Transcript The Teenage Brain - Model High School

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.
The Early Human Brain
• Embryonic Brain
The Brain at Birth
Brain Development
Embryonic to 6 Mos.
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.
Fissures (deep grooves)
divide the cerebrum into lobes
Frontal lobe
Parietal lobe
Frontal
association
area
Taste
Somatosensory
association
area
Reading
Hearing
Speech
Smell
Visual
association
area
Auditory
association
area
Vision
Temporal lobe
Occipital lobe
If Christopher is in a car accident and due to
brain damage loses his sight, which lobe of
the brain were probably damaged?
When you go to the refrigerator and reach for a
carton of milk, which lobes of the brain are
you using?
When you are listening to music on earphones,
which lobe of the brain are you using?
When an Olympic gymnast does a flip on the
balance beam, which lobes of the brain is she
using?
Regions of the Brain
Cerebral hemispheres
 Diencephalon

Brain stem
 Cerebellum

Surface is made of ridges (gyri) and grooves
(sulci) purpose: to increase surface area
Figure 7.12b
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).
Specialized Areas of the
Cerebrum
Somatic sensory area – receives
impulses
from
the
body’s
sensory
Interpretation
areas
of
the
cerebrum
Broca’s area – involved in our ability to
receptors
(audio,
visual,
olfactory,
and
Speech/language
region
speak
taste)
Figure 7.13c
Motor Areas of the Cerebral Cortex
Primary motor area – sends impulses to
skeletal muscles
Figure 7.14
Layers of the
Cerebrum

Gray matter
› Outer layer
› Composed mostly of neuron cell bodies
White matter
› Fiber tracts inside the gray matter
› Example: corpus callosum connects
hemispheres
Figure 7.13a
Diencephalon
Sits on top of the brain stem
 Enclosed by the cerebral hemispheres

•Thalamus
•Hypothalamus
•Epithalamus
Thalamus
Surrounds the third ventricle
 The relay station for sensory impulses
 Transfers impulses to the correct part of
the cortex for localization and
interpretation

Hypothalamus
 Under
the thalamus
 Important autonomic
nervous system center
› Helps regulate body
temperature
› Controls water balance
› Regulates metabolism
An important part of the limbic system
(emotions)
 The pituitary gland is attached to the
hypothalamus

Epithalamus
Forms the roof of the third ventricle
 Houses the pineal body (an endocrine
gland)
 Includes the choroid plexus – forms
cerebrospinal fluid

Brain Stem
Attaches to the
spinal cord
 Parts of the brain
stem

› Midbrain
› Pons
› Medulla oblongata
Midbrain
Mostly composed of
tracts of nerve fibers
 Has two bulging fiber
tracts –
cerebral peduncles
 Has four rounded
protrusions –
corpora quadrigemina

› Reflex centers for vision
and hearing
Pons
The bulging center part of the brain stem
 Mostly composed of fiber tracts
 Includes nuclei involved in the control of
breathing

Medulla Oblongata



The lowest part of the brain stem
Merges into the spinal cord
Contains important control centers
› Heart rate control
› Blood pressure regulation
› Breathing
› Swallowing
› Vomiting
Random Brain Facts
BRAIN FACTS

Let’s do some mythbusting.
Myths – TRUE OR
FALSE?

We use 10% of brain
FALSE!

We use all of our brain.
Under PET scans and CAT
scans, different areas of
the brain are used, but we
use our whole brain.
The effect of extreme deprivation in
infancy: This child suffers from emotional
and cognitive problems.
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.
Myth?

As we age, we lose our brain cells.
FALSE!

The brain can continue to learn and
“make connections” until death.
Myth ?

Every drink kills 10,000 cells
FALSE
Every drink does not kill
10,000 cells.
 Scare tactic.
 Drinking does affect
development – especially
fetus and teenagers.

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.
Does Size Matter?
What is the biggest organ
in the body?
The Skin
Skin – 6 lbs
 Brain, 2.75-3 lbs

