[nfbwatlk] Fwd: [Wcb-l] Old brain, new tricks

[Alco Canfield]

ALCO

Begin forwarded message:

> From: "Carl Jarvis" <carjar82 at gmail.com>
> Date: September 6, 2010 8:20:45 AM PDT
> To: "wcb" <Wcb-l at wcbinfo.org>
> Subject: [Wcb-l] Old brain, new tricks
> 

> Old brain, new tricks
> 
> New research on the blind is revealing the brain's ability to adapt--- and
> may lead to new therapies for everything from strokes to chronic pain
> 
> By Cara Feinberg
> 
> The Boston Globe, January 15, 2006
> 
> ESREF ARMAGAN is a 52-year-old Turkish painter who has been blind in both
> eyes since the day he was born. He has never seen a coffee cup, a
> toothbrush, an elephant, or a tree-lined street, but he can draw them each,
> from any perspective, with or without shadows depending on the time of day.
> His portrait of President Clinton, which he painted from an embossed
> photograph, looks, well, like Clinton-complete with grey hair and bulbous
> nose-and though Armagan has never had an art lesson, the streets he paints
> stretch into the distance as converging parallel lines.
> 
> 
> 
> For years, Armagan has been a phenomenon in the art world, displaying his
> work in museums around the globe. But it was not until two summers ago, when
> he traveled to Boston, that scientists were able to study precisely how he
> generates such images. Their hope was that he might teach them something
> about neural "plasticity"--the brain's ability to reorganize its functions
> based on new information and experiences. If Armagan had never seen with his
> eyes, how had his brain adapted to give him visual representations of the
> world, and more importantly, what could it reveal about brain adaptation in
> general?
> 
> 
> 
> In July of 2004, at the Center for Noninvasive Brain Stimulation at Beth
> Israel Deaconess Hospital in Boston, Armagan agreed to have his brain imaged
> in a magnetic resonance imaging (MRI) machine while he drew with a pencil on
> a sheet of paper. He explored a set of objects by touch-a coffee cup, a toy
> elephant, a toothbrush-and then was told to imagine them and draw them all
> from memory. Each time, his drawings hit the mark. "What we saw in the scan
> was quite amazing," says Dr. Alvaro Pascual-Leone, an associate professor of
> neurology at Harvard Medical School and director of the center. He and two
> colleagues in Beth Israel Deaconess's neurology department, Amir Amedi, PhD,
> and Dr. Lotfi Merabet, conducted a series of scans, each time challenging
> Armagan with more complex tasks. "Esref's visual cortex lit up during the
> drawing tasks as if he were actually seeing," says Pascual-Leone. "His scan,
> to the untrained eye, might look like the brain of a sighted person."
> Armagan presented a unique learning opportunity for the scientists at Beth
> Israel Deaconess. Pascual-Leone and his colleagues had access to a blind
> person able to render-pictorially-what his mind's eye had captured. But more
> importantly, they now had the technology to look at his brain while he
> rendered it, and to glimpse how his visual cortex functioned after 52 years
> without vision.
> 
> 
> 
> For centuries, scientists held that the brain was a fixed entity, that it
> was hard-wired for each individual function, and incapable of reorganizing
> after injury. In the late 1850s, the French neurosurgeon Paul Broca was the
> first to argue that language was associated with a specific part of the
> brain, and other investigators soon followed suit:
> 
> 
> 
> The visual cortex at the back of the brain, they hypothesized, processed
> only vision, the somatosensory cortex in the mid-brain processed only pain,
> vibration, and touch, the auditory cortex on the sides of the brain existed
> solely to process sound.
> 
> 
> 
> In the last half-century, however, new technology and cutting-edge
> experiments like those of Pascual-Leone and his colleagues, have exploded
> that dogma, revealing not only that the brain does in fact reorganize and
> adapt, it does so all the time. "What we saw in Esref," Pascual-Leone
> explains, "was that he was using his visual cortex. It wasn't lying dormant.
> It hadn't shrunk or disappeared. Instead, it was recruited by other senses."
> The brain, as work like Pascual-Leone's is revealing, is a lot more
> resourceful than we ever knew it was.
> 
> 
> 
> Dr. Pascual-Leone has been studying the brain for three decades, examining
> its capacity to establish new neural connections, how to use the connections
> that exist, and how to harness them to create better rehabilitation
> strategies after trauma or sickness. Pascual-Leone's patients and study
> subjects range from normal-functioning adults with special gifts like
> Armagan, to those with a range of neurological deficits, from sensory loss,
> to strokes, to chronic pain, to medically-resistant depression.
> 
> 
> 
> The blind, Pascual-Leone explains, provide an excellent opportunity to study
> brain plasticity. "A large part of our brains is devoted to vision-some
> estimate more than half," he says. "The question we are asking is what
> happens to that part of the brain when there is no input from the eyes?"
> Over the past 10 years, Pascual-Leone and several other scientists,
> including his colleague Amir Amedi, have conducted experiments examining the
> brain's role in sensory perception, and much of their work has been with
> blind subjects. Using neural scans and transcranial magnetic stimulation
> (TMS)-a technique in which a noninvasive handheld device is used to
> stimulate or temporarily interfere with targeted brain functions-several
> studies have found activation in blind subjects' visual cortices, despite
> the fact they cannot see.
> 
> 
> 
> In an early study Pascual-Leone coauthored with Dr. Leonardo Cohen at the
> National Institutes of Health, results showed that during Braille-reading
