How The Brain Rewires Itself
Friday, Jan. 19, 2007
By SHARON BEGLEY
It wasa fairly modest experiment, as these things go, with volunteers trooping intothe lab at Harvard Medical School to learn and practice a little five-fingerpiano exercise. Neuroscientist Alvaro Pascual-Leone instructed the members ofone group to play as fluidly as they could, trying to keep to the metronome's 60beats per minute. Every day for five days, the volunteers practiced for twohours. Then they took a test.At the end of each day's practice session, theysat beneath a coil of wire that sent a brief magnetic pulse into the motorcortex of their brain, located in a strip running from the crown of the headtoward each ear. The so-called transcranial-magnetic-stimulation (TMS) testallows scientists to infer the function of neurons just beneath the coil. In thepiano players, the TMS mapped how much of the motor cortex controlled the fingermovements needed for the piano exercise. What the scientists found was thatafter a week of practice, the stretch of motor cortex devoted to these fingermovements took over surrounding areas like dandelions on a suburban lawn.Thefinding was in line with a growing number of discoveries at the time showingthat greater use of a particular muscle causes the brain to devote more corticalreal estate to it. But Pascual-Leone did not stop there. He extended theexperiment by having another group of volunteers merely think about practicingthe piano exercise. They played the simple piece of music in their head, holdingtheir hands still while imagining how they would move their fingers. Then theytoo sat beneath the TMS coil.When the scientists compared the TMS data on thetwo groups--those who actually tickled the ivories and those who only imagineddoing so--they glimpsed a revolutionary idea about the brain: the ability ofmere thought to alter the physical structure and function of our gray matter.For what the TMS revealed was that the region of motor cortex that controls thepiano-playing fingers also expanded in the brains of volunteers who imaginedplaying the music--just as it had in those who actually played it."Mentalpractice resulted in a similar reorganization" of the brain, Pascual-Leone laterwrote. If his results hold for other forms of movement (and there is no reasonto think they don't), then mentally practicing a golf swing or a forward pass ora swimming turn could lead to mastery with less physical practice. Even moreprofound, the discovery showed that mental training had the power to change thephysical structure of the brain.OVERTHROWING THE DOGMAFOR DECADES, THEPREVAILING DOGMA IN neuroscience was that the adult human brain is essentiallyimmutable, hardwired, fixed in form and function, so that by the time we reachadulthood we are pretty much stuck with what we have. Yes, it can create (andlose) synapses, the connections between neurons that encode memories andlearning. And it can suffer injury and degeneration. But this view held that ifgenes and development dictate that one cluster of neurons will process signalsfrom the eye and another cluster will move the fingers of the right hand, thenthey'll do that and nothing else until the day you die. There was good reasonfor lavishly illustrated brain books to show the function, size and location ofthe brain's structures in permanent ink.The doctrine of the unchanging human brain has had profound ramifications. Forone thing, it lowered expectations about the value of rehabilitation for adultswho had suffered brain damage from a stroke or about the possibility of fixingthe pathological wiring that underlies psychiatric diseases. And it implied thatother brain-based fixities, such as the happiness set point that, according to agrowing body of research, a person returns to after the deepest tragedy or thegreatest joy, are nearly unalterable.There are uncharted worlds inside your head, but science is drawing a mapButresearch in the past few years has overthrown the dogma. In its place has comethe realization that the adult brain retains impressive powers of"neuroplasticity"--the ability to change its structure and function in responseto experience. These aren't minor tweaks either. Something as basic as thefunction of the visual or auditory cortex can change as a result of a person'sexperience of becoming deaf or blind at a young age. Even when the brain suffersa trauma late in life, it can rezone itself like a city in a frenzy of urbanrenewal. If a stroke knocks out, say, the neighborhood of motor cortex thatmoves the right arm, a new technique called constraint-induced movement therapycan coax next-door regions to take over the function of the damaged area. Thebrain can be rewired.The first discoveries of neuroplasticity came from studiesof how changes in the messages the brain receives through the senses can alterits structure and function. When no transmissions arrive from the eyes insomeone who has been blind from a young age, for instance, the visual cortex canlearn to hear or feel or even support verbal memory. When signals from the skinor muscles bombard the motor cortex or the somatosensory cortex (which processestouch), the brain expands the area that is wired to move, say, the fingers. Inthis sense, the very structure of our brain--the relative size of differentregions, the strength of connections between them, even theirfunctions--reflects the lives we have led. Like sand on