The Brain
AP Psychology Chapter 2
Techniques to Study the Brain
Brain lesions experimentally destroy brain tissue to
study animal behaviors after such destruction
Usually done for scientific and medicinal purposes
Not done on humans – unethical
Techniques to Study the Brain
Naturalistic Observation
Alterations in brain
morthpology are now
being study and
catalogued
EEG
(Electroencephalography)
Electroencephalography
(EEG) is the recording of
electrical activity along the
scalp. EEG measures
voltage fluctuations
resulting from ionic
current flows within the
neurons of the brain.[1]
In clinical contexts,
Techniques to Study the Brain
MRI
Magnetic resonance
imaging
Uses magnetic fields and
radio waves to create
computer generated
images of brain tissue
Techniques to Study the Brain
PET Positron emission
tomography
Visual display of activity
that detects radio active
form of glucose while
brain performs a specific
task
Phineas Gage
Phineas Gage
Phineas Gage is often
referred to as one of the
most famous patients in
neuroscience. He suffered a
traumatic brain injury when
an iron rod was driven
through his entire skull,
destroying much of his
frontal lobe. Gage
miraculously survived the
accident, but was so changed
as a result that many of his
friends described him as an
almost different man
entirely.
Phineas Gage
http://www.youtube.com/watch?v=oPAqTP7058Q
Older Brain Structures
The Brainstemisthe oldest part of the brain, beginning
where the spinal cord swells and enters the skull. It is
responsible for automatic survival functions.
Brain Stem
The Medulla [muh-DUL-uh] is
the base of the brainstem
It controls autonomic functions
and relays nerve signals between
the brain and spinal cord.
respiration
blood pressure
heart rate
reflex arcs
vomiting
Brain Stem
The Medulla [muhDUL-uh] is the base of
the brainstem that
controls heartbeat and
breathing.
Brain Stem
The Thalamus [THALuh-muss]is the brain’s
sensory switchboard,
located on top of the
brainstem. It directs
messages to the sensory
areas in the cortex and
transmits replies to the
cerebellum and
medulla.
Pons
The Pons plays a role in
muscle coordination.
Pons
Reticular Formation
•Reticular Formationisa nerve
network in the brainstem
that plays an important role
in controlling arousal.
• Damage to this causes a
disorder called narcolepsy in
which a person falls asleep
suddenly during the daytime
and cannot resist the sleep.
Cerebellum
The “little brain”
attached to the rear of
the brainstem. It helps
coordinate voluntary
movements and
balance.
The Limbic System
The Limbic Systemisa
doughnut-shaped
system of neural
structures at the border
of the brainstem and
cerebrum, associated
with emotions such as
fear, aggression and
drives for food and sex.
It includes the
hippocampus, amygdala,
and hypothalamus.
The Limbic System

Amygdala [ah-MIG-dah-la]
 two almond-shaped neural clusters that are components
of the limbic system and are linked to emotion (fear
and aggression)
 http://www.youtube.com/watch?v=cu7A8LIzL1o
Hippocampus
Memory – Involved in processing new memories.
Everything you learn filters through hippocampus
first.
Clive Wearing
http://www.youtube.com/watch?v=c62C_yTUyVg
 Hypothalamus

neural structure / below (hypo) the
thalamus; Basic Drives:
hunger
 thirst
 body temperature
 Sex drive (libido)





