Download The Nervous System, cont

Psychology
CHAPTER
4
The Brain and
Nervous System
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Study of the Brain
• Neuroscientists
– Study the brain and the rest of the nervous system in
hopes of gaining a better understanding of normal
behavior and of the outer reaches of what is possible
for this organ.
– Includes the study of the biological foundations of
consciousness, perception, memory, emotion, and
stress.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
The Nervous System
LO4.1 List the major parts of the human nervous system and describe their primary
functions.
• The nervous system: A basic blueprint
– Nervous system function: Gather and process
information, produce responses to stimuli, and
coordinate the workings of different cells.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
The Nervous System, cont’
LO4.1 List the major parts of the human nervous system and describe their primary
functions.
• The central nervous system
– Brain: Spinal cord
• A collection of neurons and
supportive tissue running from the
base of the brain down the center
of the back
• Protected by spinal column
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The Nervous System, cont’
LO4.1 List the major parts of the human nervous system and describe their primary
functions.
• The peripheral nervous system
– Handles the central nervous system’s
input and output
• Somatic nervous system
• Autonomic nervous
system
• Sympathetic nervous
system
• Parasympathetic
nervous system
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
The Nervous System, cont’
LO4.1 List the major parts of the human nervous system and describe their primary
functions.
• Organization
of the nervous
system
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System
LO4.2 Compare the functions of neurons and glial cells in the nervous system.
• Neurons
– The brain’s communication specialists, transmitting
information to, from, and within the central nervous
system.
• Glia
– Cells that provide support, nurture, and insulate
neurons, remove debris when neurons die, enhance
the formation and maintenance of neural connections,
and modify neuronal functioning.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.2 Compare the functions of neurons and glial cells in the nervous system.
• Types of neurons
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Communication in the Nervous System, cont’
LO4.3 Describe each of the three main parts of a neuron, and explain their functions.
• The structure of the neuron
– Dendrites
• Receive information from other
neurons and transmit it toward the
cell body.
– Cell body
• Keeps the neuron alive and
determines whether or not it will
fire.
– Axon
• Extending fiber that conducts
impulses away from the cell body
and transmits them to other
neurons.
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Communication in the Nervous System, cont’
LO4.3 Describe each of the three main parts of a neuron, and explain their functions.
• Myelin sheath
– Fatty insulation that may surround the axon of a neuron.
– Prevents signals in adjacent cells from interfering with
each other
– Speeds up the conduction of neural impulses
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.4 Explain how stem cells contribute to the process of neurogenesis.
• Neurogenesis: The birth of neurons
– Neurogenesis
• The production of new neurons from immature stem cells.
– Stem cells
• Immature cells that renew themselves and have the potential
to develop into mature cells.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.4 Explain how stem cells contribute to the process of neurogenesis.
• Stem-cell research
– Embryonic stem cells hold the promise of medical
advances, yet federal funding faces resistance from
some advocates.
– In recent years, scientists have successfully
reprogrammed cells from adult organs, most notably
skin cells, to become stem cells.
– Patient-advocacy groups hope that transplanted stem
cells will eventually help people recover from
diseases of the brain and from damage to the spinal
cord and other parts of the body.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.5 Outline the process by which neurons communicate with each other.
• How neurons
communicate
– Axon terminals
release neurotransmitter.
– Neurotransmitter
enters synapse.
– Neurotransmitter
binds to receptors
that it fits.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.5 Outline the process by which neurons communicate with each other.
• Action potential
– A brief change in electrical voltage that occurs
between the inside and outside of an axon when a
neuron is stimulated.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.5 Outline the process by which neurons communicate with each other.
• Neurotransmitter
– Chemical substance released by a transmitting neuron
at the synapse and that alters the activity of a
receiving neuron.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Communication in the Nervous System, cont’
LO4.6 Summarize the effects of some of the main neurotransmitters in the brain.
• Neurotransmitters
–
–
–
–
–
–
Serotonin
Dopamine
Acetylcholine
Norepinephrine
GABA (gamma-aminobutyric acid)
Glutamate
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Communication in the Nervous System, cont’
LO4.7 List four hormones that influence behavior, and describe the basic action of each
one.
