Transcript The Organization of the nervous System

How is the
Nervous System
Organized?
Chapter 3
Neuroscience
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Module Objectives
What is the Nervous System?
What are the 3 divisions of the brain?
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Hind-brain
Mid-brain
Forebrain
Discuss how these structures influence
behavior
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Have you heard the expression
“Information is power?” Nowhere
is this truer than in the human
body. Without information, we
could not survive.
Neurons within our nervous system must
take in sensory information from the outside
world and then decide what to do with the
information.
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What is the Nervous System?
The Nervous System is the body’s main
processing system for information.
This consists of structures and organs
that facilitate electrical and chemical
communication in the body.
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The Nervous System
Central Nervous System (CNS)
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The brain
The spinal cord
Peripheral Nervous System
(PNS)
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The main function of the PNS is
to connect the CNS to the limbs
and organs
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CNS-Spinal Cord
The spinal cord transmits signals from
the sensory organs, muscles and glands
to the brain.
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Controls reflexive responses
Conveys signals from the rest of the body
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The spinal cord is like a
communication
superhighway between
the brain and the rest of
the body.
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Spinal cord communication
Communicates with the body below the head
through sensory and motor neurons
Sensory neurons (afferent neurons)
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Carry information about touch, pain, and other
senses from the periphery of the body to the spinal
cord
Motor neurons (efferent neurons)
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Transmit impulses from the central nervous system
to the muscles and glands
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Did you know…?
There are about 3 million miles of axons in
the human brain
Information travels in the nerves at speeds
up to 268 miles per hour!
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How much do you know about
YOUR brain??
Structures of the brain
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What observations can you make
about the brain?
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Looking at the Brain
The exterior covering (cortex) of the
brain is wrinkled which increases the
surface area of the brain
The brain is divided into 2 hemispheres
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Right and left hemispheres
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The hemispheres of the brain are
connected
The Corpus Callosum connects these
hemispheres and allows communication
from one side of the brain to the other.
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Corpus Callosum
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Damage to the Corpus Callosum results
in two independent brains in one skull
Split brain patients allowed researchers to
discover “hemispheric specialization”
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What does a spilt-brain patient
look like?
Review the following video and make some
observations
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Split Brain Research
This research showed that each
hemisphere of the brain is specialized
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The right brain is associated with musical
ability, spatial and drawing tasks
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The left brain is associated with speech and
language.
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Hemispheric Specialization
Left Brain
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Controls Right Side of
Body
Right Side Visual Field
Speaking
Reading
Logical Thinking
Analytical Skills
Sequential Processing
Right Brain
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Controls Left Side of
Body
Left Side Visual Field
Spatial Processing
Facial Recognition
Music
Emotional Expression
Holistic Thinking
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Want to play the Split Brain game?
http://nobelprize.org/educational_games/medicine/splitbrain/about.html
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Take the Wagner Preference
Inventory now!
This quiz will help determine which side
of your brain is most dominant. It can be
found in the Module 2 notes folder.
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How are these brains different?
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Why are they different?
More recently evolved animals have a larger
proportion of the brain taken up by the cerebral
cortex.
The cerebral cortex, made up of four lobes, is involved
in many complex brain functions including:
‐memory
‐perceptual awareness
‐"thinking”
‐language and consciousness
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Does bigger mean smarter?
NO…
larger brains have
nothing to do with
intelligence.
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Did you know…
The brain of Albert Einstein weighed 1,230 grams.
This is far below the average brain weight of 1,400
grams
The brain of an elephant weighs about 4.78 kg
(10.5 lb). An adult human brain weighs about 1.4
kg (3 lb)
The heaviest human brain ever recorded weighed 5
lbs., 1.1 oz (The Guinness Book of World Records, 1997).
The total surface area of the cerebral cortex is
about 2500 sq. cm (~2.5 sq. ft).
It is estimated that there are 60 trillion synapses in
the cerebral cortex.
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Three Divisions of the Brain
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Hindbrain
Midbrain
Forebrain
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The Hindbrain
This is the most primitive division of
the brain.
The structures in the lower brain
tend to be responsible for basic,
reflexive functions.
Includes the cerebellum, Pons, and
medulla
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The Hindbrain
The Medulla is the most primitive and
lowest portion of the hindbrain (Part of
the brain stem).
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It controls basic body functions- heart
beat, digestion and breathing.
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[sensation]
[sleep/wake]
[ “life support” ]
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Pons- provides link (“bridge”)between
the medulla and the cerebellum and rest
of brain
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is involved in respiration, movement,
sleeping, waking, and dreaming.
Cerebellum- “Little brain” – attached to
back surface of brain stem.
Influences balance, coordination and
movement
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Allows you to walk a straight line
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[coordination
and balance]
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Where do complex thought and
behavior come from?
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True or False?
We Only Use 10% of Our
Brain
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True or False?
We Only Use 10% of Our Brain
False!
This is a Psychology Myth…we use all of
brain most of the time.
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Have you ever seen a Kung-Fu
movie?
What is most obvious about a
movie that has been dubbed into
English?
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The language doesn’t match, right?
Imagine if you had to go through
life inside a Kung-fu movie? If your
midbrain was damaged it would
effect your ability to process
auditory information.