helps govern the endocrine system
via the pituitary gland
is linked to emotion
Sometimes referred to as the
pleasure center
Two Parts to Hypothalamus
Ventromedial – “Vomit” Tells you
when to stop eating
Lateral – “ Lets Eat” Tells you
when you are hungry
Reward Center
Sanjiv Talwar, SUNY Downstate
Rats cross an electrified
grid for self-stimulation
when electrodes are
placed in the reward
(hypothalamus) center
(top picture). When the
limbic system is
manipulated, a rat will
navigate fields or climb
up a tree (bottom
picture).
Hemispheres of the Brain
Left:
Language and logic
Right:
Spatial, creative
Why do most strokes affect the right
side of the body?
Most strokes occur in the left hemisphere
Cerebral Features:
• Gyri – Elevated ridges “winding” around the brain.
• Sulci – Small grooves dividing the gyri
– Central Sulcus – Divides the Frontal Lobe from the Parietal
Lobe
• Fissures – Deep grooves, generally dividing large
regions/lobes of the brain
– Longitudinal Fissure – Divides the two Cerebral Hemispheres
– Transverse Fissure – Separates the Cerebrum from the
Cerebellum
– Sylvian/Lateral Fissure – Divides the Temporal Lobe from the
Frontal and Parietal Lobes
Gyri (ridge)
Sulci
(groove)
Fissure
(deep groove)
http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif
Cerebral Cortex - The outermost layer of gray
matter making up the superficial aspect of the
cerebrum.
Cerebral Cortex
Cerebral
Cortex
http://www.bioon.com/book/biology/whole/image/1/1-6.tif.jpg
The Cerebral Cortex
(Thin layer of densely packed neurons: .0039-inch)
 Cerebral Cortex
 intricate fabric of interconnected neural cells that
covers the cerebral hemispheres (20 billion nerve
cells!)
 body’s ultimate control and information processing
center
 The larger the cortex, more adaptability, capacity for
learning
 Wrinkles = fissures (3 sq ft w/o them!)
 *Perceiving, thinking, speaking*
 Glial Cells
 cells in the nervous system that support, nourish,
and protect neurons
 Aka neuron nannies or glue cells
The Cerebral Cortex
Lobes of the Brain (4)
Frontal
Parietal
Occipital
Temporal
http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
* Note: Occasionally, the Insula is considered the fifth lobe. It is located deep
to the Temporal Lobe.
Lobes of the Brain - Frontal
The Frontal Lobe of the brain is located deep to the
Frontal Bone of the skull.
• It plays an integral role in the following functions/actions:
- Memory Formation
- Emotions
- Decision Making/Reasoning
- Personality
(Investigation:
Gage)
InvestigationPhineas
(Phineas
Gage)
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-
Lobes of the Brain - Parietal Lobe
The Parietal Lobe of the brain is located deep to the
Parietal Bone of the skull.
• It plays a major role in the following functions/actions:
- Senses and integrates sensation(s)
- Spatial awareness and perception
(Proprioception - Awareness of
body/ body parts in space and
in relation to each other)
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Lobes of the Brain – Occipital Lobe
The Occipital Lobe of the
Brain is located deep to the
Occipital Bone of the Skull.
Its primary function is the
processing, integration,
interpretation, etc. of VISION and
visual stimuli.
•
Modified from: http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg
Lobes of the Brain – Temporal Lobe
The Temporal Lobes are located on the sides of the
brain, deep to the Temporal Bones of the skull.
They play an integral role
in the following functions:
•
- Hearing
- Organization/Comprehension of
language
- Information Retrieval
(Memory and Memory Formation)
Modified from: http://www.bioon.com/book/biology/whole/image/1/18.tif.jpg

The
Cerebral
Cortex
Motor Cortex

at the rear of the frontal lobes / controls voluntary movements

What parts of body occupy most cortical space?

Fingers and mouth (require most precise control)

Cerebral
Cortex
Sensory Cortex


at the front of the parietal lobes / registers and
processes body sensations
The more sensitive the body region, the more area
occupied in the sensory cortex
The Cerebral Cortex
* Note: Homunculus literally means “little person,” and may refer to one whose body shape is
governed by the cortical area devoted to that body region.
Q: What do you notice about the proportions depicted in the
aforementioned homunculus?
A: They are not depicted in the same scale representative of the human body.
Q: What is meant by depicting these body parts in
such outrageous proportions?
A: These outrageous proportions depict the cortical area devoted to each
structure.
- Ex: Your hands require many intricate movements and sensations to function
properly. This requires a great deal of cortical surface area to control these
detailed actions. Your back is quite the opposite, requiring limited cortical area to
carry out its actions and functions, or detect sensation.
Back-Hom.
The Cerebral Cortex

Functional MRI scan
shows the visual cortex
activated as the subject
looks at faces
Visual and Auditory Cortex
Association Areas

More intelligent animals have increased “uncommitted” or association areas of the cortex

Association areas = 75% of cortex

Interprets, integrates and acts on info processed by sensory areas

Associates sensory input with stored memories (complex mystery)
Language and the Brain