> tasks, blind subjects' visual cortices lit up like lamps. But the mere fact
> that there was activity in that section, he pointed out, did not necessarily
> prove it was vital to that function. That, he said, is where TMS comes in.
> "If you use TMS to temporarily interfere with the visual cortex during
> certain tactile tasks, like reading Braille, you'll find that early-blind
> subjects suddenly have trouble performing them," says Amedi, whose own
> independent studies have revealed similar results during language-based
> tasks. In the blind, unlike the sighted, the TMS interference, researchers
> believe, shows that the visual cortex is engaged-and in fact required-for
> certain nonvisual tasks.
> 
> 
> 
> So if, as scientists' findings suggest, the visual cortex need not be
> devoted solely to sight, how does the brain adapt after injury or new
> environmental influences? Does the brain forge new connections that did not
> exist before, or are the connections already there lying dormant, pressed
> into service by the circumstances?
> 
> 
> 
> Pascual-Leone's current work with his colleagues at Beth Israel Deaconess
> aims to answer those questions. For the past few years, they have been
> studying sighted subjects who volunteer to be blindfolded for five days and
> learn certain nonvisual tasks, including rudimentary Braille. In every case,
> before subjects donned the blindfold,functional MRI (fMRI) scans revealed
> little activity in their visual cortices during tactile tasks. After the
> subjects wore the blindfolds for two days, however, the scans showed bright
> patches of activity in the visual brain when the subjects used their fingers
> for tactile or Braille-reading tasks. By day five, the visual cortex glowed
> steadily during these same tasks. Yet two hours after the blindfolds were
> removed and the subjects' eyes had readjusted, scans of the visual area of
> their brains were as dark as they'd been on day one. Once the blindfolds
> were removed, touching, handling objects, and Braille-reading no longer
> activated "sight" in the seeing.
> 
> 
> 
> The cortical adaptations that occur in the blindfold studies appear-and
> disappear-too quickly for any new nerve connections to grow, Pascual-Leone
> believes. He compares the adaptive pathways in the brain to detours after
> road blocks; building a new street takes a long time, he explains, but if
> there are other existing surrounding roads, they can be used right away.
> These immediate neurological detours reveal the brain's capacity to adapt in
> response to environmental factors, but it is sustained sight loss that will
> more likely result in lasting adaptations, he says.
> 
> 
> 
> Over time, if the brain continues to follow the detour routes, he believes,
> it starts to modify them to make them better, and might even make new
> structural connections. The fact that change occurred so immediately in the
> blindfolded subjects, he says, indicates that the visual cortex may
> inherently possess the machinery necessary to process nonvisual information.
> 
> 
> 
> Pascual-Leone and his colleagues believe that humans work with a reserve of
> existing connections dictated by their  specific genetic make-up that,
> depending on their use, will become masked or unmasked by the individual's
> circumstances. "What Esref and the blindfold studies show us," he says, is
> that lacking sight, the brain draws on information from the other senses.
> "Even in the absence of vision," he says, "the visual cortex is involved in
> creating images." In other words, the work of Pascual-Leone and others
> suggests that the brain has many additional capacities it can call on in a
> pinch.
> 
> 
> 
> As both a physician and a researcher, Pascual-Leone aims to put his findings
> from his studies of the blind to use in developing rehabilitative therapies
> for other types of conditions. But his lab is not alone in its development
> of new treatments.
> 
> 
> 
> Other breakthrough therapies have arisen for strokes, autism, schizophrenia,
> spinal cord injuries, epilepsy, chronic pain, and many other previously
> "untreatable" conditions. At the University of California, San Francisco,
> one neuroscientist has developed a computer program to teach language skills
> to dyslexic children through what is called, "neural retraining." A
> professor in the department of psychology at the University of Alabama has
> used these developments to help stroke victims restore movement in their
> limbs. Two scientists at the University of Rochester have found that playing
> action video games can enhance a range of visual attention skills.
> 
> 
> 
> Yet despite the dozens of medical therapies that have been developed as a
> result of breakthroughs in thinking about brain plasticity, says
> Pascual-Leone, in both our scientific understanding of these mechanisms, and
> our ability to apply them clinically, we are still at the starting gate.
> 
> 
> 
> For researchers studying the brain, the next steps lie in learning enough
> about plasticity to harness it for individual needs. Through their work with
> the blind, Pascual-Leone and his colleagues hope to learn more about how
> visual images can be processed nonvisually in the brain-both for what it
> will tell them generally about how the brain works, and how, specifically,
> they might help the brain to work better for the newly blind or those who
> regain sight. Subjects like Esref Armagan, says Pascual-Leone, help
> jump-start that process. "We can never know what types of images were
> actually being created in Armagan's brain," he says. "But we know now that
> when he draws those images, we can understand them visually without a
> doubt."  This makes it seem as if he is seeing, says Pascual-Leone. "And
> when we looked at his brain, we could see how."
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