. This process of reconnection makes humans remarkably flexible in learning.

What evolutionary changes in the brain have contributed to human intelligence?

The front brain has evolved to be the largest part, contributing to higher intelligence. Over millions of years, the human brain has increased in size and complexity, enhancing cognitive abilities.

How does the brain process sensory information from different parts of the body?

The brain processes sensory information through specific regions of the cortex dedicated to different senses. It integrates these responses to create a seamless perception of the world.

What is the significance of the brain's two hemispheres in interpreting the world?

The two hemispheres of the brain interpret the world differently; the left hemisphere thinks in words, while the right hemisphere thinks in images and feelings, exchanging information through a dense band at the base of the brain.

How does the brain's sensory cortex represent different parts of the body in terms of sensitivity?

The sensory cortex represents different parts of the body based on their sensitivity. Highly sensitive areas like the lips and hands are represented as larger in the brain's view, indicating their importance in sensation and control.

What is the process of memory formation and retrieval in the brain?

Memory formation involves short-term memory and long-term memory. The brain selectively stores important information and forges new connections between nerves. Retrieval of memories is still a mystery, but it involves the reactivation of these dispersed connections.

Outlines

00:00

🧠 The Marvel of the Human Brain

This paragraph delves into the complexity and function of the human brain, highlighting its role as the control center for our actions and thoughts. It underscores the brain's capacity to learn and adapt from birth, facilitated by its 14 billion cells and intricate network. The brain is portrayed as an organ of immense power, enabling us to perceive our environment through our senses and process information through the spinal cord. The script also touches on the brain's evolution, its energy requirements, and the significance of its microscopic nerve cells, which, through electrical signals, allow for abstract thinking and knowledge accumulation across generations.

05:02

🌱 The Development and Flexibility of the Nervous System

The second paragraph explores the development of the nervous system, starting from its initial formation three weeks after fertilization. It details the rapid growth of the brain and the production of nerves, emphasizing the brain's ability to create new pathways and adapt through learning. The paragraph also discusses the importance of experience in shaping the brain's connections and the remarkable plasticity of the human brain, which allows for the acquisition of new skills and knowledge. The evolution of the brain from our earliest ancestors to modern humans is briefly traced, illustrating the enlargement of the front brain and its significance in cognitive advancement.

10:04

🦴 The Ancient yet Essential Brain Functions

This section examines the ancient parts of the brain that perform vital functions, such as maintaining heartbeat and respiration, and the cerebellum's role in balance. It points out that despite the complexity of the human brain, we still possess these primitive regions that contribute to our basic survival. The paragraph also discusses the evolution of the brain's size and complexity, from the early Australopithecus to Homo erectus, and the significance of the brain's geometry in accommodating the increasing number of nerve cells without enlarging the skull. The unique capabilities of the human cortex in decision-making, interpretation, and understanding are highlighted.

15:07

🤲 The Brain's Control Over Movement and Sensation

The fourth paragraph focuses on the brain's control over the body's movements and sensations. It explains how the brain's hemispheres are responsible for opposite sides of the body and how the sensory cortex processes different types of sensory input. The paragraph describes the brain's representation of the body, with highly sensitive areas such as the lips and hands receiving a disproportionate amount of nerve cells. It also discusses the development of motor skills, starting with facial expressions and progressing to fine motor control in the hands, which has been crucial for human evolution and cultural achievements.

20:13

🌐 The Integration of Senses and Memory Formation

The final paragraph discusses the integration of our senses and the brain's role in memory formation. It describes how the senses work together to create a cohesive perception of the world, despite our limited understanding of the underlying neural pathways. The paragraph also delves into the process of memory, from short-term to long-term, and how repetition strengthens these memories by forming new neural connections. The discussion concludes with the brain's remarkable capabilities, its role in language, and its potential for self-improvement, emphasizing the brain as a powerful and mysterious organ that drives human intelligence and consciousness.

Keywords

💡Brain

The brain is the central organ of the human nervous system, playing a pivotal role in the video's theme as it is the organ that enables cognition, learning, and consciousness. Defined as the 'pinnacle of evolution' in the script, the brain is portrayed as the key to human success, allowing us to think abstractly and build knowledge across generations. The script also delves into the brain's physical attributes, such as its complex network of neurons and its evolution from our ancestors.

