“ Not only are the receptors organized in patches, but the axis that best describes their organization is pleasantness. ” — noam sobel, page 14
In the News
brain’s genetic
activity traced
over life span
Dramatic changes from just
after conception to old age
STORY ONE
by laura sanders
BRAIN: JSTAN/SHUT TERSTOCK; BAB Y: GRAFISSIMO/ISTOCKPHOTO; YOUNG GIRL: JOHNNYGREIG/ISTOCKPHOTO;
MIDDLE-AGED WOMAN: LAFLOR/ISTOCKPHOTO; OLDER WOMAN: YURI ARCURS/SHUTTERSTOCK
Human brains all work pretty much the same, using roughly the same genes in the same way to build and maintain the infrastructure that makes people who they
are, two new studies show. By charting
the brain’s genetic activity from before
birth to old age, the studies also reveal
that the brain continually remodels
itself throughout life.
In addition to uncovering details of
how the brain grows and ages, the results
may help scientists better understand
what goes awry in brain disorders such
as schizophrenia and autism.
“The complexity is mind-numbing,”
says neuroscientist Stephen Ginsberg of
the Nathan Kline Institute and Ne w York
University Langone Medical Center,
who wasn’t involved in the studies. “It
puts the brain in rarefied air.”
In the work, published in the Oct. 27
Nature, researchers focused not on
DNA — virtually every cell’s raw genetic
material is identical—but on when,
where and for how long each gene in the
DNA is turned on over the course of a
person’s life. To do this, the researchers
measured levels of mRNA, a molecule
whose appearance marks one of the first
steps in executing the orders contained
brain biochemistry changes dramatically with age as different sets of genes are
activated. Yet two new studies find remarkable consistency among individuals.
in a gene, in postmortem samples of
donated brains that ranged in age from
weeks after conception to old age.
Different patterns of mRNA levels
distinguish the brain from a heart, for
instance, and a human from a mouse,
too, says Nenad Šestan of Yale University
School of Medicine and coauthor of one
of the studies. “Essentially, we carry the
same genes as mice,” he says. “However,
in us, these genes are up to something
quite different.”
To see what human genes are up to in
the brain, Šestan’s team examined mRNA
levels of different genes in 57 brains. The
researchers divided the brain tissue up
by region, so they were also able to get an
idea of genes’ behavior in different parts
of the brain. A parallel study, headed by
Joel Kleinman of the National Insti-
tute of Mental Health in Bethesda, Md.,
studied 269 brains that also spanned the
lifetime to look for gene behavior in a
single region called the prefrontal cortex.
