Download PSYC 100 Chapter 2

Chaffee Winter 2013
CHAPTER 2
Psychology 100: General Psychology
WEEK 2 ASSIGNMENTS
Read Chapter 2: The Biology of the Mind
It is impossible to be successful in the field of
psychology without understanding the basics of
neuronal communication. Please contact me if you
have difficulty with this chapter.
When studying the material, and the parts of the brain
outlined in this chapter, try to remember structure
and function. Be able to name the structure and state
its function.
Chaffee Winter 2013
This chapter is much more complicated than the
previous chapter, yet it provides a remarkable
introduction to the nervous system
CHAPTER 2: THE BIOLOGY OF MIND
  Neural
 
 
Neurons
How Neurons Communicate
Neurotransmitters
  The
 
 
Nervous System
Peripheral Nervous System
Central Nervous System
  The
Endocrine System
  The Brain
 
 
 
 
Older Brain Structures
The Cerebral Cortex
Our Divided Brain
Right-Left Brain Differences
Chaffee Winter 2013
 
Communication
INTRODUCTION
  “Everything
psychological is
simultaneously
biological” (Myers, 2010, p. 47).
  Phrenology was a popular
theory in the 1800s, invented
by Franz Gall
 
 
Bumps on the skull could reveal
brain functioning
Although this theory was false,
it did correctly assume the brain
has regions with different
functions
NEURAL COMMUNICATION
 
Neuron: a nerve cell, building block of the nervous system
 
 
 
 
 
 
Myelin sheath: a layer of fatty tissue segmentally encasing the
fibers of many neurons; enables vastly greater transmission
speed of the neural impulse
Action Potential: a neural impulse; the brief electrical charge
that travels down an axon
Chaffee Winter 2013
 
Sensory neuron: carries information from the sensory receptors to
the brain and spinal cord
Motor neuron: carries outgoing information from the brain and
spinal cord to the muscles and glands
Interneuron: neurons within the brain and spinal cord that
communication internally and intervene between the sensory
inputs and motor outputs
Dendrite: a branching extension of a neuron that receives
information and conducts impulses toward the cell body of the
neuron
Axon: an extension of the neuron through which messages are
passed to other neurons or muscles and glands
NEURAL COMMUNICATION (FIGURE 2.2)
THE ACTION POTENTIAL
An action potential is a brief electrical charge that
travels down the axon, which is triggered by chemical
signals from neighboring neurons.
  The purpose of the action potential is to continue that
signal down the axon to the axon terminal
  The axon terminal is located at the synapse, or the
junction between the axon tip of the sending neuron
and the dendrite or cell body of the receiving neuron.
The tiny gap at this junction is called the synaptic
cleft.
  As the action potential reaches the synapse, it
stimulates the release of neurotransmitter
molecules. These molecules are released into the
synaptic cleft and may bind to receptor sites at the
next neuron.
 
Chaffee Winter 2013
HOW NEURONS COMMUNICATE (FIG 2.4)
Chaffee Winter 2013
HOW NEURONS COMMUNICATE CONTINUED
 
Neurotransmitters:
 
 
By binding the receiving neuron, neurotransmitters
influence the likelihood that receiving neuron will
generate a neural impulse.
 
 
 
Excitatory neurotransmitters increase the likelihood the
impulse
Inhibitory neurotransmitters decrease the likelihood of the
neural impulse
Reuptake: Allows the sending neuron to reabsorb
the excess neurotransmitter in the synaptic cleft.
Chaffee Winter 2013
 
Chemical messengers that cross the synaptic gaps between
neurons.
Neurotransmitters travel across the synapse and bind to
the receptor sites on the receiving neuron.
RECAP: NEURONAL COMMUNICATION
MATCH THE TERMS AND DEFINITIONS
A. 
Axon
2. 
Dendrite
3. 
Myelin
4. 
Synapse
5. 
Neurotransmitter
6. 
Reuptake
F. 
7. 
Action Potential
G. 
B. 
C. 
D. 
E. 
Chaffee Winter 2013
1. 
The junction between the axon tip of
the sending neuron and the dendrite or
cell body of the receiving neuron
an extension of the neuron through
which messages are passed to other
neurons or muscles and glands
enables vastly greater transmission
speed of the neural impulse
branching extension of a neuron that
receives information and conducts
impulses toward the cell body of the
neuron
the brief electrical charge that travels
down an axon
chemical messengers that cross the
synaptic gaps between neurons
Reabsorbing of excess neurotransmitter
molecules in the synaptic cleft
HOW NEUROTRANSMITTERS INFLUENCE US
 
