Harvard: Changes in Brain's Anterior Cerebral Artery Could Cause Brain
April 24, 2012
Findings may eventually lead to new treatments for other types of
freeze' is a nearly universal experience—almost everyone has felt the
near-instantaneous headache brought on by a bite of ice cream or slurp
of ice-cold soda on the upper palate. However, scientists are still at a
loss to explain this phenomenon. Since migraine sufferers are more
likely to experience brain freeze than people who don't have this
often-debilitating condition, brain freeze may share a common mechanism
with other types of headaches, including those brought on by the trauma
of blast-related combat injuries in soldiers. One possible link between
brain freeze and other headache types is local changes in brain blood
In a new study, Melissa Mary Blatt, Michael Falvo, and Jessica Jasien of
the Department of Veterans Affairs New Jersey Health Care System, Brian
Deegan and Gearold O Laighin of the National University of Ireland
Galway, and Jorge Serrador of Harvard Medical School and the War Related
Illness and Injury Study Center of the Veterans Affairs New Jersey
Health Care System use brain freeze as a proxy for other types of
headaches. By bringing on brain freeze in the lab in volunteers and
studying blood flow in their brains, the researchers show that the
sudden headache seems to be triggered by an abrupt increase in blood
flow in the anterior cerebral artery and disappears when this artery
constricts. The findings could eventually lead to new treatments for a
variety of different headache types.
An abstract of their study entitled, "Cerebral Vascular Blood Flow
Changes During 'Brain Freeze,'" will be discussed at the meeting
Experimental Biology 2012 being held April 21-25 at the San Diego
Convention Center. The abstract is sponsored by the American
Physiological Society (APS), one of six scientific societies sponsoring
the conference, which last year attracted some 14,000 attendees.
Bringing on Brain Freeze
According to study leader Serrador, previous studies meant to assess
what physiological changes might prompt headaches have mainly relied on
various drugs, or brought in patients already in the throes of a
migraine to the lab. However, both methods have their limitations.
Pharmacological agents can induce other effects that can make research
results misleading, he says, and since researchers can't wait for
migraine sufferers to experience a migraine in the lab, those studies
miss the crucial period of headache formation that occurs sometimes
hours before scientists were able to study these patients.
To induce headache inside the lab and study it from start to finish,
Serrador explains, brain freeze is a perfect fit. It's easy to bring on
and resolves quickly without expensive or complicated equipment or
In this study, Serrador and his colleague recruited 13 healthy adults.
The researchers monitored the volunteers' blood flow in several brain
arteries using transcranial Doppler while they first sipped ice water
with the straw pressed against their upper palate—ideal conditions for
bringing on brain freeze—and then while sipping the same amount of water
at room temperature. The volunteers raised their hand once they felt the
pain of a brain freeze, then raised it again once the pain dissipated.
Findings showed that one particular artery, called the anterior cerebral
artery, dilated rapidly and flooded the brain with blood in conjunction
to when the volunteers felt pain. Soon after this dilation occurred, the
same vessel constricted as the volunteers' pain receded.
Changing the Course of Headaches
and his colleagues speculate that the dilation, then quick constriction,
may be a type of self-defense for the brain. "The brain is one of the
relatively important organs in the body, and it needs to be working all
the time," he explains. "It's fairly sensitive to temperature, so
vasodilation might be moving warm blood inside tissue to make sure the
brain stays warm." But because the skull is a closed structure, Serrador
adds, the sudden influx of blood could raise pressure and induce pain.
The following vasoconstriction may be a way to bring pressure down in
the brain before it reaches dangerous levels.
He notes that similar alterations in blood flow could be at work in
migraines, posttraumatic headaches, and other headache types. If further
research confirms these suspicions, then finding ways to control blood
flow could offer new treatments for these conditions. Drugs that block
sudden vasodilation or target channels involved specifically in the
vasodilation of headaches could be one way of changing headaches'