Broca’s Area
 Location: lower left frontal lobe
 Major Function
 directs muscle movements making speech
 Speech Production
 Involved in the analyzing the grammatical structures of
sentences

Composition
 Contains the motor neurons involved in the control of
speech
Broca’s Aphasia
Aphasia refers to the speech impairment caused by brain
damage
Patients know what they want to say but have a hard time
getting it out.
Spoken sentences lack prepositions and conjunctions
They are typically able to comprehend words and produce
sentences however they must be simple grammatical
sentences.
Reading and writing are not as affected however, it can be in
some cases
http://www.youtube.com/watch?v=f2IiMEbMnPM
Wernickes Area
Locations
Left temporal lobe
Major Function
Involved in the interpretation of speech
Known as the language comprehension
center
Vital for locating appropriate words from
memory to express meaning
Wernickes Aphacia
Trouble with speech comprehension
Can’t produce meaningful sentences. Can string
together words but what they say is nonsensical
Leave out key words and substitute random or invented
words
Talk excessively
http://www.youtube.com/watch?v=dKTdMV6cOZw
Specialization and
Integration
Specialization and
Integration
 Brain activity when hearing, seeing, and speaking words
Brain Reorganization
 Plasticity
 brain’s capacity to modify itself
 brain reorganizes / compensates after
damage, injury
 children have the most plasticity
 Example: blind and braille- one finger
used: sense of touch invades visual cortex
 http://www.youtube.com/watch?v=2MKN
sI5CWoU
Review Question
1.
When stroking the face of someone who’s hand
has been amputated, why did the subject feel the
sensation not only on his face, but also on his
amputated (“phantom”) fingers?
Answer: Hand area of the sensory cortex is no longer
used, thus fibers from other sensory areas invade
the space. (Note that the hand area is between
the face and arm regions of the sensory cortex.)
In other words…. Plasticity!
Plasticity
Our Divided Brain
Severed Corpus Callosum
http://www.youtube.com/watch?v=lfGwsAdS9Dc
Our Divided Brain
Corpus callosum
 Corpus
Callosum

large band of neural
fibers: 200,000,000!

connects the two
brain hemispheres

carries messages
between the
hemispheres (billion
pieces of info /
second!)
Our Divided Brain

The information
highway from the eye
to the brain
Split Brain

Isolate the 2 hemispheres by
cutting the connecting fibers
between them (corpus
callosum)

To remedy uncontrollable
epileptic seizures
 Testing the “split brain”
proves specific functions
of each hemisphere
The Split Brain Experiment
Dr. Gazzaniga- 1967
Stare at the Dot…..
he.art
1. Which word would the split-brain patient
verbalize seeing? Why?
2. Which word, when asked to point with
his left hand, would he report seeing?
Why?
Split Brain
Explain the following…
The Split brain
1. If this visual was shown to
the right hemisphere of a
split brain patient, how
might the patient identify
the object?
The Split Brain
Interesting facts about the split brain:

Subjects can simultaneously draw different figures with the left
and right hand.

When the 2 hemispheres are at odds, the left will rationalize
reactions it doesn’t understand.

The hemispheres are an “odd couple”, each with “a mind of its
own.”
The Split Brain
Which hemisphere is more active with…
Simple requests
Right brain
Perceiving objects
Right brain
Decision making (deliberative)
Left brain
Quick intuitive responses
Right brain
Recognizing faces
Right brain
Perceiving , expressing emotion
Right brain
Hemispheric Differences in the Intact Brain
Hemispheric specialization = lateralization
Blood flow, glucose, brain waves detected between hemispheres for
perceptual tasks and speaking, calculating tasks (EEG, PET, FMRI)
Sedative to artery to specific hemisphere: alters specific functions of
the body
If left hemisphere is sedated, what functions would be lost?
Language, right side of body limp
If sedative to right hemisphere?
Difficulty identifying themselves in altered photo, left side limp
Questions to consider….
1. If a word is flashed to your right hemisphere
(through your left visual field), why does it take
you slightly longer to state what you see than it
would if flashed to your left hemisphere?
Process time through the corpus callosum
2.
Which hemisphere would a deaf person use for
sign language?
right (visual / spatial) or left (language)?
•
Left: to the brain, language is language
Handedness
What percentage of humans are right handed?
90%
What ultimately makes you right or left handed?
Genetics? Pre-natal? Social-Cultural?
What expressions can you think of that discriminate
against “lefties?”
Right on / right hand man / righteous / right mind -- out
in left field / left-handed compliment
Lefties tend to be…..
Musicians
Mathematicians
Professional baseball / cricket players
Architects
artists
Disappearing Southpaws

