Download The basics of brain communication

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Biology and Behavior
3.1
How does the Nervous System Operate?
• The Nervous System has Two Basic Divisions
• Neurons are Specialized for Communication
• The Resting Membrane Potential Is Negatively Charged
• Action Potentials Cause Neural Communication
• Neurotransmitters Bind to Receptors Across the Synapse
• Neurotransmitters Influence Mental Activity and Behavior
3.2
What are the Basic Brain Structures and Their Functions?
• Scientists Can Now Watch the Working Brain
• The Brain Stem Houses the Basic Programs of Survival
• The Cerebellum is Essential for Movement
• Subcortical Structures Control Emotions and Appetitive Behaviors
• The Cerebral Cortex Underlies Complex Mental Activity
• Splitting the Brain Splits the Mind
• What to Believe? Using Psychological Reasoning: Failing to Notice
Source Credibility: Are There “Left Brain” and “Right Brain” Types of
People?
3.3
How Does The Brain Communicate with the Body?
• The Peripheral Nervous System Includes the Somatic and Autonomic
Systems
• The Endocrine System Communicates through Hormones
• Actions of the Nervous System and Endocrine System Are Coordinated
3.4
How Does the Brain Change?
• Experience Fine-Tunes Neural Connections
• Females’ and Males’ Brains Are Mostly Similar but May Have Revealing
Differences
• The Brain Rewires Itself Throughout Life
• The Brain Can Recover from Injury
3.5
What is the Genetic Basis of Psychological Science?
• All of Human Development Has a Genetic Basis
• Heredity Involves Passing Along Genes Through Reproduction
• Genotypic Variation is Created by Sexual Reproduction
• Genes Affect Behavior
• Social and Environmental Contexts Influence Genetic Expressions
• Genetic Expression Can Be Modified
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The Neuron: The Basic Unit of Communication
Neuron: The basic units of the nervous system; cells that
receive, integrate, and transmit information in the nervous
system. They operate through electrical impulses,
communicate with other neurons through chemical
signals, and form neural networks. (page 76).
Neuron Structure
(see Figure 3.5 on page 79)
image source: Gazzaniga, Heatherton, Halpern, Psychological Science (2016).
There are approximately 100 billion neurons in the brain.
(100 billion = 10x1011 = 100,000,000,000)
How small is the synaptic gap?
• The synaptic gap (the space between synapses) is
about 5/1,000,000 of an inch.
It takes about 10/1,000,000 of a second to cross this gap
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To get a feel for how small this is, make the following
analogy:
1 ream of paper =
2,000 reams
=
500 pages
=
2 inches
1,000,000
pages
= 4,000 inches or
111 yards
One football field (without the end zones) is 100 yards.
.
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How do these neurons communicate with each other?
Figure 3.5, page 79
image source: Gazzaniga, Heatherton, Halpern, Psychological Science (2016).
Figure 3.8, page 83
image source: Gazzaniga, Heatherton, Halpern, Psychological Science (2016).
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Communication Between Neurons
When communication has occurred, the neurotransmitters
are either:
(1) broken down by enzymes and removed from the
brain.
(2) go through a reuptake process to be reused in the
presynapse.
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Neurotransmitters
The main neurotransmitters
• Serotonin
• Norepinephrine (also known as noradrenaline)
• Acetylcholine (ACh)
• GABA (gamma aminobutyric acid)
• Glutamate
• Endorphins
• Dopamine
• Epinephrine (also known as adrenaline)
What are the major roles of each neurotransmitters? (see
handout)
image source: Gazzaniga, Heatherton, Halpern, Psychological Science (2011).
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How do Drugs Affect Neural Communication
Between Neurons?
Many drugs, especially those that affect moods or
behavior, work by interfering with normal functioning of
neurotransmitters in the synapse. How this occurs
depends on the drug, such as the following:
1. Drugs can mimic specific neurotransmitters.
• Nicotine is chemically similar to acetylcholine
and can occupy acetylcholine receptor sites,
stimulating skeletal muscles and causing the
heart to beat more rapidly.
2. Drugs can mimic or block the effects of a
neurotransmitter by fitting into receptor sites and
preventing the neurotransmitter from acting.
• The drug curare produces almost instant
paralysis by blocking acetylcholine receptor
sites on motor neurons.
3. Drugs can affect the length of time the
neurotransmitter remains in the synaptic gap, either
increasing or decreasing the amount available to the
postsynaptic receptor.
• Prozac prevents the reuptake of serotonin,
which increases the likelihood of synaptic
communication.
4. Drugs can increase or decrease the amount of
neurotransmitters released by neurons.
• MDMA increases the release of serotonin in
the brain.
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How Drugs Affect the Communication Process
Agonists
Antagonists
Drugs that enhance the actions
of neurotransmitters.
Drugs that inhibit the actions of
neurotransmitters.
image source: Gazzaniga, Heatherton, Halpern, Psychological Science (2013).
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Deficits and Surpluses of Neurotransmitters
(see handout)
Who has
• Alzheimer disease (deficit of acetylcholine (ACh) in
the hippocampus)?
• Parkinson’s disease (deficits of dopamine in the
substantia nigra)?
Alzheimers disease:
• Estimated 20 million worldwide suffer from Alzheimer,
4 million in the United States.
• It is hypothesized that high fat diets elevate the risk of
Alzheimers.
Learn more about these if you have a loved one suffering
from Alzheimer. Ignorance can help foster fear of
Alzheimer. Learning more can help you deal with the
stress of the disease.
Alzheimers: Time, July 17, 2000
Parkinson’s: Newsweek, May 22, 2000
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Who has / had Alzheimer’s Disease?
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Who has / had Parkinson’s Disease?