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The Brain
Unit 3 B
The Brain
Phineas Gage Video
• http://www.youtube.com/watch?v=oPAqTP
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Ways we Study the Brain
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Accidents
Lesions
EEG
CAT Scan
PET Scan
MRI
Functional MRI
Accidents
Phineas Gage Story
• Personality changed
after the accident.
What does this tell us?
• That different part
of the brain control
different aspects of
who we are.
Lesions
• Purposeful
removal or
destruction of
some part of the
brain.
• Frontal
Lobotomy
Electroencephalogram
• EEG
• Detects brain
waves through
their electrical
output.
• Used mainly in
sleep research.
Computerized Axial Tomography
• CAT Scan
• 3D X-Ray of
the brain.
• Good for
tumor locating,
but tells us
nothing about
function.
CT example
Magnetic Resonance Imaging
• MRI
• More detailed picture
of brain using
magnetic field to
knock electrons off
axis. Shows the
structure of the brain
• Takes many still
pictures and turns
images into a movie
like production.
• Does not study
function!
MRI example
• Notice the tumor…
Positron Emission Tomography
• PET Scan: depicts brain activity by showing each brain
areas’ use of its chemical fuel
• Measures how much of a chemical the brain is using (usually
glucose consumption). Also shows activity of the brain
• Good for studying function.
PET scan
• Depression
Functional MRI
• Combination of PET and MRI: shows
functioning and activity
• fMRI is good for function, hence the f.
f MRI example
• Amygdala activation
• Primary Visual
Cortex activation
• Dr. Jones, a brain researcher, is investigating the
connection between certain environmental
stimuli and brain processes. Which types of
brain scans is she most likely to use?
• A. MRI and CAT
• B. CAT and EKG
• C. PET and fMRI
• D. EKG and CAT
• E. lesioning and MRI
• The answer was C. The CAT and the MRI
give insight into brain structure, not
function.
Brain Structures
1. Hindbrain/brain
stem
2. Midbrain/limbic
system
3. Forebrain/cerebr
al cortex
Cerebral cortex is
part of forebrain
The brain was built
like a house, bottom
to top.
The hindbrain controls
basic functions like
breathing. Shared with
animals
The forebrain is the
most complex
Hindbrain
• Structures on top of our spinal cord.
• Controls basic biological structures.
• All animals have hindbrains!
The brain in
purple makes up
the hindbrain.
Medulla Oblongata
• Located just
above the spinal
cord.
Involved in control
of
• blood pressure
• heart rate
• breathing. (basic
stuff!)
Pons
• Located just above
the medulla.
• Connects hindbrain
with midbrain and
forebrain. Helps
coordinate movements
• Involved in facial
expressions.
• Bladder control, eye
movement, posture,
hearing and more
Cerebellum
• Bottom rear of the
brain.
• Means “little brain”
• Coordinates fine
muscle movements
and balance.
Kicking a goal
in soccer
What is reticular formation?
• Part of brain – affects consciousness. Sleep
meds affect this part of the brain. Damage
leads to a coma. Controls arousal and ability
to focus attention
Midbrain
• Consists of the
thalamus
• Cerebellum and
the Limbic system
Cerebellum
The Limbic System deals
with memory and emotions
Thalamus
• Switchboard “relay
station” of the brain.
• Receives sensory
signals from the
spinal cord and
sends them to other
parts of the
forebrain.
• Every sense except
smell.
Hypothalamus
• Maybe most
important structure
in the brain.
Controls and regulates
the temperature,
hunger, thirst
Controls the endocrine
system. All the
The most powerful
glands
structure in the brain.
Rat with an Implanted
Electrode in pleasure center
of Hypothalamus
Hypothalamus
Lateral Hypothalamus
• When stimulated it makes
you hungry.
• When lesioned (destroyed)
you will never be hungry
again.
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Larger Hunger
Ventromedial Hypothalamus
• When stimulated you feel
fufull.
• When lesioned you will never
feel fullulagain.
• Very Minute Hunger
Hippocampus
• Involved in the
processing and
storage of
memories.