The percentage of left-handers decreases sharply in samples of
older people (adapted from Coren, 1993).
Percentage of 14%
left-handedness
12
The percentage of
lefties sharply
declines with age
10
8
6
4
2
0
10
20
30
40
50
Age in years
60
70
80
90
Brain Structures and their
Functions
Neuroscience, Genetics and Behavior
True or False?
“Basic biological processes underlie all human
behavior.”
Various branches of psychology rest on this
foundation.
Biological Psychology
(or Psychobiology)
The most significant transformation in modern
psychology
AKA Biopsychologists, behavioral neuroscientists,
behavior geneticists, physiological psychologists,
neuropsychologists…
An intro to neuroscience…
Explain the following…
1.
“Modern psychology views each individual as a
biopsychosocial system.”
2.
“Everything psychological is simultaneously
biological.”
3.
“The mind is what the brain does..”
4.
“A brain simple enough to be understood is too
simple to produce a mind able to understand it.”
Introducing the neuron…

Simple definition:


a nerve cell
The incredible neuron….


basic unit of information processing and the building block of
the brain. (and nervous system)
Working together with other neurons and cells throughout the
body, it allows us to think, feel, move and breathe.
A vastly complex system…
Facts about neurons:

100 billion neurons in the human brain and CNS!
(and 400 trillion synapses!)

A grain of sand-size part of the human brain holds
100,000 neurons!
Neural Structure
 Dendrite (receives impulse)
 Branching extensions of a neuron / receive messages /
conduct impulses toward the cell body
 Axon (transmits impulse)
 extension of a neuron, ending in branching terminal fibers,
through which messages are sent to other neurons or to
muscles or glands
Remember: “Axons speak, dendrites listen…”
 Myelin Sheath(speeds impulse)
 a layer of fatty cells segmentally encasing the fibers of many
neurons
 Speeds transmission of neutral impulses
Neural Structure
So what happens when the myelin sheath begins to
wear out?
Alzheimer's (impedes transmissions affecting thought
process)
Multiple sclerosis: interferes with muscle control (as
message to muscles is impeded..)
Neural Structure
Neural Communication
“an electrochemical process…”
“Neural communication is a conversation between cells
that generates our thoughts, actions, moods and
memory.”
Neural Communication

Action Potential



a neural impulse; a brief electrical charge that travels down an
axon
Stimulated when neuron receives signals from sense receptors
stimulated by heat, pressure or light
generated by the movement of positively charged atoms in and
out of
channels in the axon’s membrane
Neural Communication
“What one neuron tells another neuron is simply how much it is
excited.”

Each neuron has a threshold…

the level of stimulation required to
trigger an action potential (or neural impulse)
Threshold is determined by excitatory (accelerator) and
inhibitory (brakes) triggers that determine the action potential
(neural impulse)
Neural Communication…
Neurons generate electricity from chemical events (like
batteries)
The chemistry to electricity process involves the
exchange of ions
Ions: electrically charged atoms
Ions…
Resting Potential
Fluid inside a resting axon has negatively charged atoms
Fluid outside the axon membrane has positively charge
atoms
Natural state of inside / outside ions = resting potential
Axon’s surface is selectively permeable (it decides
what it allows in..)
Reaching a Neuron’s
Threshold…
When the neuron fires…
Axon opens gates (selectively permeable) and +charged sodium ions
flood the membrane
+sodium ions cause depolarization
Depolarization causes reaction as axons pass the impulse down the
chain (like dominoes)
Opens and closes 100-1000 times /second!
Reaching a Neuron’s
Threshold…
Refractory Period
Once impulse has been passed, the axon pumps +ions
back out of membrane, and thus recharges
All or none response
Increased stimulus does not increase the action
potential’s intensity (a gun either fires or doesn’t)
Neural Communication
Cell body end
of axon
Direction of neural impulse: toward axon terminals
Neural Communication
 Synapse (Where the action is…)
 gap between the axon tip of the sending neuron and the
dendrite or cell body of the receiving neuron
 tiny gap at this junction is called the synaptic gap or cleft
(less than a millionth of an inch!)
 Neurotransmitters
 chemical messengers that cross the synaptic gaps between
neurons
 neurotransmitters bind to receptor sites(“lock and key”) on
the receiving neuron, thereby influencing whether it will
generate a neural impulse