💡Nerve Cells

Nerve cells, or neurons, are the fundamental units of the nervous system, responsible for transmitting information throughout the body. The script highlights that the brain contains billions of these microscopic cells, which, through electrical signals, facilitate thought and learning. The comparison of neurons to transistors in a computer chip illustrates their role in processing information, emphasizing the brain's complexity and computational power.

💡Consciousness

Consciousness is the state of awareness, arousal, and attention, and it is deeply intertwined with the brain's function. In the script, consciousness is described as a product of the brain, suggesting that it is the brain's activity that gives rise to our sense of self and awareness of our existence. The concept is integral to the video's exploration of what makes humans unique and capable of introspection.

💡Evolution

Evolution is the process by which species change over time, and it is a central theme in the video's narrative about the development of the human brain. The script discusses how the brain has evolved from a simple structure in early ancestors to the complex organ it is today, enabling advanced cognitive functions. The evolution of the brain is illustrated through changes in skull size and the development of new capabilities, such as tool-making and language.

💡Neural Connections

Neural connections refer to the synaptic links between neurons, which are crucial for communication within the brain. The script emphasizes the staggering number of connections in the human brain, outnumbering the stars in the Milky Way, highlighting the organ's complexity. These connections are also portrayed as dynamic, capable of forming new pathways as we learn and adapt, which is central to the brain's plasticity and our ability to acquire new skills and knowledge.

💡Cortex

The cortex, or cerebral cortex, is the outer layer of the brain where most higher brain functions are carried out. The script describes the cortex as a crumpled surface that allows for a large surface area within a confined volume, contributing to the brain's advanced cognitive capabilities. It is where decisions are made, opinions are formed, and sensory information is interpreted, making it a key region in understanding human intelligence.

💡Hemispheres

The brain is divided into two hemispheres, each responsible for different aspects of cognition and sensory processing. The script explains that the left hemisphere is associated with verbal thinking, while the right hemisphere is linked to visual and emotional thinking. This distinction is crucial for understanding how the brain processes information and how the two halves communicate and integrate their functions.

💡Sensory Cortex

The sensory cortex is the area of the brain where sensory information from the body is processed. The script uses the sensory cortex to illustrate how the brain perceives and interprets different parts of the body, with highly sensitive areas like the lips and hands receiving a disproportionate amount of neural representation. This concept is vital for understanding how our senses contribute to our perception of the world.

💡Memory

Memory is the faculty by which the mind stores and retrieves information. The script discusses both short-term and long-term memory, explaining how the brain selectively stores information it deems important. The process of memory formation is linked to the physical changes in the brain, such as the creation of new neural connections, which is a fundamental aspect of learning and knowledge retention.

💡Language

Language is a system of communication using words and grammar, and it is deeply connected to the brain's cognitive functions. The script highlights how language organizes thoughts, facilitates learning, and influences the way we think. It also touches on the brain regions involved in speech production, emphasizing the interplay between neural activity and linguistic expression.

💡Cerebellum

The cerebellum is a region of the brain that plays a key role in motor control, coordination, and balance. The script describes it as the most complex cerebellum in the animal kingdom, suggesting its importance for human bipedal locomotion. The cerebellum's function is integral to the video's exploration of the brain's role in physical movement and coordination.

Highlights

The human brain controls 14 billion cells, forming an almost infinitely complex network.

Brain's tranquil folds are the busiest organ, providing insight and creativity.

The brain is the pinnacle of evolution and the only object aware of its own existence.

Brain's intelligence is centered around sensory inputs from eyes, ears, and skin.

The spinal cord acts as the body's information superhighway, routing sensory signals.

The brain is key to human success, enabling abstract thinking and knowledge accumulation.

Brain's 3 pounds of tissue contain billions of microscopic nerve cells for complex operations.

10 trillion brain connections outnumber the stars in the Milky Way by a hundred times.

Brain requires a continuous supply of oxygen and sugar for its active nerve cells.

Brain's energy supply is 10 watts, a fraction of a computer's needs.

