You Inherit Those Convolutions On Your Brain.

Eight cranial bones form the skull,
scientists say, and variations in the shape
of these bones relate to our ancestral
background. A new study takes this past
research one step further. A team from
UC San Diego discovered the wrinkled
outer layer of the brain may owe an
equal amount to family inheritance.
Depending on personal lineage, cortical
patterns resulting from genetic ancestry
accounted for 47 to 66 percent of
variation among people in the new study,
the researchers say.
“Even in the modern contemporary
United States’ population, with its
melting pot of different cultures, it was
still possible to correlate brain cortex
structure to ancestral background,” Dr.
Chun Chieh Fan, a graduate student in
cognitive science, stated in a press
release .
We know that our brains are malleable,
so much so that our experiences and
what we learn and even our most
common daily thoughts influence the
strength of its synaptic connections and
the formation of networks. Our brains, it
would seem, are sculpted as naturally as
clay. Naturally, then, we would expect
our family — and the many encounters
and interactions such relationships
entail — have an impact on our brains.
However, does family influence go back
even further, even deeper? Does genetic
inheritance affect the outer layer of the
brain?
To answer these questions, researchers
led by Dr. Anders Dale, a professor of
radiology, neurosciences, psychiatry, and
cognitive science, dipped into data from
the Pediatric Imaging, Neurocognition,
and Genetics (PING) study. This 2009
project collected neuroimaging and
genotyping data from more than 1,200
children and teens at 10 locations in the
U.S. to create a research repository to be
used by scientists around the world.
The surface of the brain changes very
little after age 12, so the scientists of the
current study analyzed genetic and
neuroimaging information from a subset
of PING participants: 562 children, all
over the age of 12.
After examining each child’s genes to
determine her or his lineage, the
researchers next analyzed each child’s
neuroimaging scans. The science team
used a sophisticated software suite to
map the cerebral cortex. After comparing
the results to each child’s genetic data,
the scientists next evaluated the overall
data. What did they find?
Patterns Emerge
No relationship existed between brain
shape and cognitive abilities. However,
tiny differences in brain geometry
uncovered by the software did correlate
to genetics, specifically lineage.
Naturally, the genetics of all the children
ran along a continuum, with each child
representing, say, 40 percent of one
lineage and 60 percent of another.
Surprisingly, though, these percentages
linked to “subtle, but systematic”
differences, in Dale’s words, among
cortex shapes. In particular, regional
patterns of folding and gyrification — the
convolutions which give the brain its
wrinkled appearance — were the most
informative features, the tell-tale signs of
a child’s lineage.
Why is this important? One reason: an
understanding of these differences will
help scientists create appropriate
standards of comparison when deciding
what might be abnormal for a particular
individual. Knowing which differences in
brain topography are simply reflective of
ancestry, a doctor would be able to focus
instead on dissimilarities that might
account for an illness or disease
symptom.
Source: Fan CC, Bartxch H, Schork AJ, et
al. Modeling the 3D Geometry of the
Cortical Surface with Genetic Ancestry.
Current Biology. 2015.