Thus ions passed on to new neuron: exciting or inhibiting its
readiness to fire..
Neural Communication
Reuptake
Excess neurotransmitters are reabsorbed by the sending
neuron
Neural Communication
Neurotransmitters
About 75 have been discovered
We will study 7-8
Neurotransmitters
(Take notes on last 2 listed)
Neurotransmitters
GABA
Glutamate
Inhibitory neurotransmitter
Excitatoryneurotrasmitter
Undersupply = seizures,
tremors, insomnia
Invovled in memory
Too much = migraines,
seizures
Excitotoxicity: “excite a
neuron to death” (glial cells
help prevent…)
Chinese food- MSG
(glutamate) = headaches
Neurotransmitters
 Acetylcholine [ah-seat-el-KO-leen]
 ACh
 triggers muscle contraction (movement,
learning, memory)
 Undersupply = Alzheirmer’s
Neurotransmitters
 Endorphins [en-DOR-fins]
 “morphine within”
 natural, opiate-like neurotransmitters
 linked to pain control and to pleasure
 “Runners high”
 Opium, heroine addicts: brain stops
producing natural opiates, thus
“withdraws”
Neurotransmitters…
Norepinephrine
Mood
Too much = mania / too little = depression
Imbalance = bipolar disorder
Neurotransmitters
Serotonin
Sleep, eating, mood
Related to depression
Prozac (anti-depressant drug) raises serotonin levels
Neurotransmitters
Dopamine
Perceptual awareness, muscle control
Too much = Schizophrania (up to 6x more dopemine)
A Beautiful Mind / The Soloist
Too little = Parkinson’s Disease (tremors: Muhammad Ali)
Drugs Affect
Neurotransmission
Drugs can be used to affect communication at the
synapse
Agonists excite, or mimic the neurotransmittors / or
block reuptake (drug addicts and withdraw)
Antagonists block, or inhibit neurotransmitters signal
(examples=Botox/ botulism blocks Ach)
A complicated process: Brain has blood-brainbarrier that
blocks out unwanted chemicals
Neural Communication
Serotonin Pathways
Dopamine Pathways
Remember…
Communication within the neuron is…….
Electrical
Communication between neurons is….
chemical
Glial cells (Glia)
Make up 90% of brain’s
cells
Protect, nourish neurons
Current research suggests
possible action potentials,
debate as to role…
See p. 45: Alchemy of Mind
An Alchemy of Mind
Explain fully each of the following quotes from your reading.
 “Neurons speak an elite pidgin neither chemical nor
electrical but a lively buzz that joins the two, an
electrochemical lingo all their own.”
 “It is important to realize that what one neuron tells another
neuron is simply how much it is excited.”
 It is a small liquid space, as is the air between two
whispering lovers, yet so much life happens there. Each
junction is a bazaar full of commerce, intrigue and
possibility. In the brain, everything depends on almost
nothing, a lively space….”
 “Coexisting as they must, both neurons and glia are
dependable, dependent… central to the brain’s social fabric
and perpetual hum.”
The Nervous System

Nervous System



Central Nervous System (CNS)


the body’s speedy, electrochemical communication system
consists of all the nerve cells of the PNS and CNS
the brain and spinal cord (encased in bone)
Peripheral Nervous System (PNS)

connect the central CNS to the rest of the body’s sense receptors
The Nervous System
Nervous
system
Central
(brain and
spinal cord)
Peripheral
Autonomic (controls
automatic action of
internal organs and glands)
Somatic (Skeletal) (controls
voluntary movements of
skeletal muscles)
Sympathetic
(arousing: flight or fight)
Parasympathetic
(calming)
The Autonomic Nervous System

Autonomic Nervous System


part of the PNS: controls the glands and the muscles of the
internal organs (involuntary)
A Dual System

Sympathetic Nervous System


arouses the body, mobilizing its energy in stressful situations (“Fight
or flight”, or “sympathy in crisis”)
Parasympathetic Nervous System
calms the body, conserving its energy
 “paramedics to calm down”- lowers heartbeat etc.

