Scientific American Mind-June/July 2007

(The Authors)
Seeing Is Learning
Motion pictures, of the kind
shown in these sequences, can
expedite physical therapy. By
watching motions they have
lost—say, picking up a piece of
fruit—stroke patients activate
mirror neurons, enabling their
brains to relearn the movements
more readily.
Using functional magnetic resonance imaging
(fMRI), Rizzolatti and his colleagues soon
documented the same phenomenon in humans
and dubbed the responsible nerve cells “mirror
neurons” [see “A Revealing Refl ection,” by David
Dobbs; Scientifi c American Mind, April/
May 2006]. These cells look like any other neuron
but boast a surprising double function: they
become active during any type of directed behavior—chewing
food, throwing a ball, performing
a dance—whether we do it ourselves or simply
watch someone else do it. Indeed, our conscious
brain generates an inner simulation of
sorts when we follow the actions of another person.
Mirror neurons are presumed to be abundant
in brain regions responsible for planning
and initiating actions, including the primary motor
cortex, the premotor cortex and supplementary
motor areas.
Since Rizzolatti’s discovery, other scientists
have revealed that mirror neurons refl ect not
only the actions of other people but their intentions
and emotions as well. The discovery is offering
scientists new insight into, among other
things, human empathy, language evolution and
theories of mind. In addition, mirror neurons
FERDINAND BINKOFSKI is a neurologist and neuroscientist at the
University Medical Center of Schleswig-Holstein in Luebeck, Germany.
GIOVANNI BUCCINO is a researcher at the University of Parma in Italy.
may help explain certain neurological conditions.
For example, some evidence suggests that
autistic children may suffer from mirror neuron
defi ciencies, leaving them unable to intuit others’
emotional states. Our own work indicates that
the mirror system can be enlisted to expedite the
rehabilitation of hemorrhagic stroke patients.
Monkey See, Monkey Heal
In 2001 another research team at Parma, led
by one of us (Buccino), used fMRI to track brain
activity in people watching video sequences
showing mouth, hand or foot movements. As it
turned out, when the subjects watched a mouth
move, the part of their brain responsible for controlling
their mouth lit up. Likewise, observing
hand and foot images engaged the corresponding
brain regions. These responses remained below
the action threshold—the subjects did not actually
move—but they matched the brain responses
to video exactly. Given these fi ndings, we speculated
that patients who had suffered a cerebral
hemorrhage might regain lost movements more
readily if, as part of their therapy, they watched
others coordinate these actions.
During physical therapy, brain regions near
the site of damage do often take on lost functions,
but it is a gradual process. It seemed logical
that this transfer might happen faster if the neurons
in question could rehearse their new role. To
test the idea, we recruited stroke patients participating
in a 40-day rehabilitation program at
80 SCIENTIFIC AMERICAN MIND June/July 2007
COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.
FERDINAND BINKOFSKI AND GIOVANNI BUCCINO