OHSU Researchers Reveal the Science of Shivering
Researchers at Oregon Health & Science University’s
Neurological Sciences Institute have uncovered the
system that tells the body when to perform one of its
most basic defenses against the cold: shivering. The
scientists have discovered the brain’s wiring system,
which takes temperature information from the skin and
determines when a person should start shivering. Their
findings are published in the advance online edition
of the journal Nature Neuroscience.
“Shivering, which is actually heat production in
skeletal muscles, requires quite a bit of energy and
is usually the last strategy the body uses to maintain
its internal temperature to survive in a severe cold
environment. Other strategies to defend against the
cold, such as reducing heat loss to the environment by
restricting blood flow to the skin, also appear to be
controlled by the sensory mechanism that we found,”
explained Kazuhiro Nakamura, Ph.D., an OHSU Fellow for
Research Abroad from the Japan Society for the
Promotion of Science. He published the research along
with his colleague Shaun Morrison, Ph.D., a senior
scientist.
“One fascinating aspect of this study is that it shows
the sensory pathway for shivering, which can be
thought of as brain wiring, is parallel to but not the
same as the sensory pathway for conscious cold
detection. In other words, your body is both
consciously and subconsciously detecting the cold at
the same time using two different but related sensory
systems.”
The research was conducted by studying rats. It is
believed that the information directly applies to
humans because previous research has demonstrated many
parallels between the two species regarding this basic
function of sensing and regulating heat. While
studying these rats, the researchers were able to
trace the shivering sensory pathway from the skin to
specialized cells in a portion of the brain called the
lateral parabrachial nucleus. These cells can then
transmit information to another part of the brain
called the preoptic area, which decides when the body
should start shivering.
Shivering is one of the many automatic and
subconscious regulatory body functions, often called
homeostatic functions that the brain regulates. Other
examples include the adjustment of breathing rates,
blood pressure, heart rate and weight regulation.
Throughout the day, all of these important functions
take place in the body without conscious thought.
Without these important functions, humans and other
animals could not survive.
“This research is a fundamental science discovery that
furthers our knowledge about one of the many functions
that our brains are constantly monitoring, responding
to and adjusting to keep us alive and healthy,”
explained Morrison. “It is noteworthy, however, that
there are conditions, such as hypothermia and
hyperthermia, in which thermal sensory pathways come
into play and knowledge of the brain’s wiring can
provide important clues to locating dysfunction in
patients with abnormal thermal sensation. In addition,
our ability to sense and respond to temperature
changes degrades as we age.”
Source:-Oregon
Health & Science University
Published on the 4th January 2008
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