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Subject: IMAGING STUDY SHOWS BRAIN MATURING
U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH
NIH News
National Institute of Mental Health
http://www.nimh.nih.gov/
EMBARGOED FOR RELEASE
Monday, May 17, 2004
5:00 p.m. ET
CONTACT:
Jules Asher
NIMH Press Office
301-443-4536
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IMAGING STUDY SHOWS BRAIN MATURING
The brain's center of reasoning and problem solving is
among the last to mature, a new study graphically reveals.
The decade-long magnetic resonance imaging (MRI) study of
normal brain development, from ages 4 to 21, by researchers
at NIH's National Institute of Mental Health (NIMH) and
University of California Los Angeles (UCLA) shows that such
"higher-order" brain centers, such as the prefrontal
cortex, don't fully develop until young adulthood.
A time-lapse 3-D movie that compresses 15 years of human
brain maturation, ages 5 to 20, into seconds shows gray
matter -- the working tissue of the brain's cortex --
diminishing in a back-to-front wave, likely reflecting the
pruning of unused neuronal connections during the teen
years. Cortex areas can be seen maturing at ages in which
relevant cognitive and functional developmental milestones
occur. The sequence of maturation also roughly parallels
the evolution of the mammalian brain, suggest Drs. Nitin
Gogtay, Judith Rapoport, NIMH, and Paul Thompson, Arthur
Toga, UCLA, and colleagues, whose study is published online
during the week of May 17, 2004 in "The Proceedings of the
National Academy of Sciences".
"To interpret brain changes we were seeing in
neurodevelopmental disorders like "schizophrenia"
(http://www.nimh.nih.gov/healthinformation/schizophreniamen
u.cfm), we needed a better picture of how the brain
normally develops," explained Rapoport.
The researchers scanned the same 13 healthy children and
teens every two years as they grew up, for 10 years. After
co-registering the scans with each other, using an
intricate set brain anatomical landmarks, they visualized
the ebb and flow of gray matter -- neurons and their
branch-like extensions -- in maps that, together, form the
movie showing brain maturation from ages 5 to 20.
It was long believed that a spurt of overproduction of gray
matter during the first 18 months of life was followed by a
steady decline as unused circuitry is discarded. Then, in
the late l990s, NIMH's Dr. Jay Giedd, a co-author of the
current study, and colleagues, discovered a "second wave of
overproduction of gray matter"
(http://www.nimh.nih.gov/publicat/teenbrain.cfm) just prior
to puberty, followed by a second bout of "use-it-or-lose-
it" pruning during the teen years.
The new study found that the first areas to mature (e.g.,
extreme front and back of the brain) are those with the
most basic functions, such as processing the senses and
movement. Areas involved in spatial orientation and
language (parietal lobes) follow. Areas with more advanced
functions -- integrating information from the senses,
reasoning and other "executive" functions (prefrontal
cortex) -- mature last.
In a related study published a few years ago, Rapoport and
colleagues discovered "an exaggerated wave of gray matter
loss"
(http://www.nimh.nih.gov/press/nimhprschizteens01.pdf) in
teens with "early onset schizophrenia"
(http://www.nimh.nih.gov/publicat/schizkids.cfm). These
teens, who became psychotic prior to puberty, lost four
times the normal amount of gray matter in their frontal
lobes, suggesting that childhood onset schizophrenia "may
be an exaggeration of a normal maturation process, perhaps
related to excessive synaptic pruning," note the
researchers. By contrast, children with autism show an
abnormal back-to-front wave of gray matter increases,
rather than decreases, suggesting "a specific faulty step
in early development."
Also participating in the new study were: Leslie Lusk,
Cathy Vaituzis, Tom Nugent, David Herman, Drs. Deanna
Greenstein, Liv Clasen, NIMH; Kiralee Hayashi, UCLA.
The graphic "Time-Lapse Imaging Tracks Brain Maturation
from ages 5 to 20" is available at
http://www.nimh.nih.gov/press/prbrainmaturing.cfm#timelapse
.
A Time-lapse Imaging movie is available at
http://www.nimh.nih.gov/press/prbrainmaturing.mpeg.
NIMH is part of the National Institutes of Health (NIH),
the Federal Government's primary agency for biomedical and
behavioral research. NIH is a component of the U.S.
Department of Health and Human Services.
##
This NIH News Release is available online at:
http://www.nih.gov/news/pr/may2004/nimh-17.htm
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