Nerve cells can create new pathways, unlike programmed electrical currents in computers.

The nervous system begins forming just 3 weeks after human egg fertilization.

Brain's structure changes as we learn, rewiring itself with new knowledge and skills.

The front brain's complexity in humans is unmatched, facilitating abstract thought.

Primitive brain regions like the cerebellum maintain vital functions and balance.

Evolution of the human brain is marked by changes in skull size and complexity.

The human brain's cortex, with its crumpled surface, allows for advanced cognitive functions.

The brain's two hemispheres interpret the world differently, with the left thinking in words and the right in images.

The brain selectively stores information, prioritizing what seems important for survival.

Memories are ingrained through repetition, changing the brain's structure.

The human brain is a powerful and mysterious organ, with scientists still exploring its full capabilities.

Transcripts

it controls every move we make it's 14

billion cells connect a network of

almost infinite complexity which enables

us to learn from the moment we're born

these tranquil folds are the busiest

organ in the body constantly providing

us with insight and creativity

probe the secrets of our mind as we

explore the human brain next on body

atlas

[Music]

I think therefore I am this is the home

of all human thought and of our

consciousness the human brain is the

pinnacle of evolution the only object

aware of its own existence it's also the

center of a complex intelligence

gathering operation that employs the

clear window of the eyes senses to pick

out the sounds and sweet airs that

surround us organs of touch crowding

into the sensitive folds of the lips and

every inch of the skin they alert us to

a warm wind or the chill of snow the

lightest touch or a stab of pain these

signals are routed along the bodies

information superhighway the spinal cord

this bundle of delicate nerves is

protected by a spiky suit of armor the

backbone

[Music]

it leads upwards to the bony helmet of

the skull encasing one small organ that

can encompass the whole world outside

[Music]

Brian and his classmates take this jewel

in their crowns for granted

unlike the bodies other organs we can't

easily feel or monitor the brains

ceaseless activity but it's the key to

human success we've come to dominate the

world not by strength or speed but by

the development of this one special

organ we can think in abstract symbols

like language and math and build up

knowledge from generation to generation

the power of the brain isn't evident at

first sight looking like an oversized

walnut it's 3 pounds of soft watery

tissue the brain secret lies in its

billions of microscopic nerve cells when

we think minut electrical signals flash

between these nerves it's similar to the

electric currents that flow between the

tiny transistors in the computer chip

when it makes a calculation but the

network of nerves is far more complex

the 10 trillion connections in one brain

outnumber the stars in the Milky Way a

hundred times over the active nerve

cells need a generous supply of energy

this network of blood vessels brings in

oxygen and sugar the brain's fuel over a

pint of blood flows through the brain

every minute

and a continuous supply of blood is

essential nerves die rapidly when oxygen

is cut off after just a few seconds some

cells begin to shut down we lose

consciousness after a couple of minutes

the brain suffers permanent damage

[Music]

Bryan's brain requires an energy supply

of 10 watts only a fraction of the

computer's needs like the Machine his

nerve center is wired into a wider

Network electrical energy constantly

conveys signals along the spinal cord to

and from the brain but in close-up nerve

cells are very different from electrical

wires there are many gaps for the

signals to jump providing thousands of

alternative routes and living nerve

cells can link up to their neighbors

creating yet more new pathways

unlike the programmed root of electric

currents in the computer the nervous

system is one of the first parts of the

body to form only 3 weeks after a human

egg has been fertilized some of the

cells develop into a distinct swelling

which becomes the brain and spinal cord

[Music]

over the next two months the nervous

system develops at an amazing speed

during this time the brain turns out a

quarter of a million nerves every single

minute these cells move through the

tissues of the body to their final

destinations here a new arrival is

putting out feelers to connect with its

neighbors over the first four months of

the womb the baby's brain produces all

the nerve cells it'll ever have

[Music]

at the same time

bones highlighted in red start to form

they protect the vulnerable network of

nerves

[Music]

