Dispatches from a rapidly changing, rapidly improving
It’s tax day here in the good old US of A: as good a time as any to remember
that, whether your take is that it’s happening because of massive government
spending or in spite of massive government spending, life in this country
— and pretty much everywhere else — is improving.
A 64-year-old woman has reported to doctors at Geneva University Hospital
the presence of a pale, milky-white and translucent third arm.
After examining the case, the woman’s neurologist, Asaid Khateb of the hospital’s
experimental neurophysiology laboratory, called the rare phenomenon credible.
The arm appeared to the woman a few days after suffering a stroke, doctors
But this case of what is known as a supernumerary phantom limb (SPL) is a
The upshot is that the woman can use the apparitional extremity to relieve
very real itches on the cheek. It cannot penetrate solid objects.
Khateb and his colleagues examined the patient’s brain using functional magnetic
resonance imaging (fMRI), a tool that allows doctors to see whether the brain
is truly stimulated, and to pinpoint where. In this case, the investigations
revealed that the woman actually experienced what she described.
Researchers instructed the woman to move her right hand. As expected, the
motor cortex and visual processing areas in the left side of her brain became
The same effects were observed to a lesser extent when the woman simply imagined
moving her right hand. Imaginary movements of the woman’s paralysed left hand
prompted the same activity in the brain, but on the right side.
But when doctors asked her to move her phantom arm, her brain reacted as
though the arm really existed and could be moved. In addition, the patient’s
visual cortex was also activated, indicating the she actually saw the imaginary
And when she was instructed to scratch her cheek, regions of the brain relating
to touch were activated
The Good News
Yes, this item is Better All the Time, not Astounding Science Facts (or Tales
of the Paranormal.)
Here’s why: it is extremely significant that the doctors treating this woman
were able to use an MRI to take a peek at what’s happening inside her brain
and confirm that it is sending signals that mean move the arm and receiving
signals that mean the hand is feeling something. Mapping brain activity
to physiological phenomena is one of the biggest breakthroughs of the past few
decades, and its promise is already being realized in a number of different
prevention and treatment options.
Consider this: earlier this week, my newborn
daughter was subjected to her first-ever hearing test. The pediatrician
hooked her up to an electroencephalograph, put headphones on her, and started
piping in sounds. In a matter of minutes, the brainwave scan confirmed that
she is hearing everything she should be hearing in each ear. Great news for
new parents when there is no problem, and extremely useful in the unfortunate
cases where there is a problem. Rather than waiting months or years for
a child’s behavior to reveal that something is amiss, these parents know what
they are up against from the very beginning.
Mapping the motions and sensations of a real limb to brain activity makes
it possible to treat paralysis by overriding existing damaged nerve connections
in order to return mobility to a paralyzed limb. Such mapping is also crucial
to developing a direct interface between the brain and electronically controlled
prosthetic limbs when there is no possibility of reviving the lost function,
as in the case of amputation. These kinds of treatments are already
But that’s just the beginning. Understanding how a phantom limb is represented
within the brain gives us a glimpse of how one day — probably not that far
in the future — we will be able to have very real experiences in virtual worlds.
The woman described is experiencing something that seems perfectly real to her,
as real as the actual experience of her actual arms. Essentially, her brain
has written and is executing a "program" for a virtual arm. Seeing
as this came about as the result of a stroke, and the woman probably wasn’t
looking for an extra limb, we tend to view this new bit of mental software as
a bug. But that bit of spontaneous buggy "software code" embeds some
powerful capabilities. That her doctors are able to watch it in action is a
very good sign. In time, it’s reasonable to expect that someone will figure
out how to reverse engineer this program, and begin to improve on it.
Live to see it!