Transcript The Biology of Behavior

The Brain and our
Nervous System
CHAPTER 4
Objectives
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Gain a general understanding of the
nervous system
Gain knowledge of the structure and
function of the neuron
Navigate your way around the major brain
areas and understand their function
Nervous System Hierarchy
Central nervous system
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Brain
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~2% of body weight, uses ~20% of resources
Composed of bunches of neurons, which form
nerves
Spinal cord
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Complex tangle of nerves that stretch from
brain to tailbone
Collects & transmits info between brain and
peripheral nervous system
Also initiates reflexes: automatic responses to
an event
Peripheral Nervous System
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PNS links the CNS to the organs, muscles,
and glands of the body
PNS has two parts
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Somatic (SNS): nerves controlling voluntary
muscle movements
Autonomic (ANS): controls glands, organs,
blood vessels
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ANS has two parts
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Sympathetic: arouses body to prepare for action (fight or
flight)
Parasympathetic: slows down body to reserve energy
Sympathetic and Parasympathetic
The Neuron
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All brain activity originates with the neuron
The messengers of the brain-world
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Three types
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These cells receive signals from neurons or sense
organs, process the signals, and send them to other
neurons, muscles, or organs
Sensory: respond to sensory organ input
Motor: send signals to muscles to control movement
Interneurons: the go-between of sensory and motor
neurons
We have about 100 billion neurons
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Most, but not all, can be re-grown (severe spinal cord
injury vs. cutting your finger)
The Neuron
The Neuron: Structure
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Cell body: houses nucleus
Cell Membrane: skin of the cell
Axon: cable extending from the cell body
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Impulse from cell body travels along axon to its end,
where terminal buttons release neurotransmitters
(chemical messengers), received by other neurons
Axon is covered by myelin sheath, which is composed
of a fatty substance that helps impulses travel the
length of the axon
Dendrite
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Branches extending from cell membrane that receive
neurotransmitters from other neurons
The Dendrite
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Increases receptive surface of the neuron
Contacts occur along surface of dendrite
The Axon
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Axon hillock
Myelin sheath
Nodes of
Ranvier
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The points
just between
the myelin
sheaths
The Synapse
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At the end of
the Axon
Releases
neurotransmitters
through the
vesicles to
the receptors
on the
dendrite of
the other
axon
The Neuron in Action
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When a neuron receives impulses from
other neurons, the cell membrane allows
open exchange of positively and negatively
charged ions
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Action potential (change in electrical charge)
runs down axon to terminal buttons
This all starts with the axon hillock – the
gatekeeper of the neuron
Terminal buttons release neurotransmitters
Neurotransmitters cross the synaptic cleft to
the dendrite of the receiving neuron
The Neuron in action
Several Neurotransmitters
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Acetylcholine (Ach)
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Dopamine (DA)
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Reduce sensitivity to pain; linked with pleasure (opiate-like)
Serotonin
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Voluntary movement, attention, and learning; high levels are
associated w/ schizophrenia
Endorphin
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Slows down the body, memory, and attention (involved in
Alzheimer’s disease)
Arousal, sleep; Prozac increases levels of serotonin
Norepinephrine
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Helps control alertness and arousal; low levels can depress
mood
Brain Dominance
Questionnaire
Take a plain sheet of paper and
number it 1 to 15. For each
question you will choose
a, b, or c.
Brain Dominance Questionnaire
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1) I prefer to learn
A.
B.
C.
Details and specific facts
From a general overview of things, and by
looking at the whole picture
Both ways about equally
Brain Dominance Questionnaire
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2) I prefer the jobs
A.
B.
C.
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Which consist of one task at a time, and I
can complete it before beginning the next
one.
In which I work on many things at once.
I like both kinds of jobs equally.
3) I prefer to solve problems with
A.
B.
C.
Logic
My “gut feelings”
Both logic and “gut feelings”
Brain Dominance Questionnaire
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4)
Planned so that I know exactly what to do
B.