the top of the skull is made of eight

separate bones allowing the brain to

grow inside five months before birth 14

billion brain cells are in place yet

even at birth vital connections between

these cells are missing compared to

other animals the newborn human brain

has a long way to go to reach its full

potential the wiring of the brain is

shaped by experience as parents and

teachers pass on thousands of years of

accumulated knowledge it's expanding

network of connections makes the brain

grow rapidly with signals from the eyes

and ears hands and feet the brain begins

to coordinate the young body by

repeating its successes a child learns

hand-eye coordination the skill of

balancing on two legs and even something

as complicated as language by the age of

two some children can speak 2,000 words

as we learn we actually change the

structure of the brain all parts of the

brain are connected by these bundles of

nerve fibers Criss crossing the interior

like telephone lines

each time we repeat an action or a word

the connection we're using becomes

stronger so as we achieve new knowledge

and skills we literally rewire our

brains these reconnections make humans

remarkably flexible in what we can learn

it's one reason for our success as a

species the rewiring takes place within

the front brain it's the part of our

brain that thinks the front brain has

reached its maximum complexity in humans

after billions of years of evolution

the brain of our earliest ancestors the

fish has only a very small front region

the fringe on the left the main bulge

deals with sight the fish's most

important sense the front brain grew

rapidly as our ancestors became

amphibians by the time reptiles evolved

it was the largest part of the brain in

a bird the front brain has enlarged

further a bird is smarter than a reptile

in the first mammals the growth of the

front brain and intelligence continued

until in humans the crinkled surface of

the front brain seems to have taken over

entirely but hidden inside and below we

still have our ancient fishy brain

carrying out its age-old functions these

nether regions of the brain keep our

hearts beating and our lungs breathing

the cauliflower shaped cerebellum keeps

our bodies in balance the human

cerebellum is the most complex in the

animal kingdom possibly because it's

more difficult to balance on two legs

than on four

this early part of the brain has a

primitive beauty all its own

[Music]

without the cerebellum we'd have to

concentrate on standing upright and

taking every step from its primitive

base upwards the human brain has

successive layers of intricate

connections and staggering complexity in

these layers is hidden everything that

makes us individuals emotions memories

aspirations and thoughts the human brain

has reached its present complexity in

size in only five million years since

the human lineage split from the

chimpanzee the story of the brains

evolution is revealed by changes in the

skull a modern chimpanzee has a brain

only slightly smaller than one of our

possible ancestors Australopithecus

africanus who lived 3 million years ago

2 million years ago a larger brained

early human emerged these people made

the first tools

[Music]

dating back half a million years this

human skull housed a brain twice as

large as the early Australopithecus Homo

erectus had mastered the art of using

fire the human brain reached its present

size a hundred and thirty thousand years

ago but it took another hundred thousand

years to reach a mental capacity similar

to ours a child from 35,000 years ago

could easily learn all the skills needed

to survive in present-day society the

human characteristics that evolve them

self-expression and curiosity are still

the cornerstones of society today the

number of nerve cells in the brain has

multiplied immensely over the past few

million years the brain was in danger of

outgrowing the skull but it was saved by

a clever piece of geometry the cells we

use to think lie on the surface of the

brain in a layer just 1/8 of an inch

thick the cortex and a large surface can

be stuffed into a small volume by

crumpling it up like a sheet of paper

the cortex has crumpled into fissures

and grooves if we smoothed out the

crinkles the cortex would be the size of

a pillowcase

with these intricate folds we far

outdistanced the thinking power of even

the largest animal brain the nerve cells

in the cortex do everything that unique

to humans to make decisions to voice

opinions to interpret what we see and

hear and to understand it the crumpled

cortex forms two distinct hemispheres

each filled with bundles of nerves the

two halves have different ways of

interpreting the world the left

hemisphere thinks in words while the

right half thinks in images and feelings

the nerves exchange information through

a dense band at the base of the brain

every point in the right hemisphere is

connected to an exact mirror image point

in the left hemisphere

if the word water appears here in the

left hemisphere then just here the right

hemisphere has an image of water to

prevent any argument within the brain

one hemisphere almost always the left

makes the ultimate decisions when it

comes to controlling the muscles each

hemisphere is responsible for one side

of the body all the way from the feet

and legs to the hands and eyes but the

lines of command cross over the left

side of the body is connected to the

brains right hemisphere while sensations

from the right side of your body

and up in the left hemisphere the most

sensitive regions command a

disproportionate number of nerve cells

in the brains feeling Center called the

sensory cortex

[Music]

