observing traces of actual thought processes,
we're learning that the brain is much more complicated
than any computer we've ever encountered, even those designed
to perform many tasks at the same time.
a level on which the brain must have algorithms to figure
things out, like computers do," says Gabrieli. "And
it must have input and output. But the brain is capable
of massive parallel processing on a very high level. Some
computers can do that, but not nearly on the same scale
as the brain does." And the computer analogy, while
useful, ultimately breaks down: almost every brain cell
is its own processor, yet no cell can operate independently
as a computer chip can, relying instead on neural networks.
To an engineer, this may seem like an odd design, but
there can be no question that the brain gets the job done
mapping out functions within the brain and finding out
how they overlap, we may begin to understand what mechanisms
it uses to break apart tasks. We start to see how our
brain transforms us from a metabolic, mobile "machine"
into a person, complete with consciousness, creativity,
and the ability to learn.
kind of technology could also help us diagnose mental
disorders and abnormalities, paving the way for better
medical treatments. Gabrieli's lab has shown that children
with attention-deficit/hyperactivity disorder (ADHD),
a condition in which people are physically restless, have
difficulty controlling their impulses, or have difficulty
paying attention, show different fMRI activation patterns
from children without the disorder. In one of the tests,
young boys were asked to press a button whenever any letter
appeared on the screen in front of them except the letter
X. ADHD kids had trouble suppressing the impulse to press
the button and didn't show increased activity in the regions
of the brain that help regulate how we pay attention.
Ritalin, the drug commonly prescribed for these children,
increased ADHD kids' performance in the test and increased
activation in those regions.
doesn't matter whether you're looking at a drug's effects
or a learning process. By looking at the 'before' and
'after' conditions, we can watch the brain adapt its organization
based on new functions," Hirsch says. She and her
colleagues are using fMRI to uncover imaging criteria
for what makes a good drug for the treatment of chronic
pain. By mapping the brains of patients experiencing pain
before and after the administration of various drugs,
they learn better what to aim for in the development of
new pain medication.
are also turning to fMRI to help remove previously inoperable
brain tumors. Since tumors can often push other structures
out of place in the brain, surgeons often will not risk
removal for fear of damaging a nearby motor or sensory
cortex because they don't know its new boundaries. Surgery
might create a worse problem than the risk presented by
by using fMRI, Hirsch's lab has vastly decreased that
risk. A patient can be scanned before surgery, mapping
every standard function to create an individually-tailored
image of the functional organization of that patient's
brain. "Neurosurgical planning gives the surgeon
a high-resolution roadmap so the operation can be tailored
to the individual tumor," she says. The technique
has facilitated the successful removal of tumors from
over two hundred people.
the next decade, as the images become sharper and the
black box more transparent, many more people will benefit.
Likewise, our understanding of what makes us more than
a collection of atoms will improve. Scientists are finally
analyzing the brain, not by taking it apart, but by watching
it at work.