The Nervous System
The Nervous System
The Peripheral Nervous System
Links CNS to body’s sense receptors
For each of the following, identify it as a function of the Somatic
or Autonomic Nervous System.
Sneezing
Turning the page
Scratching your head
Breathing
Kissing your date
Digesting your food
Communication in the Nervous System

Nerves




neural “cables” containing millions of axons
part of the PNS (carry PNS info)
connect the CNS with muscles, glands, and sense organs
Extend through the body
Communication in the Nervous System
 3 neurons that carry info in the nervous
system

Sensory Neurons (afferent: millions!)


Motor Neurons (efferent: millions)


neurons that carry incoming information from the sense receptors
to the central nervous system
carry outgoing information from the CNS to muscles and glands
Interneurons (billions!)

CNS neurons that internally communicate / process sensory and
motor neurons (most complex)
The Central Nervous System
“The motherboard of our humanity…”
10’s of billions of neurons
Brain and spinal cord
Spinal cord: Information highway connecting PNS to
the brain
Reflexes
Spinal Reflex: Autonomic response to stimuli (Single
sensory neuron, single motor neuron,
interneuron:…..Brain’s not involved!)
Pain Reflex

Sensory neuron, interneuron, motor neuron

a simple, automatic, inborn response to a sensory stimulus
The Brain
Center for all sensory information and voluntary
movement (receives, interprets, decides…)
Without the brain…no pain or pleasure, no voluntary
movement
Neural Networks
A Complex Mystery…
Neurons in the brain
connect with one
another to form networks
Inputs
The brain learns by modifying
certain connections in
response to feedback
 Neural Networks
 interconnected neural
cells
 with experience,
networks can learn, as
feedback strengthens or
inhibits connections
Outputs
that produce certain
results
 computer simulations of
neural networks show
analogous learning
In other words…
“Neurons that fire together... wire together.”
The Endocrine System
The body’s 2nd communication system
Interconnected with nervous system
Endocrine System
ES glands produce hormones
Hormones travel through bloodstream to affect body
Influences growth, mood, metabolism, reproduction
etc.
Thus ES works to keep body in balance in response to
stress, exertion, thoughts etc.
“Snail mail”- Much slower to process, several seconds,
but lasts longer…
Important Glands…
Pituitary Gland (the master gland..)
Pea sized, in middle of brain
Influences growth
Influences other Endocrine glands’ release of hormones
Controlled by hypothalamus (brain)
Brain – pituitary – other glands – hormones – brain
(complex system: blend of Endocrine system and
nervous systems)
Pituitary Gland
Adrenal Glands
Located on top of kidneys
Release epinephrine and norepinephrine (adrenaline
and noradrenaline)
Heart rate, blood sugar, blood pressure etc.
Adrenal Glands
What do you know about the human
brain?
Answer the following as true or false.
1.
The larger the brain, the smarter the animal.
2.
The brain’s structure is a better indicator of
intelligence than it’s size.
3.
The right side of the brain controls the right side of
the body, and so on with the left.
4.
You fall in love with your heart, not your brain.
5.
Your brain uses 20% of your body’s energy, but makes
up only 2% of your body’s weight.
What do you know about the human
brain?
True-False continued…
6.
Your brain is about the size of a cantaloupe and is
wrinkled like a walnut.
7.
Your brain feels like a ripe avocado and looks pink because
of the blood running through it.
8.
The baby’s brain grows 3x in size during its first year.
9.
At birth, the human brain weighs 4/5 of a pound, while
an adult’s weighs about 3 pounds.
10.
Your brain generates about 25 watts of power while awakeor enough to illuminate a light bulb.
The typical human brain…
o
contains about 100
billion neurons
o
consumes about ¼ of
the body’s oxygen
o
spends most of the
bodies calories
o
Is 70% water!!!
o
weighs about 3 pounds