Home' Trinidad and Tobago Guardian : November 21st 2015 Contents A26
body & soul
Guardian www.guardian.co.tt Saturday, November 21, 2015
A study of 153 brain scans has linked a particular
furrow, near the front of each hemisphere, to hal-
lucinations in schizophrenia.
This fold tends to be shorter in those patients who
hallucinate, compared with those who do not.
It is an area of the brain that appears to have a role
in distinguishing real perceptions from imagined ones.
Researchers say the findings, published in Nature
Communications, might eventually help with early
The brain wrinkle, called the paracingulate sulcus
or PCS, varies considerably in shape between indi-
viduals. It is one of the final folds to develop, appearing
in the brain only just before birth.
"The brain develops throughout life, but aspects
such as whether the PCS is going to be a particularly
prominent fold---or not---may be apparent in the brain
at an early stage," said Jon Simons, a neuroscientist
at the University of Cambridge, UK.
"It might be that a reduction in this brain fold gives
somebody a predisposition towards developing some-
thing like hallucinations later on in life."
If further work shows that the difference can be
detected before the onset of symptoms, for example,
Dr Simons said it might be possible to offer extra sup-
port to people who face that elevated risk.
But he stressed that schizophrenia is a complicated
phenomenon. Hallucinations are one of the main
symptoms, but some patients are diagnosed on the
basis of other irregular thought processes.
"We ve known for some time that disorders like
schizophrenia are not down to a single region of the
brain. Changes are seen throughout various different
Dr Simons and his colleagues used data from the
Australian Schizophrenia Research Bank, including
structural MRI scans revealing the detailed physical
dimensions of 153 individual brains: 113 people with
schizophrenia and 40 healthy controls.
Because this database includes other important
information about the subjects, the team was able to
choose its samples very carefully.
The schizophrenia patients, for example, were split
into those with a history of hallucinations (79 people)
and those without (34)---but the two groups were
closely matched in other ways.
"We re selecting patients to put into each group
such that those two groups are... as directly comparable
as possible," Dr Simons told the BBC. Factors such as
the individuals age, sex, medication and even whether
they were left- or right-handed were all taken into
"So as close as we can get it, the only difference
between those two groups is that one group experiences
hallucinations and the other one doesn t."
In the brain scans, the team looked for differences
in the PCS because they knew from a previous study
that the length of this fold showed a correlation with
people s "reality monitoring" ability.
And sure enough, this was reflected in the patients
suffering hallucinations: on average, they had a PCS
that was about 2cm shorter than the patients without
hallucinations, and 3cm shorter than the healthy con-
Turning this measurement around, the team cal-
culated that a one centimetre decrease in the length
of the furrow corresponded to a 20 per cent increase
in the risk of experiencing hallucinations.
The study s first author, Jane Garrison, said that
although other factors were certainly at play when a
brain generates hallucinations, this was an important
"We think that the PCS is involved in brain networks
that help us recognise information that has been gen-
erated ourselves," she explained. "People with a shorter
PCS seem less able to distinguish the origin of such
information, and appear more likely to experience it
as having been generated externally.
"Hallucinations are very complex phenomena that
are a hallmark of mental illness and, in different
forms, are also quite common across the gen-
"There is likely to be more than one expla-
nation for why they arise, but this finding
seems to help explain why some people expe-
rience things that are not actually real."
Stephen Lawrie, a professor of psychiatry at
the University of Edinburgh, was not involved
with the research but has studied brain struc-
ture in relation to schizophrenia and hallu-
He said the new findings were thoroughly
researched and quite surprising---partly
because, although schizophrenia is known to
affect frontal parts of the brain
like the PCS, hallucinations
in particular are often asso-
ciated with other areas that
control perception and lan-
guage. "There s quite a
strong literature showing
that auditory hallucinations
are related to dysfunction or
structural disruption in language
areas of the brain," Prof Lawrie told BBC
YOUR DAILY HEALTH
News and Advice
Brain wrinkle linked to hallucinations
The size of some of your brain wrinkles may
influence whether you have schizophrenic hallucinations.
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