|newscientist.com, 10-9-2014. By Helen Thomson
Woman of 24 found to have no cerebellum in
DON’T mind the gap. A woman has reached the age of 24 without anyone
realising she was missing a large part of her brain. The case highlights just
how adaptable the organ is.
The discovery was made when the woman was
admitted to the Chinese PLA General Hospital of Jinan Military Area Command in
Shandong Province complaining of dizziness and nausea. She told doctors she’d
had problems walking steadily for most of her life, and her mother reported that
she hadn’t walked until she was 7 and that her speech only became intelligible
at the age of 6.
Doctors did a CAT scan and immediately identified the
source of the problem – her entire cerebellum was missing (see scan, above). The
space where it should be was empty of tissue. Instead it was filled with
cerebrospinal fluid, which cushions the brain and provides defence against
The cerebellum – sometimes known as the “little brain” – is
located underneath the two hemispheres. It looks different from the rest of the
brain because it consists of much smaller and more compact folds of tissue. It
represents about 10 per cent of the brain’s total volume but contains 50 per
cent of its neurons.
Although it is not unheard of to have part of your
brain missing, either congenitally or from surgery, the woman joins an elite
club of just nine people who are known to have lived without their entire
cerebellum. A detailed description of how the disorder affects a living adult is
almost non-existent, say doctors from the Chinese hospital, because most people
with the condition die at a young age and the problem is only discovered on
autopsy (Brain, doi.org/vh7).
The cerebellum’s main job is to control voluntary movements and balance, and
it is also thought to be involved in our ability to learn specific motor actions
and speak. Problems in the cerebellum can lead to severe mental impairment,
movement disorders, epilepsy or a potentially fatal build-up of fluid in the
brain. However, in this woman, the missing cerebellum resulted in only mild to
moderate motor deficiency, and mild speech problems such as slightly slurred
pronunciation. Her doctors describe these effects as “less than would be
expected”, and say her case highlights the remarkable plasticity of the brain.
“These rare cases are interesting to understand how the brain circuitry
works and compensates for missing parts,” says Mario Manto, who researches
cerebellar disorders at the Free University of Brussels in Belgium. The
patient’s doctors suggest that normal cerebellar function may have been taken
over by the cortex – brain scans should reveal the answer.
Scan of a person's brain showing a hole where the cerebellum should be
A hole at the back where the cerebellum should be
Feng Yu et al.
Two brain scans, one with a hole where the cerebellum should be
Comparison with a normal brain
Top image: Feng Yu et al.; Bottom image:
Zephyr/Science Photo Library
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