• The endocrine system
– Endocrine glands release hormones into the
bloodstream.
– Hormones regulate growth, metabolism, sexual
development and behavior, and other functions.
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Communication in the Nervous System, cont’
LO4.7 List four hormones that influence behavior, and describe the basic action of each
one.
• The endocrine system
– Hormones
• Melatonin
 Regulates daily biological rhythms
• Oxytocin
 Secreted by the pituitary gland; enhances uterine contractions
during childbirth, facilitates ejection of milk during nursing
• Adrenal hormones
 Involved in emotions and stress
 Cortisol, epinephrine, and norepinephrine
• Sex hormones
 Regulate development and functioning of reproductive organs
 Androgens, estrogens, and progesterone
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Mapping the Brain
LO4.8 Describe eight techniques researchers use for understanding the workings of the
brain, and compare the strengths and limitations of each.
Intervening in the Brain and Observing Behavior
• Lesion method
– This is the removal or disabling of a brain structure to gain better
understanding of its function; this method is used only in
animals.
• Transcranial magnetic stimulation (TMS)
– A method of stimulating brain cells, using a powerful magnetic
field produced by a wire coil placed on a person’s head.
• Transcranial direct current stimulation (tDCS)
– A very small electric current is applied to an area of the cortex,
the outer surface of the brain. Depending on the direction of the
current, brain activity in that area is either temporarily stimulated
or suppressed.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Mapping the Brain
LO4.8 Describe eight techniques researchers use for understanding the workings of the
brain, and compare the strengths and limitations of each.
Intervening in Behavior and Observing the Brain
• Electroencephalogram (EEG)
– A recording of neural activity detected by electrodes.
• Alternatives to an electroencephalogram:
–
–
–
–
Event-related potentials (ERP)
PET scan (positron-emission tomography)
Magnetic resonance imaging (MRI)
Functional magnetic resonance imaging (fMRI)
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A Tour through the Brain
LO4.9 List and describe three main structures in the brain stem, and explain the primary
functions each structure performs.
• Brain stem
– Pons
Involved in sleeping, waking,
and dreaming
– Medulla
Responsible for certain
automatic functions, such as
breathing and heart rate
– Reticular activating
system
Arouses the cortex and
screens incoming information
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A Tour through the Brain, cont’
LO4.10 Describe the structure and function of the cerebellum.
• The cerebellum
– Regulates
movement and
balance
– Involved in
remembering
simple skills and
acquired reflexes
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A Tour through the Brain, cont’
LO4.11 Describe the structure, function, and location of the thalamus, hypothalamus,
pituitary gland, amygdala, and hippocampus.
• The thalamus
– Relays sensory
messages to the
cerebral cortex
– Includes all sensory
messages except
those from olfactory
bulb
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A Tour through the Brain, cont’
LO4.11 Describe the structure, function, and location of the thalamus, hypothalamus,
pituitary gland, amygdala, and hippocampus.
• The hypothalamus
and the pituitary
gland
– Involved in
emotions and drives
vital to survival
– Regulates
autonomic nervous
system
– Pituitary gland
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A Tour through the Brain, cont’
LO4.11 Describe the structure, function, and location of the thalamus, hypothalamus,
pituitary gland, amygdala, and hippocampus.
• The amygdala
– Responsible for
arousal, Regulation
of emotion, initial
emotional response
to sensory
information
– Plays important role
in mediating anxiety
and depression,
and emotional
memory
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A Tour through the Brain, cont’
LO4.11 Describe the structure, function, and location of the thalamus, hypothalamus,
pituitary gland, amygdala, and hippocampus.
• The hippocampus
– Responsible for
 Storage of new
information in memory
 Comparing sensory
information with what
the brain expects about
the world
 Enabling us to form
spatial memories for
navigating the
environment
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A Tour through the Brain, cont’
LO4.12 Describe the structure of the cerebrum, and explain the function of the corpus
callosum.