this weird figure shows how your brain

feels your body to be highly sensitive

parts loom large in the brains view of

the body the lips look huge because

they're extremely sensitive and ideal

for displaying our feelings

[Music]

children instinctively use their lips to

explore the world around them the boss

stimulates the nerves in his lips

sending signals to this very specific

part of the brain a different part of

the sensory cortex lights up when you

touch something with your right index

finger the hand is packed with nerve

endings so we feel it to be much larger

than life the thumb is biggest of all it

can discriminate the finest details by

touch the entire back stimulates fewer

nerve cells in the sensory cortex than

the palm of your hand

[Music]

a second figure shows how much of the

brain is devoted to controlling our

bodies

his largest parts have many nerve cells

in charge of finely tuned muscles the -

distorted figures have much in common

parts of the body sensitive to touch

generally need the finest control from

birth our nerves can feel sensations but

it takes time and patience to control

our muscles properly among the first we

master are the facial muscles a baby can

express emotions with a smile or a frown

from a very early age our facial

expressions acquire more finesse as our

muscles and nervous system become more

mature the expressive lips need fine

control to convey speech and emotions in

the brains view they are enormous the

hands are packed with precision muscles

the huge amount of brain devoted to the

hand has been vital for our evolution

from our clumsy ancestors and it's led

to some of our greatest cultural

achievements to monitor our muscles we

rely on our vigilant sense organs each

is connected to its own region of the

brains cortex

the eyes send signals to the back of the

brain along nerves that cross over on

the way

where we see the world is strangely

farthest from the eyes themselves when

you see something electrical signals

race along these pale nerve bundles they

carry coded messages through the brains

massive hemispheres to the back of the

cortex

this scan shows electrical activity in

the part of the brain where the messages

are received

[Music]

the ear keeps us in touch with every

sound and with messages from our fellow

human beings sounds are amplified and

detected by a natural microphone it

signals more sensibly are analyzed in a

region of the brain right next to the

ear smells are conveyed by invisible

molecules to the back of the nose they

trigger nerves that fire straight into

the depths of the brain where our

emotions reside

that's why smells can trigger long-lost

feelings and other memories hear a sniff

of perfume lights up several parts of

the brain the visual region at the lower

right is recalling of you associated

with the smell

[Music]

the unconscious pathways that link our

senses are still largely unexplored and

we don't understand how the cortex ties

together it's scattered responses to our

different senses to create a seamless

image of the world around us most things

we do involve almost every part of the

brain even something apparently as

simple as answering a question yes we

must hear the words understand them draw

on our memories and then voice the

answer because it reinforces particular

pathways through the brain language has

molded the very way we think this area

organizes our thoughts according to the

rules of grammar it sends signals to the

region which coordinates our breathing

vocal cords tongue and lips to allow us

to speak language helps us to learn new

facts and new ideas but we can't recall

everything we were taught at high school

the brain is selectively choosing what

seems to be important and it stores

information in two stages first is

short-term memory

Samos hear a new word and you can recall

it for a few seconds but it will quickly

fade

unless it's filed in the long term

memory which like choose Desperados

quarry fraud new school versus to retain

what you've learned the brain must build

up permanent new connections between its

nerves the actual structure of the brain

changes subtly each time we commit a new

fad to our long-term memory

new links are forged throughout the

brain but it's still a mystery how we

can recall these dispersed memories at

will

[Music]

with constant repetition memories become

more deeply ingrained the brain can

teach itself by repeating words and

facts mentally remarkably the technique

also works for physical skills the human

brain is our most wonderful and our most

mysterious organ scientists have yet to

learn the function of every fold

increase and how this mass of nerve

cells creates intelligence consciousness

and self-awareness a computer that can

think let alone be aware of itself is

still far off in the realms of science

fiction yet each one of us contains a

far more powerful computer than any

space-age instrument the human brain has

the ingenuity to take us to the farthest

corners of the earth and beyond its

mental reach knows no limit

with our flexible brain we can look

beyond our own world and contemplate the

infinite

[Music]