Open with opportunities to change as I go along
C.
Both planned and open to change
5) I like to learn a movement in sports or a dance step
better by
A.
Hearing a verbal explanation and repeating the
action or step mentally
B.
Watching and then trying to do it again
C.
Watching and then imitating and talking about it.
A.
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I like my work to be
Brain Dominance Questionnaire
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6) I remember faces easily
A.
B.
C.
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No
Yes
Sometimes
7) If I have to decide if an issue is right
or correct
A.
B.
C.
I decide on the basis of information
I instinctively feel it is right or correct
I tend to use a combination of both
Brain Dominance Questionnaire
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8) I prefer
Multiple-choice tests
B.
Essay tests
C.
I like both kinds of tests equally
9) If I had to assemble a bicycle, I would most likely
A.
Lay out all of the parts, count them, gather the
necessary tools, and follow directions.
B.
Glance at the diagram and begin with whatever tools
were there, sensing how the parts fit.
C.
Recall past experiences in similar situations.
A.
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Brain Dominance Questionnaire
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10) At school, I preferred
A.
B.
C.
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Algebra
Geometry
I had no real preference for one over the
other
11) It is more exciting to
A.
B.
C.
Improve something
Invent something
Both are exciting to me
Brain Dominance Questionnaire
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12) I generally
A.
Use time to organize work and personal
activities.
B.
Have difficulty in pacing personal activities in
time limits.
C.
Am able to pace personal activities to time limits
with ease.
13) Daydreaming is
A.
A waste of time.
B.
A usable tool for planning my future.
C.
Amusing and relaxing.
Brain Dominance Questionnaire
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14) I can tell fairly accurately how much
time has passed without looking at a clock
A.
B.
C.
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Yes
No
Sometimes
15) When reading or studying, I
A.
B.
C.
Prefer total quiet
Prefer music
Listen to background music only when reading
for enjoyment, not while studying.
Scoring Instructions
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Calculate the number of your “A” and “B”
answers. Do not consider your “C” answers.
Put a (-) minus sign in front of your “A”
score and a (+) plus sign in front of your
“B” score.
Do the algebraic sum off your “A” and “B”
scores.
Scores
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-15 to -13
-12 to -9
-8 to -5
-4 to -1
0
+1 to +4
+5 to +8
+9 to +12
+13 to +15
Left brain dominant (Very Strong)
Left brain dominant
Moderate preference for the left
Slight Preference for the left
Whole brain dominance
Slight preference for the right
Moderate preference for the right
Right brain dominant
Right brain dominant (Very Strong)
The Brain (Day 2)
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Three main parts
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Brain Stem
Limbic System
Cerebral Cortex
Areas of the Brain
Brain Stem
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Region of the brain where the spinal cord
enters the skull and swells
Medulla
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Regulates heart-rate, breathing, blood
pressure, and motor movements
Cerebellum
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Controls skilled motor movements
Brain Stem
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Pons
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Reticular formation
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Connects the two hemispheres of the
cerebellum
Sleep (Moruzzi & Magoun, 1961)
Attention
Thalamus
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Relay center
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Filters & organizes information from senses
Limbic System
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Hypothalamus
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Feeding
Reproductive behavior
Temperature (Barbour, 1912)
Hippocampus
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Memory
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H.M.
Amygdala
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Feeding
Memory
Emotion
Cerebral Cortex
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Two halves, four lobes
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Frontal lobe
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Motor cortex
Parietal lobe
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Sensory cortex
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Temporal lobe
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Prosopagnosia
Unilateral neglect
Auditory areas
Occipital lobe
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Visual areas
Two Cerebral Hemispheres
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Contralateral arrangement
Corpus callosum
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Thick band of nerve fibers connecting the
hemispheres
It’s how the 2 hemispheres communicate
Right-brained vs. left-brained?
OR
Left & Right Functions