Perception and Reality
Things Are Not Always
As They Seem...
Brain Basics
Facts and Misconceptions
Brain Basics
Overview
Brain Facts Discussion and Questions
General Facts
Parts of the Brain
Functions
Brain Misconceptions Discussion
Properties of Neurons Discussion
Brain Facts
The adult human brain is about 4 to 5 pounds. A baby’s
brain weighs about 1.5 pounds.
However, a baby’s body weighs about 15-30 times
smaller than an adult’s body. So a baby’s brain is 6
times bigger compared to its body weight!!!
(that is why babies have huge heads compared to their
bodies)
Human brain has over 100 billion! neurons (a type of
brain cell); that’s about 20 times the total number of
people in the world.
Neurons require a lot of energy: Your brain uses over
half of all the energy in your body.
Brain Lobes
The Cerebral Cortex (wrinkled
outside part of the brain) is
arbitrarily divided into 4
lobes based upon the things
that scientists think they do
The occipital lobe processes
the visual information from
your eyes
The frontal lobe makes highlevel decisions, plans
movements, coordinates
speech, and has a large role
in determining personality
and morality (Phineas Gage)
Brain Lobes
The parietal lobe processes
you sense of touch,
processes your concept
of spatial relationships
(where things are)
The temporal lobe helps
identify things (what
things are), helps you
remember things, and
processes sounds
(hearing)
Other Brain Parts
The Cerebellum has as
many neurons as the
entire cerebral cortex!
Its main role it to
coordinate movements
or brain activities (make
sure their timing is
right)
The Brainstem controls
the body processes that
you don’t have to think
about (like your heart
beat)
Brain Misconceptions
10%
Do people only use 10% of their brain?
No.
Different parts of your brain do different
things. So not all of your brain needs to be
doing something all of the time. However,
using modern technology we have shown
almost every area of the brain active during
some task.
For many hard tasks, a large percentage of
your brain may be active at one time.
Brain Misconceptions
Wrinkles
Why are there wrinkles in the brain? Do more wrinkles
appear when you learn something new?
No.
Your cerebral cortex is essentially a flat sheet (like a
large sheet of paper) that it has to fit in your skull
(which is like a cup)… A crumpled up sheet of paper
fits in a cup easier than an unfolded one.
Most scientists think that new learning is changed
connections between neurons (brain cells; similar to
different wiring in a computer).
Brain Misconceptions
Gender and Brain Size
Do boys have bigger brains and are they smarter than
girls or the opposite?
(1) Men on average actually do have larger brains
than women (just like they have bigger bodies on
average). But, elephants have much bigger brains
than humans (4 times as heavy) and cats are about 45
times smaller.
(2) A bigger brain does not mean you are smarter.
Men and women have the same intelligence level on
average (although there is some evidence that each
may be slightly better at specific tasks). Two people
with the biggest and one of the smallest brains ever
found both belong to professional writers!
Brain Misconceptions
Computers (1)
Is the brain like the CPU of a computer?
Not really.
Computers are made of metal and use electricity to
process information. Brains are made of organic cells
and use a mix of electrical signals and chemicals to
process information.
If one part of a computer breaks it can do almost
nothing. If one part of your brain gets damaged only
certain things are hard to do and it can sometimes
gradually repair itself.
Brain Misconceptions
Computers (2)
Are humans smarter than computers or computers
smarter than people?
Neither, they work in different ways.
Computers are currently all programmed to do a
specific task by people who give them specific
instructions about how to do it. Computers are much
faster at doing many of these things.
Currently, computers are not able to do things they
are not specifically told how to do. This is changing
as people figure out ways to make computers learn to
do new tasks on their own.
Humans, however, are very good at figuring out creative
ways to do things on their own.
Brain Misconceptions
Drug Addiction (1)
If you are careful you won’t get addicted to drugs, right?
Examples of addictive Drugs – all types of Cocaine (crack);
Heroin; Opium; Ecstasy; …
Mostly affect the parts of your brain that process reward
(pleasure) information or help you manage pain: when they
work normally, they help you in emergencies or to encourage
you to become addicted to good behavior (like eating
nutritious food) to make you want to do it again and again
The problem: these drugs either overuse or kill off cells in these
systems so they work too strongly or eventually not enough…
Some brain areas cause a little addiction even when working
correctly; drugs cause these areas to work way too much…
Brain Misconceptions
Drug Addiction (2)
Do drugs really hurt you long-term?
Yes. Long-term overuse of the systems of reward through drugs:
Strong addiction to the drugs.
Leads to less sense of reward for other activities that are
actually good for you so you stop doing them.
As cells die from overuse (or become habituated), you need
more and more drugs to get the same high.
Then when you are not doing drugs you feel worse than you
did before you started.
In other words: Drugs damage your brain more the longer and
more you do them (much of which will never recover).
They trick your brain into thinking life is great when you
are on them and much worse when you are not (even
compared to before you started) so they are harder to stop.
Neurons
These brain cells share most of the properties of
cells in every living organism.
They have a nucleus; and a membrane through
which they exchange things with the blood.
They require nutrients and energy (from the
blood).
They must get rid of waste and heat (to the
blood).
They require time to perform any of their
functions and also time to reset, so they can
perform the function again.
Dendrites, Cell Body, Axon
A neuron is made up of 3 parts (diagram in next slide):
The dendrites (sometimes called a dendritic tree) get
the chemical inputs from other neurons
The axon is the output mechanism that sends messages
to other neurons
The cell body does all of the processing of the
information received from the dendrite and
determines what message should be sent out through
the axon
The connection between one cell (from an axon) and
another (usually to a dendrite) is called a synapse
Neuron Diagram
Dendrites
Cell Body
Axon
Synapse
Similarities with Other Cells
These brain cells share most of the properties of
the cells in every living organism.
They have a nucleus; and a membrane through
which they exchange things with the blood.
They require nutrients and energy (from the
blood).
They must get rid of waste and heat (to the
blood).
They require time to perform any of their
functions and also time to reset, so they can
perform the function again.
Differences
There are some differences however:
Neurons are extremely energy expensive cells;
over a third (and sometimes more than a half)
of all our energy goes to our brains.
Because of this, neurons create a lot of heat.
Neurons require special chemical nutrients
(most cells just need glucose, water,…).
Neurons communicate with other cells (most
cells do not).