a beach, the brain bearsthe footprints of the decisions we have made, the skills we have learned, theactions we have taken.SCRATCHING A PHANTOM LIMBAN EXTREME EXAMPLE OF HOWCHANGES IN the input reaching the brain can alter its structure is the silencethat falls over the somatosensory cortex after its owner has lost a limb. Soonafter a car crash took Victor Quintero's left arm from just above the elbow, hetold neuroscientist V.S. Ramachandran of the University of California at SanDiego that he could still feel the missing arm. Ramachandran decided toinvestigate. He had Victor sit still with his eyes closed and lightly brushedthe teenager's left cheek with a cotton swab.Time.comCNN.comSearch Archive Wednesday, February 28, 2007 HOME U.S. WORLD BLOGS BUSINESS & TECH HEALTH & SCIENCE ENTERTAINMENT PHOTOS MAGAZINE SPECIALS How The Brain Rewires ItselfFriday, Jan. 19, 2007 By SHARON BEGLEY Enlarge PhotoIllustration for TIME by David PlunkertArticle ToolsPrintEmailReprints (3 of 5)Where do you feel that? Ramachandran asked. On hisleft cheek, Victor answered--and the back of his missing hand. Ramachandranstroked another spot on the cheek. Where do you feel that? On his absent thumb,Victor replied. Ramachandran touched the skin between Victor's nose and mouth.His missing index finger was being brushed, Victor said. A spot just belowVictor's left nostril caused the boy to feel a tingling on his left pinkie. Andwhen Victor felt an itch in his phantom hand, scratching his lower face relievedthe itch. In people who have lost a limb, Ramachandran concluded, the brainreorganizes: the strip of cortex that processes input from the face takes overthe area that originally received input from a now missing hand. That's whytouching Victor's face caused brain to "feel" his missing hand.RelatedThe NewMap Of The BrainThere are uncharted worlds inside your head, but science isdrawing a mapThe Mystery of ConsciousnessYou exist, right? Prove it. How 100billion jabbering neurons create the knowledge--or illusion--that you're here6Lessons for Handling StressTake a deep breath. Now exhale slowly. You've justtaken the first step toward managing stress and avoiding burnoutTime Travel inthe BrainWhat are you doing when you aren't doing anything at all?GraphicsFive Paths to Understanding the BrainFrom gruesome ancient rituals to modernpharmacology, mankind had been trying to discover what's really going on insideour heads. A short historyVideoMysteries of ConciousnessSarah Scantlin is aliving medical miracle. An accident injured her brain so severely she shouldhave died, but 20 years later she has regained the ability to speak * SarahScantlin's Dad SpeaksVideoExercise Your BrainDr. Sanjay Gupta tells us howwe can keep our memory as we age and even create new brain cells through mentaland physical exercise * Dr. Gupta Interviews Professor Arthur KramerMoreVideos* Blind Learn To See With Tongue* Helping The Blind To See* A LookInside A Baby's Brain* How Your Brain Handles Stress* Coping With StressSimilarly, because the regions of cortex that handle sensations from the feetabut those that process sensations from the surface of the genitals, some peoplewho have lost a leg report feeling phantom sensations during sex. Ramachandran'swas the first report of a living being knowingly experiencing the results of hisbrain rewiring.THINKING ABOUT THINKINGAS SCIENTISTS PROBE the limits ofneuroplasticity, they are finding that mind sculpting can occur even withoutinput from the outside world. The brain can change as a result of the thoughtswe think, as with Pascual-Leone's virtual piano players. This has importantimplications for health: something as seemingly insubstantial as a thought canaffect the very stuff of the brain, altering neuronal connections in a way thatcan treat mental illness or, perhaps, lead to a greater capacity for empathy andcompassion. It may even dial up the supposedly immovable happiness set point.Ina series of experiments, for instance, Jeffrey Schwartz and colleagues at theUniversity of California, Los Angeles, found that cognitive behavior therapy(CBT) can quiet activity in the circuit that underlies obsessive-compulsivedisorder (OCD), just as drugs do. Schwartz had become intrigued with thetherapeutic potential of mindfulness meditation, the Buddhist practice ofobserving one's inner experiences as if they were happening to someone else.When OCD patients were plagued by an obsessive thought, Schwartz instructed themto think, "My brain is generating another obsessive thought. Don't I know it isjust some garbage thrown up by a faulty circuit?" After 10 weeks ofmindfulness-based therapy, 12 out of 18 patients improved significantly.Before-and-after brain scans showed that activity in the orbital frontal cortex,the core of the OCD circuit, had fallen dramatically and in exactly the way thatdrugs effective against OCD affect the brain. Schwartz called it "self-directedneuroplasticity," concluding that "the mind can change the brain." Where do you feel that? Ramachandran asked. On his left cheek, Victoranswered--and the back of his missing hand. Ramachandran stroked another spot onthe cheek. Where do you feel that? On his absent thumb, Victor replied.Ramachandran touched the skin between Victor's nose and mouth. His missing indexfinger was being brushed, Victor said. A spot just below Victor's left nostrilcaused the boy to feel a tingling on his left