Drugs and other chemicals can affect the brain at the synapse,
acting like a neurotransmitter.
Chaffee Winter 2013
 
The process by which neurotransmitters influence us is complex,
involving pathways of neural activity within the brain.
HOW NEUROTRANSMITTERS INFLUENCE US
Chaffee Winter 2013
THE NERVOUS SYSTEM
THE NERVOUS SYSTEM
Chaffee Winter 2013
The Nervous System: The body’s electrochemical
communication network, consisting of the nerve cells
of the peripheral and central nervous systems.
  Central Nervous System (CNS): brain and spinal
cord
  Peripheral Nervous System (PNS): sensory and
motor neurons that connect the CNS to the rest of
the body
  Nerves: bundles of axons that form neural “cables”
connecting the central nervous system with muscles,
glands, and sense organs
THE PERIPHERAL NERVOUS SYSTEM
 
 
 
The Autonomic Nervous System is divided into two
subdivisions.
The Sympathetic Nervous System
The Parasympathetic Nervous System
Chaffee Winter 2013
Our peripheral nervous system (the sensory and
motor neurons that connect the CNS to the rest of
the body) has two components:
1.  Somatic Nervous System: the division of the
PNS that controls the body’s skeletal muscles
2.  Autonomic Nervous System: the part of the
PNS that controls the glands and the muscles of
the internal organs.
THE NERVOUS SYSTEM
Chaffee Winter 2013
SYMPATHETIC AND PARASYMPATHETIC
DIVISIONS OF THE AUTONOMIC NERVOUS
SYSTEM
 
 
Sympathetic nervous
system: division of the
autonomic nervous system
that arouses the body,
mobilizing its energy in
stressful situations (fight or
flight)
Parasympathetic nervous
system: division of the
autonomic nervous system
that calms the body,
conserving its energy
THE ENDOCRINE SYSTEM
  The
 
Hormones: chemical messengers that are manufactured
by the endocrine glands, travel through the blood stream,
and affect other tissues including the brain
  The
endocrine system and nervous system both
produce molecules that act on receptors elsewhere.
The nervous system sends fast messages while the
endocrine system sends slower messages, but their
effects can last longer.
 
Brain  Pituitary  other glands  Hormones  Brain
Chaffee Winter 2013
body’s “slow” chemical communication system; a
set of glands that secrete hormones into the
bloodstream
THE ENDOCRINE SYSTEM
Chaffee Winter 2013
THE ENDOCRINE SYSTEM CONTINUED
 
The pituitary gland is a pea-sized structure located
in the core of the brain
 
 
 
 
The pituitary gland is controlled by the hypothalamus, an
area of the brain located directly above the pituitary.
The pituitary secretes hormones that influence the release
of hormones by other endocrine glands
E.g. the hypothalamus stimulates the pituitary to trigger
the sex glands to release sex hormones. These hormones
then influence the brain and behavior.
Brain  Pituitary  other glands  Hormones  Brain
Chaffee Winter 2013
 
The adrenal glands are a pair of endocrine glands
that sit above the kidney. They secrete epinephrine
and norepinephrine that help around the body in
times of stress
THE BRAIN: THE TOOLS OF DISCOVERY
  Types
 
 
 
Electroencephalogram (EEG): a technique for the
study of electrical current, or activity, within the
brain.
Positron emission tomography (PET): A highly
specialized imaging technique that uses short-lived
radioactive glucose to produce three-dimensional
colored images of those substances functioning within
the brain, such as during a task
Magnetic Resonance Imaging (MRI): a technique that
uses magnetic fields and radio waves to produce
computer-generated images of soft tissue
Functional MRI (fMRI): a technique for revealing
blood flow, and thus brain activity, by comparing
successive MRI scans
Chaffee Winter 2013
 
of Imaging
THE BRAIN: OLDER STRUCTURES
These structures are called “older” by the book as
they are present in primitive animals, such as the
shark, with a much longer history on earth than homo
sapiens. The older brain structures control more basic
functions, such as breathing.
  The brainstem is the oldest part of the brain,
beginning where the spinal cord enters the skull. It is
responsible for automatic survival functions
 