• Its proximity to
your emotional
centers explains
why memories
and emotions are
so linked!
http://www.youtube.com/watch?
v=WmzU47i2xgw&list=PL2920
A92123EAF834&index=76
Amygdala
• Brain part
involved in
telling your
body to
produce
norepinephrin
e (adrenaline)
• More involved
in volatile
emotions like
anger.
The emotion of anger has
not changed much
throughout evolution.
What is the cerebral cortex?
The Cerebral Cortex
• Made up of densely
packed neurons we call
“gray matter”
• Wrinkles are called
fissures.
• If you lay brain out it
would be as big as a large
pizza.
• It’s divided into 2
hemispheres and 4 lobes!
• Left and right
hemispheres
Cerebral Cortex
• What makes us
human, animals
without a large
cortex act on
instinct
• Cc contains 20-23
billion nerve cells
• 300 trillion
synaptic
connections
• Glial cells support
these nerve cells.
Neurons are like
queen bees they
cannot feed or protect
themselves glial cells
worker bees they
provide nutrients, and
insulating myelin,
mop up
neurotransmitters ,
chat with neurons
The Cerebral Cortex is made up
of four Lobes. Label your brain
outline!
What are Frontal Lobes?
• Abstract thought and
emotional control and
planning.
• Contains Motor Cortex,
Broca’s area.
• Lobotomies damage
this.
• Suppresses the
Amygdala.
What is the motor cortex?
• Part of the brain in the frontal lobe that tells
my body how to move (like typing this).
What is the sensory cortex?
It’s the part that deals with touch sensations. It’s
In the parietal lobe.
What are Motor and
Sensory Cortexes?
The wires are switched! Right controls left!
The motor cortex is in which lobe?
Sensory homunculus
A visual representation of how much space
your brain needs to operate parts of your body.
how big the face and hands are. How small everything else is!
Notice
Motor strip and
homunculus
Motor strip
Parietal Lobes
Where would this
girl feel the most
pain from her
sunburn?
• Contain Sensory
Cortex: receives
incoming touch
sensations from
rest of the body.
• Most of the
Parietal Lobes are
made up of
Association Areas.
Occipital Lobes
• Think “optical”.
• Contains Visual
Cortex: interprets
messages from our
eyes into images we
can understand.
Notice how close the auditory cortex is to the ears.
Association areas
• About ¾ of the brain which is not involved in the
sensory or motor activity
• Association areas integrate information
• These areas link sensory inputs with stored
memories –Very important
• Found in all 4 lobes
• In frontal lob association areas allow us to learn,
judge and process new memories but damage
would not allow you to plan ahead
Association Areas continued
• In parietal lobes assoc. areas allow us to use
math and spatial reasoning, recognize faces
Figure 3B.16 Areas of the cortex in four mammals More intelligent animals have increased
“uncommitted” or association areas of the cortex. These vast areas of the brain are responsible for
integrating and acting on information received and processed by sensory areas.
© 2011 by Worth Publishers
Temporal Lobes
• Process sound sensed
by our ears.
• Interpreted in
Auditory Cortex.
• NOT LATERALIZED.
• Sound goes to both
temporal lobes
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Aphasia- impaired use of
language
Broca’s area – production of
speech think (boca) (left side
of the frontal lobe).Struggle to
speak but can sing and
comprehend
• Angular gyrus- speak and
understand cannot read aloud
• Wernicke’s area deals with
comprehension of language.
Speak meaningless words also
disrupts comprehension
Which side of brain are we seeing?
Aphasia Videos
• http://www.youtube.com/watch?v=1aplTvE
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• http://www.youtube.com/watch?v=aVhYN7
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Figure 3B.18 A simplified model of brain areas involved in language processing
© 2011 by Worth Publishers
Figure 3B.19 Brain activity when hearing, seeing, and speaking words PET scans such as these
detect the activity of different areas of the brain.
© 2011 by Worth Publishers
Specialization and Integration in Language
Brain Activity when Hearing, Seeing,
and Speaking Words
Which side of the brain are we seeing?
Brain Plasticity
• The idea that the
brain, when damaged,
will attempt to find
news ways to reroute
messages.