pinkie. And when Victor felt anitch in his phantom hand, scratching his lower face relieved the itch. In peoplewho have lost a limb, Ramachandran concluded, the brain reorganizes: the stripof cortex that processes input from the face takes over the area that originallyreceived input from a now missing hand. That's why touching Victor's face causedbrain to "feel" his missing hand.Similarly, because the regions of cortex that handle sensations from the feetabut those that process sensations from the surface of the genitals, some peoplewho have lost a leg report feeling phantom sensations during sex. Ramachandran'swas the first report of a living being knowingly experiencing the results of hisbrain rewiring.THINKING ABOUT THINKINGAS SCIENTISTS PROBE the limits ofneuroplasticity, they are finding that mind sculpting can occur even withoutinput from the outside world. The brain can change as a result of the thoughtswe think, as with Pascual-Leone's virtual piano players. This has importantimplications for health: something as seemingly insubstantial as a thought canaffect the very stuff of the brain, altering neuronal connections in a way thatcan treat mental illness or, perhaps, lead to a greater capacity for empathy andcompassion. It may even dial up the supposedly immovable happiness set point.Ina series of experiments, for instance, Jeffrey Schwartz and colleagues at theUniversity of California, Los Angeles, found that cognitive behavior therapy(CBT) can quiet activity in the circuit that underlies obsessive-compulsivedisorder (OCD), just as drugs do. Schwartz had become intrigued with thetherapeutic potential of mindfulness meditation, the Buddhist practice ofobserving one's inner experiences as if they were happening to someone else.When OCD patients were plagued by an obsessive thought, Schwartz instructed themto think, "My brain is generating another obsessive thought. Don't I know it isjust some garbage thrown up by a faulty circuit?" After 10 weeks ofmindfulness-based therapy, 12 out of 18 patients improved significantly.Before-and-after brain scans showed that activity in the orbital frontal cortex,the core of the OCD circuit, had fallen dramatically and in exactly the way thatdrugs effective against OCD affect the brain. Schwartz called it "self-directedneuroplasticity," concluding that "the mind can change the brain."The same is true when cognitive techniques are used to treat depression.Scientists at the University of Toronto had 14 depressed adults undergo CBT,which teaches patients to view their own thoughts differently--to see a faileddate, for instance, not as proof that "I will never be loved" but as a minorthing that didn't work out. Thirteen other patients received paroxetine (thegeneric form of the antidepressant Paxil). All experienced comparableimprovement after treatment. Then the scientists scanned the patients' brains."Our hypothesis was, if you do well with treatment, your brain will have changedin the same way no matter which treatment you received," said Toronto's ZindelSegal.But no. Depressed brains responded differently to the two kinds oftreatment--and in a very interesting way. CBT muted overactivity in the frontalcortex, the seat of reasoning, logic and higher thought as well as of endlessrumination about that disastrous date. Paroxetine, by contrast, raised activitythere. On the other hand, CBT raised activity in the hippocampus of the limbicsystem, the brain's emotion center. Paroxetine lowered activity there. AsToronto's Helen Mayberg explains, "Cognitive therapy targets the cortex, thethinking brain, reshaping how you process information and changing your thinkingpattern. It decreases rumination, and trains the brain to adopt differentthinking circuits." As with Schwartz's OCD patients, thinking had changed apattern of activity--in this case, a pattern associated with depression--in thebrain.HAPPINESS AND MEDITATIONCOULD THINKING ABOUT THOUGHTS IN A new wayaffect not only such pathological brain states as OCD and depression but alsonormal activity? To find out, neuroscientist Richard Davidson of the Universityof Wisconsin at Madison turned to Buddhist monks, the Olympic athletes of mentaltraining. Some monks have spent more than 10,000 hours of their lives inmeditation. Earlier in Davidson's career, he had found that activity greater inthe left prefrontal cortex than in the right correlates with a higher baselinelevel of contentment. The relative left/right activity came to be seen as amarker for the happiness set point, since people tend to return to this level nomatter whether they win the lottery or lose their spouse. If mental training canalter activity characteristic of OCD and depression, might meditation or otherforms of mental training, Davidson wondered, produce changes that underlieenduring happiness and other positive emotions? "That's the hypothesis," hesays, "that we can think of emotions, moods and states such as compassion astrainable mental skills."With the help and encouragement of the Dalai Lama,Davidson recruited Buddhist monks to go to Madison and meditate inside hisfunctional magnetic resonance imaging (fMRI) tube while he measured their brainactivity during various mental states. For comparison, he used undergraduateswho had had no experience with meditation but got a crash course in the basictechniques. During the generation of pure compassion, a standard Buddhistmeditation