 
 
The medulla is located at the base of the brainstem. It
controls heartbeat and breathing.
The pons is another area of the brainstem that helps
coordinate movements.
Within the brainstem is a neural network known as
the reticular formation. These neurons control
arousal, or alertness.
Chaffee Winter 2013
 
THE BRAIN: OLDER STRUCTURES
OLDER STRUCTURES CONTINUED
  The
thalamus is located on
top of the brainstem; it
directs sensory information
and motor signals from the
brainstem to the cerebral
cortex; also, it transmits
information from the cortex
to the cerebellum and
medulla
  The cerebellum processes
sensory input, coordinates
motor output, and assists in
balance
THE LIMBIC SYSTEM
Chaffee Winter 2013
The limbic system is a
neural network located
underneath the cerebral
hemispheres, associated
with emotions, motives,
and drives
AMYGDALA
  The
amygdala, composed of
two structures shaped like
almonds (one in each
hemisphere), functions to
regulate aggression, fear,
and emotion
  Kluver-Bucy syndrome:
 
 
Remove amygdala in primates
Result: mellow, difficulty
recognizing objects,
hypersexual, and displayed
hyperorality
THE HYPOTHALAMUS
  Hypothalamus:
a neural
structure lying below the
thalamus
 
 
 
 
helps govern the endocrine system
via the pituitary
directs maintenance activities:
eating, drinking, temperature
regulation
Neural networks for emotion and
reward
The four Fs (fight, flight, feeding,
sex)
HIPPOCAMPUS
The hippocampus is the third area of the limbic
system, as defined by this book.
  Functions:
 
 
 
Formation of new memory (first part affected by Alzheimer’s
disease)
Emotions, vulnerable to stress
Spatial memory and navigation
Chaffee Winter 2013
 
THE CEREBRAL CORTEX
THE CEREBRAL CORTEX: STRUCTURE
  The
 
 
 
 
The folds of the cortex increase surface area, thus
allowing more neurons to fit within the skull.
If you were to flatten the cerebral cortex, the brain
would require triple the area.
The degree of cortical folding indicates the complexity
of cortical functions that are possible.
Consider the differences in cortical folds in different
animals, see next slide.
Chaffee Winter 2013
cerebral cortex is the intricate fabric of
interconnected neural cells covering the cerebral
hemispheres; the body’s ultimate control and
information-processing center.
  Cortical Folds:
THE CEREBRAL CORTEX: COMPARATIVE
NEUROANATOMY
STRUCTURE OF THE CORTEX
  The
2. 
3. 
4. 
Chaffee Winter 2013
1. 
brain is divided into four areas called lobes
Frontal Lobes: Portion of the cerebral cortex
lying just behind the forehead; involved in
speech, motor functioning, and higher order
thought such as planning, judgment, decision
making
Parietal Lobes: receives sensory input
Temporal Lobes: auditory processing, speech
Occipital Lobes: receives input from visual
fields
FUNCTIONS OF THE CORTEX: MOTOR
 
Chaffee Winter 2013
 
The motor cortex is located at the rear (posterior) portion of the
frontal lobes and it controls voluntary movements
The motor cortex controls contralateral movement, meaning the
movement on the opposite site of the body.
MOTOR CORTEX: NEURAL PROSTHESIS
  As
you can see from the figure on the previous
slide, the motor cortex has been mapped
Guided by a 100-electrode
brain implant, this
monkey learned to control
a mechanical arm that
can grab snacks and put
them in his mouth
(Velliste et al., 2008).
This research raises hope
for the use of neural
prosthetics in people with
paralyzed limbs.
FUNCTIONS OF THE CORTEX: SENSORY
  The
sensory cortex is
located at the front of the
parietal love. It registers and
processes body touch,
movement, and position
information.
  The visual cortex of the
occipital lobe receives visual
input from your eyes.
  The auditory cortex of the
temporal lobes receives
auditory information from
your ears.
FUNCTIONS OF THE CORTEX: ASSOCIATION
 
