Johns Hopkins researchers have found strong evidence
supporting the view that the sleeping
mind functions the same as the waking mind, a discovery
that could significantly alter basic
understanding of the normal and abnormal brain.
The evidence comes from a study, appearing online in
October in the journal Human Brain
Mapping, of 11 healthy male and female participants
whose rapid eye movements in "dream" sleep were
timed using a video camera. The REM tracking was
accompanied by special MRI images designed to
visualize brain activity. Results revealed activity in
areas of the brain that control sight, hearing,
smell, touch, balance and body movements.
"This is the first time we have been able to detect
brain activity associated with REM in areas
that control senses other than sight," said lead researcher
Charles Hong, assistant professor in the
Department of Psychiatry and Behavioral Sciences at the
School of Medicine. "After comparing our
data to other studies on awake people, we learned that our
findings lend great support to the view
that the waking brain functions in a similar way."
Hong said this method might allow simultaneous
examination of major brain systems that are
activated when REM occur and are reported to be abnormal in
some psychiatric diseases.
In addition, Hong said, the researchers' method may be
useful in people with Alzheimer's
disease or schizophrenia, and even in infants. In awake
studies, subjects must follow instructions and
perform tasks to stimulate brain activity, tasks that these
groups might have difficulty completing.
The method also may be useful in people with movement
disorders such as Parkinson's disease.
"Head movements can create false data in MRI studies,"
Hong said, "while conveniently, REM
sleep greatly reduces muscle tone, thus head movements."
Finally, Hong said that obtaining reliable results
from awake participants would require studying
multiple subjects.
"In contrast, only six minutes of MRI data from a
single participant in our REM study produced
robust results," Hong said.
He added that the ability to draw results from a
single person permits researchers to compare
results with other data that are specific to an
individual.
"We can also analyze changes over time within a single
person with a psychiatric disease. Our
method may make a powerful tool to study the development of
the brain starting from birth," he said.
Other researchers from the Johns Hopkins
School of Medicine involved in the study
are James C. Harris, Godfrey D. Pearlson,
Jin-Suh Kim and Vince D. Calhoun, of the
Department of Psychiatry and Behavioral
Sciences; Xavier Golay, Joseph S. Gillen,
Peter C.M. van Zijl and James J. Pekar, of the
Department of Radiology and also the F.M.
Kirby Research Center for Functional Brain
Imaging, Kennedy Krieger Institute; Daniel
J. Simmonds, of the Department of Developmental
Cognitive Neurology; and David S. Zee, of the
Department of Neurology. James H. Fallon of the
University of California, Irvine also
contributed to this study.
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