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CHAPTER 2
BIOLOGICAL FOUNDATIONS IN
BEHAVIOR
BY
PAYAL JAIN
LEARNING OBJECTIVES
 Section
1: The Nervous System
 Section
2: The Brain: Our Control Center
 Class Exercise
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THE NERVOUS SYSTEM
•The nervous system functions
as a communication system for
the body. Messages are
transmitted by neurons to
axons and dendrites.
•The nervous system is made
up of the central nervous
system and the peripheral
nervous system, which
transmits messages between
the central nervous system
and all parts of the body.
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The Nervous system Cont.
The nervous system has two parts. The central nervous system consists of
the brain and spinal cord. The peripheral nervous system is made up of
nerve cells that send messages between the central nervous system and other
parts of the body. Nerve cells are called neurons.
Components of a Neuron
• The cell body produces energy
that fuels the neuron’s activity.
• Dendrites receive information
from other neurons and pass
the message through the cell
body.
• An axon transmits information
away from the cell body.
Components of a Neuron
(con’t)
• Myelin is a white, fatty
substance that covers the axon,
insulating and protecting it. The
myelin sheath helps to speed
up the work of neurons.
• Axon terminals branch out at
the end of the axon.
THE NERVOUS SYSTEM CONT.


Neural Messaging is an
Electrical and Chemical
Process.
The action potential is
how neurons send signals
down their axons
electrically.
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THE NERVOUS SYSTEM CONT.
•
Messages are sent from the axon terminals of one neuron to
the dendrites of another neuron.
•
In order for this process to happen, the message must cross
a synapse.
•
A synapse is a junction between the axon terminals of one
neuron and the dendrites of another.
•
Messages travel in only one direction. Messages
– enter the dendrites
–
travel through the cell body and axon to the axon
terminals
–
cross the synapses to the dendrites of other neurons
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Neurotransmitters: The Body’s Chemical
Messengers
• Neurons send messages across synapses through the release of
neurotransmitters.
• Neurotransmitters are chemicals that are stored in sacs in the axon
terminals.
• A neuron fires, or sends a message, by releasing neurotransmitters.
– The message is converted into an electrical impulse that travels through
the neuron.
– The message is transmitted to the next neuron by other
neurotransmitters until the message arrives at its destination.
• Human behaviours and emotions are modulated by neurotransmitters that act as
keys between neurons.
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Neurotransmitters: The Body’s Chemical
Messengers
Neurotransmitters: The Body’s Chemical
Messengers
THE NERVOUS SYSTEM CONT.
You need a cavity filled, so your dentist gives
you Novocain before he starts working on
your mouth.
 How does Novocain work to stop signaling
and prevent pain?

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The Central Nervous System
• The central nervous systems consists of the neurons of the spinal
cord and the brain.
• The spinal cord is a column of nerves about as thick as a thumb that
extends from the brain down the back.
• The spinal cord transmits messages between the brain and the
muscles and glands in the body.
• The spinal cord sends messages to specific muscles.
• The spinal cord is involved in spinal reflexes.
The Peripheral Nervous System
The Somatic Nervous
System
The Autonomic Nervous
System
• The somatic nervous system
transmits sensory messages to the
central nervous system.
• The autonomic nervous system
regulates the body’s vital functions,
such as heartbeat, breathing,
digestion, and blood pressure.
• It carries messages from the
voluntary muscles and sense
organs.
• It is activated by touch, pain,
changes in temperature, and
changes in body position.
• It has two divisions.
• The sympathetic nervous system
reacts to stress.
• The parasympathetic nervous
system restores peace to the
body’s systems
The Autonomic Nervous System
Section 2 at a Glance
The Brain: Our Control Center
• The brain is composed of three major sections: the
hindbrain, the midbrain, and the forebrain.
• The cerebral cortex is the part of the brain that controls
thinking, memory, language, emotions, complex motor
functions, perceptions, and much more.
Parts of the Brain
The Hindbrain
• The medulla is involved in heart rate, blood pressure, and breathing.
• The pons regulates body movement, attention, sleep, and alertness.
• The cerebellum is involved in balance and coordination.
The Midbrain
• Areas within the midbrain are involved in vision and hearing.
• Contains part of the reticular activating system, which is important
for attention, sleep, arousal, and alertness.
The Forebrain
• The thalamus serves a relay station for sensory stimulation.
• The hypothalamus is vital to the regulation of body temperature, the
storage of nutrients, and various aspects of motivation and emotion.
It is also involved in hunger, thirst, sexual behavior, caring for
offspring, and aggression.
• The limbic system is involved in learning and memory, emotion,
hunger, sex, and aggression.
• The cerebrum makes up about 70 percent of the brain’s weight and
is where most conscious and intellectual activities take place.
• The cerebral cortex is the outer layer of the brain. It is the part that
thinks, and it also deals with memory, language, emotions, complex
motor skills, perception, and more.
THE LIMBIC SYSTEM