• Children’s brains are
more plastic than
adults.
• Neurogenesis- the
ability of the brain to
make new neurons
Video Brain Plasticity
• http://www.youtube.com/watch?v=rDTiZpP
yqRk
• http://www.youtube.com/watch?v=D0njlDS
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Brain plasticity
Neurons’ ability to re-route
their messaging in case of
injury.
• When brain researchers refer to brain plasticity,
they are talking about
• A. the brain’s ability to quickly regrow damaged
neurons
• B. the surface texture and appearance caused by the
layer known as the cerebral cortex
• C. the brain’s versatility caused by the millions of
neural connections
• D. our adaptability to different problems ranging
from survival needs to abstract reasoning
• E. new connections forming in the brain to take
over for damaged sections
What is Split Brain?
Demonstration: Any volunteers?
The Corpus Callosum
The corpus callosum
is cut to prevent seizures
from spreading to the other
side of the brain.
Divides the 2
hemispheres.
Divides the
left from
right sides.
A Tour Through The Brain:
Lateralization
• The left and right
hemispheres of the
brain each specialize
in particular operations.
Figure 3B.22 The information highway from eye to brain
Information from the left half of your field of vision goes to your right hemisphere, and information
from the right half of your visual field goes to your left hemisphere, which usually controls speech.
(Note, however, that each eye receives sensory information from both the right and left visual fields.)
Data received by either hemisphere are quickly transmitted to the other across the corpus callosum. In
a person with a severed corpus callosum, this information sharing does not take place.
© 2011 by Worth Publishers
Split Brain Patients
Those who, due to
epilepsy, have
their corpus
callosum cut or
removed.
Visual Information
• Visual information directed to each side of
the brain comes from visual fields not from
the eyes. The left eye does not send
information to the right hemisphere and
vice versa. The RIGHT HALVES of each
eye send information to the right
hemisphere and vice versa
Figure 3B.23 Testing the divided brain When an experimenter flashes the word HEART across
the visual field, a woman with a split brain reports seeing the portion of the word transmitted to her
left hemisphere. However, if asked to indicate with her left hand what she saw, she points to the
portion of the word transmitted to her right hemisphere.
From Gazzaniga, 1983
© 2011 by Worth Publishers
A Tour Through The Brain:
Split-Brain Research
(Continued)
Split Brain Video
• http://www.youtube.com/watch?v=aCv4K5
aStdU
• http://www.youtube.com/watch?v=8C8qu8
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Experiment #1 Split-brain
patients
• Experimenter shows fork to left hemisphere
(presents to the right side)
• Participant is asked what he saw…
• He states “fork”
• Experimenter shows spoon to right hemisphere
• Participant is asked what he saw
• Response: “I don’t know”
• Participant is asked to reach in a bag with left
hand (right hemisphere) to retrieve what he saw
• He pulls out a spoon…explain?
Other weird issues with splitbrain
• A split-brain patient was asked what he wanted to
do with his life…
– Left hemisphere wrote: architect
– Right hemisphere wrote: race car driver
• Suicide case study
– Left hand (right hemisphere) kept trying to strangle
herself
– Left hemisphere was unaware of why this was
happening and had to defend herself
– Tumor was discovered on her corpus collosum
On the next slide, say the COLOR of
the word without reading the word.
Right-Left Brain Differences for
the rest of us with intact brains
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Right Brain:
Perceptual tasks
Making inferences
Sense of self
Problem seeing other people in
relation to themselves
Cannot recognize themselves in a
mirror
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Left Brain
Speaks
Calculates
Literal interpretation in language
Sign language included
Brain and Consciousness
• What is consciousness? Evolutionary
psychologist believe it must be involved
with reproduction or survival
• But how do brain cells talk to one another?
• No clue how the brain creates
consciousness
• Cognitive neuroscience- science of brain
activities connected to mental processes
• Studies show if you imagine doing
something an fMRI of your brain indicates
activity
• We have dual processing- 2 minds operate
at the same time conscious mind (explicit)
mind and your unconscious mind (implicit)
• Much of our thinking operate outside of
our awareness