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The Midbrain
The midbrain helps us orient our eye and body
movements to visual and auditory stimuli
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Coordination of visual and auditory reflexes
The reticular formation (RF) runs through the
hindbrain and midbrain.
This finger-shaped structure filters incoming sensory
information and alerts the higher brain centers to
important events.
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The Forebrain
This the largest, most complicated and
most advanced brain division.
This area of the brain is associated with
complex thought and behaviors:
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The ability to concentrate, elaboration of
thought, judgment and inhibition.
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Forebrain
The Thalamus is a large
structure of forebrain
that acts a routing
station or air-traffic
controller.
Processes sensory
information from the
CNS before it reaches the
cerebral cortex
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The Hypothalamus is a pea-sized
structure that controls many
complex behaviors such as eating,
drinking and sexual activity.
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This small structure regulates a
variety of complex behaviors. If you
have trouble remembering what this
structure does try this…
The FOUR F’s…
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Food
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Fight
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Flight
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And…Ummm….(Fornication?)
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Where do my emotions come from?
The limbic system is an interconnected
group of structures that are especially
significant in emotions, memory, and
social behavior.
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This is referred to as the “pleasure center”
of the brain
The limbic system also includes the
hippocampus and amygdala
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The Limbic System
Amygdala
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Can pleasure take us over?
YES! Research has shown that rats who
received electrical stimulation will repeatedly
press a lever which activates this regionproducing pleasure (Olds & Milner, 1954).
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The rats will choose to press the bar in preference
over food and water, eventually dying from
exhaustion!
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Recent research suggests that
there is a link between
addictive behaviors and the
stimulation of these areas
(Volvow et al., 2002).
Watch the following clip!
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Cerebral Cortex
The cerebral cortex is responsible for the most
complex mental activities including learning,
remembering, thinking, and consciousness
This area is made up of four lobes:
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Occipital Lobe
Parietal Lobe
Temporal Lobe
Frontal Lobe
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Four Lobes of the Brain
Parietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
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The Occipital Lobe
“Eyes in the back of
your head”
Responsible for
vision and visual
perception
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Parietal Lobe
Parietal Lobe is the area that is specialized
for the body senses and body image
The parietal lobe is involved with
processing information related to:
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Touch
Pain
Temperature
Awareness of the location of body parts
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Includes the Primary
Somatosensory Cortex, a band
of tissue on the front of the
parietal lobe
Each area of the primary somatosensory
cortex receives information about
touch in different body areas.
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What areas if the body have the most
cortex devoted to them?
Sensory
Homunculus
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As you can see from the
previous page the amount of
cortex that is devoted to each
body part is not equally
distributed
Larger areas are devoted to touch in the most sensitive
parts of the body such as lips and hands.
Smaller areas are devoted to touch in less sensitive
parts of the body such as the back and abdomen.
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Aren’t you glad your Somatosensory
cortex doesn’t match the outside?
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Temporal Lobe
The main processing area for hearing
Is the main processing area for some of
the complex aspects of vision
‐ Such as face recognition and motion
detection
Involved in aspects of learning, memory,
and emotions
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Frontal Lobe
Includes the Primary Motor Cortex, which
controls fine movements such as hand and
finger movements
Each area of the primary motor cortex
controls a different part of the body
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Larger areas are devoted to precise
movements of the tongue and fingers
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Smaller areas are devoted to movements of
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the shoulders and elbows
Once again, notice the
areas of the body that
have more motor
cortex devoted
Motor Homunculus
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If you want to see this in
action try the following.
Wiggle your fingers as fast as you can.
Now wiggle your toes…see the
difference? This is because you have
more motor cortex devoted to your
fingers than you do in your toes!
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Frontal Lobe Continued…
Includes the Prefrontal Cortex
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Critical for planning movements and
for certain aspects of memory,
problem solving, emotion, complex
thought
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Let’s test this…you’ll need
a watch or timer
Read the following words on the next
slide out loud- how fast can you do it?
Ready? GO!
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Stroop Test
Red
Yellow
Green
Green
Yellow
Yellow
Blue
Blue
Red
Red
Red
Green
Blue
Green
Blue
Green
Blue
Blue
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Pretty Easy, Right?
Now, read the word- NOT
the color
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Stroop Test
Red
Yellow
Green
Green
Yellow
Yellow
Blue
Blue
Red
Red
Red
Green
Blue
Green
Blue
Green
Blue
Blue
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A little bit harder, right?
Now, read the COLOR not the
Word
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Stroop Test
Red
Yellow
Green
Green
Yellow
Yellow
Blue
Blue
Red
Red
Red
Green
Blue
Green
Blue
Green
Blue
Blue
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SO, why did it get harder at
the end?
Most people will take longer to do the color
version than the black/white version. This is due
to concentration… much harder to say the color of
the word and not the word.
Word processing is much faster than color
processing. The conflicting word information
arrives as the decision process stage earlier than
the color information and results in confusion. 72
Congratulations! You have
finished learning about the
brain, which is no small feat.
Celebrate with a little humor in the
following video clip…also take note of
all the structures you should now be
familiar with!
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A Musical Brain Medley
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