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Handy feeling
13:32 06 November 2000
An
amputee given a double
hand
transplant has regained the feeling in his
"new" limbs within a few months, according to
researchers in France.
Their
finding shows that a brain that has reorganised itself to cope with a
missing limb can quickly readjust again when new limbs are attached.
Pascal
Giraux at the Institute of Cognitive Sciences in Bron and his
colleagues studied a gardener who lost both hands three centimetres
above the wrist in 1996. In January this year, the 37-year-old man
received two new transplanted hands from the same group in Lyons that
did the world''s first hand transplant in 1998.
The
researchers used functional magnetic imaging to scan the brain of the
man, known as CD. They took the first scan about half a year before the
transplant operation, and follow-up scans two, four and six months
afterwards. During each session, the man was asked to flex and extend
the elbows of both arms and the last four digits on each hand.
Brain invasion
In
the pre-operative scan, the researchers found that part of the brain
that controlled the elbow area had invaded another part that once
represented the hands.
Just
two months after the surgery, however, the right hand area had pretty
much reclaimed its old place. Within four months, both hands were
represented more or less normally, and sensation had begun to return.
"It''s a very fast process," says Giraux.
The
brain is known to be highly plastic. Blind people''s brains relinquish
parts of the visual cortex to touch. In amputees, brain areas once
dedicated to a foot devote themselves to the stump. But the speed with
which CD''s brain readjusted to cope with new limbs has surprised
researchers.
This
research was presented at a conference in New Orleans, organised by the
US-based Society for Neuroscience. New Scientist''s full coverage of the
conference is here: www.newscientist.com/conferences/