Download Why Migraines Strike - Fullfrontalanatomy.com

Why Migraines Strike
Current Issues in Biology, Volume 6
Scientific American
Lectures by Greg Podgorski, Utah State University
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• More than 300 million people worldwide suffer from
migraine
• Migraine costs the U.S. roughly $17 billion each year
in lost work, disability payments and health care
expenses
• New understanding of the neurobiology of migraine
give hope that effective treatment will be available soon
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• Migraine always involves severe headache and is
often accompanied by nausea and sensitivity to light
and sound
• About twice as many women as
men suffer migraine
• The frequency and duration of
migraine varies widely, with the
average being one or two day-long
attacks per month
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• There is a genetic influence in migraine, but the
genetics are complex with many genes working with the
environment to influence migraine susceptibility
• Migraine headache was long thought to be caused by
a constriction of brain blood vessels
• We now know that brain blood flow increases prior to
migraine and that this is unlikely to be the source of the
pain
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• About 30% of migraine sufferers experience
hallucinations known as aura before their headaches
begin
• A spreading wave of intense
neural activity in the brain’s cortex
followed by a prolonged inhibition
of the formerly excited cells occurs
during aura
• Though first discovered in patients with aura, this
cortical spreading depression probably underlies
migraine pain in all migraine sufferers
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• Migraine pain comes when trigeminal nerves are
activated and transmit pain signals from the membranes
that surround the brain
• The pain signals are sent to an area in the brain stem
called the trigeminal nucleus and eventually relayed to
the sensory cortex, which is involved in pain perception
• An open question is what first activates the trigeminal
nerve system in migraine
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• There are two schools of thought for how migraine
pain in triggered
• One view is that cortical
spreading depression
induces pain
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• Another view of migraine pain is that malfunctioning
neurons in the brain stem are the trigger
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• All current drugs to prevent migraine were developed
for other disorders and work only 50% of the time in
50% of patients
• All these drugs inhibit cortical spreading depression,
but only as a side-effect of their main action
• Drugs designed specifically to prevent cortical
spreading depression and the onset of migraine are
being developed
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• Drugs designed to treat rather than prevent migraine
also have problems
• Triptans work through their side-effect of blocking a
chemical signal between trigeminal neurons and the
trigeminal nucleus
• The main effect of triptans is the unwanted action of
constricting blood vessels throughout the body
• New drugs are being developed that specifically inhibit
the release of chemical signals sent from the trigeminal
neurons to the brain stem
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Concept Review
• Scientists and physicians are finally coming to see
migraine as a complex, potentially treatable disorder,
not an imaginary affliction
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Migraine affects more:
a) men than woman
b) woman than men
c) older adults than younger adults
d) younger adults than older adults
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Migraine affects more:
b) woman than men
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
It was incorrectly thought that migraine is due to:
a) decreased brain blood flow
b) increased brain blood flow
c) decreased activity of trigeminal neurons
d) swelling of the membranes that surround the brain
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
It was incorrectly thought that migraine is due to:
a) decreased brain blood flow
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Aura involves:
a) severe pain before migraine headache
b) severe pain after migraine headache
c) hallucinations before migraine headache
d) the headache of migraine
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Aura involves:
c) hallucinations before migraine headache
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Cortical spreading depression is:
a) the psychological depression experienced by many
migraine sufferers
b) a spreading wave of nerve activity depression in the
Raphe nucleus of the brain stem
c) a wave-like activation of the trigeminal neurons
d) a spreading wave of nerve stimulation followed by
nerve inactivity in the brain’s cortex
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Cortical spreading depression is:
d) a spreading wave of nerve stimulation followed by
nerve inactivity in the brain’s cortex
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
The pain of migraine is triggered when:
a) trigeminal neurons transmit pain signals from the
membranes surrounding the brain
b) cortical spreading depression reaches the pain
processing center of the cortex
c) increased blood flow causes the brain to swell
d) light or sound induce increased nerve stimulation in
hypersensitive individuals
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
The pain of migraine is triggered when:
a) trigeminal neurons transmit pain signals from the
membranes surrounding the brain
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Current generation drugs to treat or prevent the onset of
migraine:
a) were developed to prevent cortical spreading
depression
b) were developed to block specific chemical signals
between the brain stem and cortex
c) were developed to decrease the activity of trigeminal
neurons
d) work almost entirely through their side-effects
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
Current generation drugs to treat or prevent the onset of
migraine:
d) work almost entirely through their side-effects
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
A promising target for drugs to treat migraine pain is:
a) blocking the chemical signal sent from trigeminal
neurons to the brain stem
b) increasing the extent of cortical spreading depression
c) constricting blood vessels in the brain
d) suppressing nerve activity throughout the brain
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Testing Your Comprehension
A promising target for drugs to treat migraine pain is:
a) blocking the chemical signal sent from trigeminal
neurons to the brain stem
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Thinking About Science
If nerve clusters in the brain stem inhibit trigeminal
neurons from firing, what would be a promising approach
to preventing migraine pain?
a) develop drugs that increase the activity of brain stem
nerve clusters
b) develop drugs that decrease the activity of brain stem
nerve clusters
c) develop drugs that increase the activity of trigeminal
neurons
d) develop drugs that decrease the sensitivity of
trigeminal neurons to the signal from brain stem nerve
clusters
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Thinking About Science
If nerve clusters in the brain stem inhibit trigeminal
neurons from firing, what would be a promising approach
to preventing migraine pain?
a) develop drugs that increase the activity of brain stem
nerve clusters
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Biology and Society
If migraines affected more men than woman, migraine
research would be more advanced because migraine
would not have been viewed as an imaginary affliction
Strongly
Agree
A.
B.
C.
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
D.
E.
Strongly
Disagree
Why Migraines Strike
Interpreting Charts and Graphs
In this model, which of the
following would NOT be a
reasonable approach to
preventing migraine pain?
a) block cortical spreading
depression
b) increase the efficiency of
signaling between the
trigeminal neurons and brain
stem
c) decrease the output of the d) decrease the sensitivity of
signal from the brain stem to the thalamus to the signal
the thalamus
from the brain stem
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings
Why Migraines Strike
Interpreting Charts and Graphs
In this model, which of the
following would NOT be a
reasonable approach to
preventing migraine pain?
b) increase the efficiency of
signaling between the
trigeminal neurons and brain
stem
Copyright © 2010 Pearson Education, Inc. publishing as Benjamin Cummings