An international team of researchers has found via study that a groove
in the brain, which they have named the ‘superior temporal asymmetrical pit’
(STAP) appears to be unique to humans as it is barely noticeable in primates. The
team suggests their finding may help better understand the evolution of our
species. Medical scientists and doctors have known about the STAP for some
time, but until now, it was not known just how unique it is. It is on average
just 4.5-centimetres long and is deeper in the right hemisphere than it is in
the left. No one knows why the groove exists, but its location offers clues—it
is likely associated with communication, the researchers note. To learn more
about the STAP, the researchers looked at brain scans of 177 people and 73
chimpanzees—analyses revealed that while clearly present in all the human
scans, it was barely present in any of chimps.
The team notes that in the right hemisphere, the groove is in a part of
the brain involved in facial recognition and in figuring out the motives or
feelings of other people. In the left hemisphere, the groove runs through a
part of the brain very clearly associated with language skills. The human brain
is approximately three times as big as a chimp's, yet finding functional
differences in brain structure has been difficult to pinpoint. One structure
that has been seen to be different is Broca's area, which is known to be
important to speech. It is smaller in chimps which would seem to make sense as
their speech capabilities are far less complex. The researchers note that the
STAP is prominent in people of all ages, from those still in the womb to the
elderly. That suggests, that the groove is involved in inherited traits—traits
not present in other primates.
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