Chaffee Winter 2013
 
The areas of the cerebral cortex that are not involved in primary motor
or sensory functions, but rather in higher mental functions such as
learning, remembering, thinking and speaking, are known as
association areas.
More “intelligent” animals have more association areas of their cortex.
These areas are responsible for integrating and acting on information
received and processed by sensory areas.
ASSOCIATION AREAS CONTINUED
  The
association areas of the frontal lobe enable
judgment, planning, and processing of new
memories. Damage to the frontal lobe can alter
the capacity to make plans and can even change
personality.
  Read the story of Phineas
Gage, starting on page 72.
THE BRAIN
Chaffee Winter 2013
THE BRAIN’S PLASTICITY
 
 
 
 
Severed neurons do not regenerate, but some neural tissue
can reorganize in response to damage.
In the case of blind or hearing impaired individuals, the
unused brain areas are available for other uses. For
example, when a blind person reads Braille, the brain area
dedicated to that finger expands as areas of the visual
cortex are activated (Baringa, 1992; Sadato et al., 1996).
Neurogenesis, or the formation of new neurons, can
also occur after damage. However, new neurons are
only formed deep within the brain and must migrate
elsewhere and form connections (Gould, 2007).
Chaffee Winter 2013
The brain’s ability to change, especially during
childhood, by reorganizing after damage or by
building new pathways based on experience, is known
as plasticity.
OUR DIVIDED BRAIN
 
 
The left and right hemisphere of the brain are largely separate.
Chaffee Winter 2013
The corpus callosum is a large band of neural fibers
connecting the two brain hemispheres and carrying messages
between them
RIGHT-LEFT DIFFERENCES IN THE INTACT
BRAIN
  Lateralization:
the specialization of certain functions
by each side of the brain
 
One side tends to be dominant in each activity
The Whole Brain
Left brain
Right side of body
Serial processor (Linear thought)
Logical reasoning, detailed analysis, basics of
language
Right brain
Left side of body
Parallel processor (Conscious, complex thought)
Emotional and creative processes
VIDEO: STROKE OF INSIGHT
 
 
 
 
 
Each time one of these short talks is assigned, your goal is to
find a “take-home” message from the information presented.
On exams, you will be asked what your “take-home” message
was from the talk, and I expect you to provide a short
paragraph (more than 1 sentence) that reflect your knowledge
of the material presented by the speaker and your opinion on
the topic.
Watch this 18 minute presentation: http://www.ted.com/
talks/jill_bolte_taylor_s_powerful_stroke_of_insight.html
Jill Bolte-Taylor, the speaker, is a renowned neuroscientist.
The video describes her experience of a cerebral
hemorrhage, or stroke, and her recovery.
Chaffee Winter 2013
Throughout the course, we will watch several Ted Talks,
short lectures, from leading researchers. Visit http://
www.ted.org and note the purpose of this organization to
provide “Riveting talks by remarkable people, free to the
world.”
CHAPTER 2 LEARNING OBJECTIVES
 
 
 
Chaffee Winter 2013
 
Neural Communication
1. 
Describe a neuron, including its major parts.
2. 
Describe an action potential, synapse, and neurotransmitter.
The Nervous System
1. 
Distinguish the central and peripheral nervous system.
2. 
Distinguish the subdivisions of the peripheral nervous system.
3. 
Distinguish the sympathetic and parasympathetic divisions of the
autonomic nervous system.
The Endocrine System: What are hormones? Describe their path from the
brain to the body, and back.
Describe the major divisions of the brain as discussed in your text:
1. 
Older structures: Brainstem
2. 
Limbic System: Hypothalamus, Amygdala, Hippocampus
3. 
Know the four main divisions of the cortex.
4. 
Describe plasticity and neurogenesis
5. 
What is the corpus callosum? How are the left and right
hemispheres different? Take-home message from Jill Bolte-Taylor
presentation.