Hypothalamus, pituitary,
amygdala, and hippocampus
all deal with basic drives,
emotions, and memory
Hippocampus  Memory
processing
Amygdala  Aggression
(fight) and fear (flight)
Hypothalamus  Hunger,
thirst, body temperature,
pleasure; regulates pituitary
gland (hormones)
Click on the image below to
play the Interactive.
The Cerebral Cortex
• The cerebral cortex has a left side and right side.
• Each side is called a hemisphere.
• The corpus callosum is the structure that connects the two
hemispheres.
• Information received by one side of the body is transmitted to the
opposite hemisphere of the brain.
• Each hemisphere is divided into four parts:
– frontal lobe
– parietal lobe
– temporal lobe
– occipital lobe
THE CEREBRAL CORTEX
Frontal
Lobes
 involved
in speaking and
muscle movements and in
making plans and judgments
 the “executive”
Parietal
 include
Lobes
the sensory cortex
THE CEREBRAL CORTEX
Occipital
Lobes
 include
the visual areas, which
receive visual information from
the opposite visual field
Temporal
 include
Lobes
the auditory areas, each of
which receives auditory
information primarily from the
opposite ear
PHINEAS GAGE
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The Amygdala Response
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The Amygdala Response
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AMYGDALA HIJACK
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AMYGDALA HIJACK
Where did my IQ Go?
Any strong emotion, anxiety, anger, joy, or betrayal trips off
the amygdala and impairs the prefrontal cortex’s working
memory. The power of emotions overwhelms rationality.
That is why when we are emotionally upset or stressed we
can’t think straight.
Example: Mike Tyson biting Evander Holyfield’s ear in their
1993 title boxing match. His hijack cost him $3million and
lost his boxing license
Eliot Spitzer, the governor of New York who made his name
as an aggressive prosecutor of corporate fraud and organized
crime had to resign in disgrace in 2008 for being personally
involved in a prostitution ring. These prostitutes charged up
to $3100 an hour.
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AMYGDALA HIJACK
1. What am I thinking? (Basal ganglia- integrates feelings,
thoughts and movements).
2. What am I feeling? (Basal ganglia- integrates feeling thoughts
and movements) Temporal Lobes – emotional stability, name it
to tame it – labeling affect.)
3. What do I want now? (Cerebellum – executive functions
connects to Prefrontol Cortex (PFC), cognitive integration).
4. How am I getting in my way? Prefrontal Cortex – learning
from mistakes.
5. What do I need to do differently now? (Prefrontal Cortex –the
boss supervision of life – executive functioning planning goal
setting, insight) (Anterior Cingulate Gyrus brain’s gear shifter–
sees options go from idea to idea).
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THE CEREBRAL CORTEX

Aphasia


Broca’s Area


impairment of language, usually caused by left hemisphere
damage either to Broca’s area (impairing speaking) or to
Wernicke’s area (impairing understanding) –see clips
an area of the left frontal lobe that directs the muscle movements
involved in speech
Wernicke’s Area

an area of the left temporal lobe involved in language
comprehension and expression
Reading Check
Summarize
What are the main functions of each part of
the cerebral cortex?
Answer: corpus callosum—connects two
hemispheres; occipital lobe—visual area; temporal
lobe—hearing, Wernicke’s area (connects sounds
and sights); sensory cortex in parietal lobe—
feeling (warmth, cold, touch, pain); frontal lobe—
”executive center,” Broca’s area (speaking)
CONTRA-LATERAL
DIVISION OF LABOR


Right hemisphere controls
left side of body and visual
field
Left hemisphere controls
right side of body and visual
field