Download IV. PSYCHOBIOLOGY

IV. Neuroscience
The relationship between brain
and behavior.
A. Earliest work...
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Brain/body and behavior connection.
– Hippocrates: brain injury and behavior
– Phrenology (Franz Gall – 1800’s)
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What does your skull say about you?
B. The body’s basic communication network.
 The
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1. “Communication system”.
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nervous system:
Encounter a bear in the woods.....
Coordinates the body and environment.
– “Electrochemical”
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receives messages
organizes messages
sends out messages
B. The body’s basic communication
network.
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2. Two components:
– a. Central Nervous System (CNS)
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Brain and spinal cord.
B. The body’s basic
communication network
2. Two components:
– b. Peripheral Nervous System.
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Connects CNS with rest of body.
Controls skeletal movement and internal
organs.
Nervous System
Nervous
system
Central
(brain and
spinal cord)
Peripheral
Autonomic (controls
self-regulated action of
internal organs and glands)
Skeletal (controls
voluntary movements of
skeletal muscles)
Sympathetic
(arousing)
Parasympathetic
(calming)
C. Basic Building Blocks of Neural
Communication

THE NEURON
– Nerve or Neuron?
– A neuron is a single nerve cell
– A nerve is a bundle of neurons
Nerve cell - most basic component.
Information carrier and integrator.
“Talks” to other cells, muscles, etc.

1. 3 different kinds of neurons:
– Sensory:
– Interneuron:
– Motor:
receiving
organizing
sending
2. Structure of a Neuron
C. Basic Building Blocks of
Neural Communication

2. Structure of neuron:
– Dendrites receive signals.

Carry info to cell body.
– Cell body synthesizes these signals.
– Signal travels down axon.

Away from cell body.
– Helped along by myelin sheath.

Made up of glial cells.
C. Basic Building Blocks of Neural
Communication
3. How neurons communicate.
 a. Chemistry-to-electricity process.
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– Within neuron part:
– Neuron at rest – electrically charged.

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Resting potential.
Ions exist outside/inside of cell membrane.
More negative ions inside of membrane.
– Gets stimulated (by light, heat, pressure,
chemicals from other neurons).
C. Basic Building Blocks of
Neural Communication
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3. How neurons communicate (with neuron).
a. Chemistry-to-electricity process.
– Positive ions move into cell – if strong enough –
causes depolarization

FIRES!
– But – strong enough means must reach:
– Threshold 
– Fires signal/electric impulse down axon 

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called Action potential.
“All-or-none process”
C. Basic Building Blocks of
Neural Communication
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3. How neurons communicate.
b. Importance of neurotransmitters.
(Between neuron communication).
Synapse: Junction between axon tip of sending
neuron and dendrites of receiving neuron.
Synaptic Gap - tiny gap between neurons.
Action potential fires, travels down axon – releases 
Neurotransmitters - chemical messengers 
cross the synaptic gap, binds to sites on receiving
neuron.
3. How neurons communicate

a. Importance of Neurotransmitters.
Found in different places, do different jobs.
- Acetylcholine (learning, memory, muscle contraction,)
- Endorphins (mood/pain)
- Dopamine (smooth movement)
- Norepinephrine (alertness, arousal)
- Serotonin (mood, hunger, sleep)
3. How neurons communicate
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c. Neurotransmitters and drugs.
Agonist: EXCITES.
Drug/toxin mimics the effects of
neurotransmitter, or heightens activity of
neurotransmitters.
Antagonists: INHIBITS
Drug/toxin that inhibits or blocks release of
neurotransmitters.
Examples:
Influence of drugs on
neurotransmitters:
 Importance of REUPTAKE.

– Agonists heighten neurotransmitter activity
by blocking reuptake of the chemical.
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Examples: Cocaine
COCAINE
D. Brain
2. Structure
 a. Lower Level
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– Brainstem: oldest, innermost region
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controls arousal.
– Thalamus: “switchboard”
– Cerebellum: little brain
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coordinates movement and balance
The Brain
2a. Lower level brain structure
– Limbic system:
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amygdala - aggression, fear
hypothalamus - hunger, thirst, sexual behavior.
– “reward center”
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hippocampus - memory.
The Limbic System
2. Structure of brain:
a. Lower Level
2. Structure of Brain:
b. Cerebral Cortex

1. “Bark” of the brain
2. Structure of Brain:
b. Cerebral Cortex
2. Function of 4 Lobes:
Frontal: Motor Cortex
Specific areas stimulate movement.
Parietal: Sensory Cortex
Receives information from skin and
body parts (touch/movement).
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2. Structure of Brain:
b. Cerebral Cortex
2. Functions of 4 Lobes, cont’d.
Occipital: processes visual information,
sends it elsewhere to be decoded.
Temporal: processes sound.

Sensory and motor cortex, and visual and
auditory areas take up 1/4 of brain.
2. Structure of Brain:
b. Cerebral Cortex
Association Areas:
Other “3/4” of cerebral cortex.
Integrates, interprets, acts on information.
(i.e. important to communication).
Areas and their associated behaviors have
been identified based on what happens
when those areas are damaged.
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B. Association Areas
Frontal Lobe:
- cannot plan or judge.
- alters personality - Phinneas Gage
- speech production- Broca’s Area
Temporal Lobe:
- can’t recognize faces.
- speech understanding - Wernicke’s Area
C. Two Hemispheres of Brain
Brain’s sides (left and right) serve
different purposes.
 Stroke?
 Damage to left side - reading, writing,
speaking, understanding.
- considered “major”, verbal hemisphere
 Damage to right side - not as dramatic
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C. Two Hemispheres of Brain
Corpus callosum

Important - how sides
communicate with each
other.
– Corpus Callosum: bundle
of neural fibers
connecting both sides,
carries messages
between them.
– If severed, demonstrates
how both sides work
together.
c. Two Hemispheres of Brain
Talents of each hemisphere.
Right: perceptual

picture recognition
emotion, expression, creativity
Left: speaking, calculating numbers
word recognition
analytical, logical
Conclusions
There is no psychology without biology.
 From the neuron to the brain:

– How information/stimuli are taken in,
integrated, and responses (behavior) are
generated based on the body’s
communication system – nervous system.
Neural Systems
Neurons in the brain
connect with one
another to form networks
The brain learns by modifying
certain connections in
response to feedback
Neural Networks
interconnected neural
cells
with experience,
networks can learn