• The cerebrum
– Largest brain structure; two cerebral
hemispheres connected by the corpus
callosum (bundle of nerve fibers connecting
the two cerebral hemispheres)
– In charge of most sensory, motor, and
cognitive processes
– Surrounded by cerebral cortex, a collection of
several thin layers of cells (gray matter)
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
A Tour through the Brain, cont’
LO4.13 Sketch the location of each of the lobes of the cerebral cortex, and explain the
major functions each lobe performs.
• Lobes of the cerebral cortex
– Occipital lobes (visual cortex)
• Contain visual cortex
– Parietal lobes (somatosensory cortex)
• Pressure, pain, touch, and temperature
– Temporal lobes
• Memory, perception, and emotion
• Left lobe: Wernicke’s area
– Frontal lobes
• Emotion, planning, creative thinking, and take initiative
• Left lobe: Broca’s area
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A Tour through the Brain, cont’
LO4.13 Sketch the location of each of the lobes of the cerebral cortex, and explain the
major functions each lobe performs.
• Lobes
of the
cerebrum
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A Tour through the Brain, cont’
LO4.13 Sketch the location of each of the lobes of the cerebral cortex, and explain the
major functions each lobe performs.
• Phineas Gage
– Gage was a railroad construction foreman.
– An 1848 explosion forced a steel tamping
rod through his head.
– Others said he was “no longer Gage.”
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Two Hemispheres of the Brain
LO4.14 Discuss the basic format of a split-brain experiment, and describe what the
results of such experiments reveal about the functioning of the cerebral hemispheres.
• The two hemispheres of the brain
– The two hemispheres control opposite sides of the
body.
– If there is damage to the left hemisphere: May lose
ability to speak or understand language, difficulty
reading, identifying objects, making gestures,
describing events
– If there is damage to the right hemisphere: Difficulty
identifying faces, interpreting emotional expressions,
understanding music or art
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Two Hemispheres of the Brain
LO4.14 Discuss the basic format of a split-brain experiment, and describe what the
results of such experiments reveal about the functioning of the cerebral hemispheres.
• Split-brain experiment
– Patients were presented information to one or the
other side of their brains.
– Patients identified verbally the pictures to the right
(e.g., boy).
– When patients were asked to point to the face seen,
the patients pointed to the left picture.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Two Hemispheres of the Brain
LO4.14 Discuss the basic format of a split-brain experiment, and describe what the
results of such experiments reveal about the functioning of the cerebral hemispheres.
• Split-brain experiment
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
Two Hemispheres of the Brain
LO4.14 Discuss the basic format of a split-brain experiment, and describe what the
results of such experiments reveal about the functioning of the cerebral hemispheres.
• Two hemispheres: Allies or opposites?
– Research on split-brain patients shows us. . .
• Nearly all right-handed and the majority of lefthanded individuals process language mainly in the
left hemisphere.
• Many researchers believe in left-hemisphere
dominance.
• Others insist right hemisphere is important for
spatial visual problem solving, comprehending
non-verbal sounds, and some language abilities.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
The Flexible Brain
LO4.15 Define neural plasticity, and summarize some of the main evidence that the brain
has the ability to change in response to new experiences.
• Plasticity
– The brain’s ability to change and adapt in
response to experience, through
neurogenesis, or by reorganizing or growing
new neural connections.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.
The Flexible Brain, cont’
LO4.16 Summarize five cautions surrounding whether sex differences in anatomical brain
size are linked to sex differences in behavior.
• “His” and “her” brains?
– Yes, there are differences between men’s and
women’s brains.
– There do appear to be sex differences in
lateralization of the amygdala.
• Men’s right amygdala gets continual input from the
rest of the brain.
• Females get continual input from the left
amygdala.
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The Flexible Brain, cont’
LO4.16 Summarize five cautions surrounding whether sex differences in anatomical brain
size are linked to sex differences in behavior.
• What do differences mean for behavior?
– Supposed differences are stereotypes.
– Brain difference does not necessarily explain
behavior or performance.
– Brain difference does not account for differences in
behavior across situations.
– Sex differences in the brain could be the result rather
than the cause of behavioral differences.
– Studies of the brain difference focus on different
areas.
© 2014, 2011, 2008 by Pearson Education, Inc. All rights reserved.