There is no correlation
between brain size and
ability.
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!
Random Brain Facts
• We’ve learned more about the
brain in last 20 yrs than all time
previous to that
• No two brains are identical
• Brain is mostly water (78%), fat
(10%), and protein (8%)
• Living brain is so soft it can be
cut w/ butter knife
Random Brain Facts
• The adult human brain weighs
about 3 pounds (1,300-1,400 gm)
– Elephant brains = 6,000gm
– Cat brains = 30 gm
• Brain is ~2% of body weight, but
consumes ~20% of body’s energy
• Total surface area of cerebral cortex
= ~2.5 sq ft
• Bigger brains are not necessarily
better
• Einstein’s was average size
Random Brain Facts
• Human brain has ~100,000,000,000
neurons
• If all neurons were stretched end to
end, would reach to moon and back
• Every second, brain receives 100
million messages from the senses
• ¾ of body’s neurons are in brain
• On day you are born, all brain cells
are in place
– They’re just immature – still developing
• Explains why don’t have memories until ~3-4 y.o.
– Will not regenerate – this is all you get
• (Recent research is challenging this idea…)
Random Brain Facts
• ~10 trillion pieces of information in
the brain
• There are 1,000 – 10,000
synapses for a typical neuron
• Human brain is capable of
processing
10,000,000,000,000,000,000,000,000,000
bits of data per second
• Intelligence has nothing to do with
number of neurons – it has
everything to do with number of
dendrite connections
Random Brain Facts
• World record for time w/o sleep:
• 264 hours (11 days) – Randy Gardner, 1963
• Unconsciousness occurs 8-10 sec after loss of
blood supply to brain
Random Brain Facts
• Changing brain:
• 525 billion neurons in brain at 26 wks
gestation
• 200 billion on day born
• 100 billion today
• Brain is ultimate “use it or lose it”
machine
– “neural sculpting” happens during REM
sleep
• Computer/TV has huge impact on
brain
• Recommend no TV/internet 0-2 yrs
– Sesame Street?
Random Brain Facts
• Humans can process 400-600 words/min
– Talk about 100-125 words/min
• Speaker needs to fill in gaps to avoid boredom, mind
wandering
• Older people take longer to learn, but retain
information as well as younger ppl
• Before age 5, brain is very plastic – can
simultaneously adapt after injury
– After age 5, severe, permanent damage more likely
• Ex – 5 y.o. boy w/ severe seizures had entire left hemisphere
removed – paralyzed on right side, but scored above avg on
intelligence tests, finished college & grad school – today an executive
Random Brain Facts
• Brain disorders cost
Americans more than $600
billion a year
• Alcohol use in teens
devastating to the pre-frontal
cortex
• Mature neuron has
myelin sheath protection,
young adolescent brain
does not
– MN in top 5 for alcohol
consumption
– Also top 5 for FAS cases
In the beginning …



In the early years, the brain nearly
triples in size and weight.
There is a huge buildup of neural
connections.
This is followed by a massive
reorganization at the terrible two’s.
The Neuron
Neuron Migration
Neuronal Cell Migration - “Brain Density"
Newborn
3 Months
Two Years
Rethinking the Brain, Families and Work Institute, Rima Shore, 1997.
Neuron Migration
Neuronal Cell Migration - “Brain Density"
Structure and
Changes in the
Teenage Brain
By adolescence, the
brain has almost
reached its full size, and
conventional wisdom
had it that the
adolescent brain was
fully developed.

The conventional
wisdom was wrong …
as every parent and
teachers of adolescents
had already suspected.
What’s not finished 1 of 3?

The prefrontal lobes – this part of the
brain is still developing during the
teen years, perhaps not finished into
the late twenties.
The prefrontal lobe is responsible
for the following:
Reasoning ability
Goal and priority setting
Ability to make sound judgments
Planning and organization of multiple tasks
Impulse inhibition
Self-control
Emotional control
Determining right from wrong
Determining cause and effect relationships.
And that’s not quite it either … (2
of 3)

Cerebellum isn’t finished either!
• Best known for controlling movement,
but also coordinates cognitive
processes.
• Physical activity influences the
cerebellum, so …
• Sports/physical activities are good
for the brain.
Unfinished business, part 3

The amygdala is
used for instinctive
emotional reactions.
Amygdala
Matures before the frontal
lobe.
 So, adolescents respond with
gut reactions before
reasoned ones.
 This accounts for impulsive
and risky behavior.

Also accounts for …
Courage
Medal of Honor (MOH)
“(they) have courage to the men
around them. And, finally, they
are young men.” Richard
Nixon to the MEDAL OF HONOR
RECIPIENTS 1969
MOH recipients range from 12 to
30
Behavior Effects of the
Amygdala

Erratic Behavior
• Compulsive Behavior
• Pleasure/Thrill Seeking


Alcohol-Drug Abuse
Promiscuity
• Limits


“How much can I do?”
“How much can I get away with?”
You’ll recognize this …

The “Emotional Crisis”
• To us, yet another frivolity
• Very real to them
SOLUTIONS



Keep a level head.
Remain calm.
Sympathize. I say,
“Unfortunate.”
Remain firm – this does not
excuse behavior.