technique, brain regions that keep track of what is self and what isother became quieter, the fMRI showed, as if the subjects--experiencedmeditators as well as novices--opened their minds and hearts to others.More interesting were the differences between the so-called adepts and thenovices. In the former, there was significantly greater activation in a brainnetwork linked to empathy and maternal love. Connections from the frontalregions, so active during compassion meditation, to the brain's emotionalregions seemed to become stronger with more years of meditation practice, as ifthe brain had forged more robust connections between thinking and feeling.Butperhaps the most striking difference was in an area in the left prefrontalcortex--the site of activity that marks happiness. While the monks weregenerating feelings of compassion, activity in the left prefrontal swampedactivity in the right prefrontal (associated with negative moods) to a degreenever before seen from purely mental activity. By contrast, the undergraduatecontrols showed no such differences between the left and right prefrontalcortex. This suggests, says Davidson, that the positive state is a skill thatcan be trained.For the monks as well as the patients with depression or OCD,the conscious act of thinking about their thoughts in a particular wayrearranged the brain. The discovery of neuroplasticity, in particular the powerof the mind to change the brain, is still too new for scientists, let alone therest of us, to grasp its full meaning. But even as it offers new therapies forillnesses of the mind, it promises something more fundamental: a newunderstanding of what it means to be human.
By SHARON BEGLEY
It wasa fairly modest experiment, as these things go, with volunteers trooping intothe lab at Harvard Medical School to learn and practice a little five-fingerpiano exercise. Neuroscientist Alvaro Pascual-Leone instructed the members ofone group to play as fluidly as they could, trying to keep to the metronome's 60beats per minute. Every day for five days, the volunteers practiced for twohours. Then they took a test.At the end of each day's practice session, theysat beneath a coil of wire that sent a brief magnetic pulse into the motorcortex of their brain, located in a strip running from the crown of the headtoward each ear. The so-called transcranial-magnetic-stimulation (TMS) testallows scientists to infer the function of neurons just beneath the coil. In thepiano players, the TMS mapped how much of the motor cortex controlled the fingermovements needed for the piano exercise. What the scientists found was thatafter a week of practice, the stretch of motor cortex devoted to these fingermovements took over surrounding areas like dandelions on a suburban lawn.Thefinding was in line with a growing number of discoveries at the time showingthat greater use of a particular muscle causes the brain to devote more corticalreal estate to it. But Pascual-Leone did not stop there. He extended theexperiment by having another group of volunteers merely think about practicingthe piano exercise. They played the simple piece of music in their head, holdingtheir hands still while imagining how they would move their fingers. Then theytoo sat beneath the TMS coil.When the scientists compared the TMS data on thetwo groups--those who actually tickled the ivories and those who only imagineddoing so--they glimpsed a revolutionary idea about the brain: the ability ofmere thought to alter the physical structure and function of our gray matter.For what the TMS revealed was that the region of motor cortex that controls thepiano-playing fingers also expanded in the brains of volunteers who imaginedplaying the music--just as it had in those who actually played it."Mentalpractice resulted in a similar reorganization" of the brain, Pascual-Leone laterwrote. If his results hold for other forms of movement (and there is no reasonto think they don't), then mentally practicing a golf swing or a forward pass ora swimming turn could lead to mastery with less physical practice. Even moreprofound, the discovery showed that mental training had the power to change thephysical structure of the brain.OVERTHROWING THE DOGMAFOR DECADES, THEPREVAILING DOGMA IN neuroscience was that the adult human brain is essentiallyimmutable, hardwired, fixed in form and function, so that by the time we reachadulthood we are pretty much stuck with what we have. Yes, it can create (andlose) synapses, the connections between neurons that encode memories andlearning. And it can suffer injury and degeneration. But this view held that ifgenes and development dictate that one cluster of neurons will process signalsfrom the eye and another cluster will move the fingers of the right hand, thenthey'll do that and nothing else until the day you die. There was good reasonfor lavishly illustrated brain books to show the function, size and location ofthe brain's structures in permanent ink.The doctrine of the unchanging human brain has had profound ramifications. Forone thing, it lowered expectations about the value of rehabilitation for adultswho had suffered brain damage from a stroke or about the possibility of fixingthe pathological wiring that underlies psychiatric diseases. And it implied thatother brain-based fixities, such as the happiness set point that, according to agrowing body of research, a person returns to after the deepest tragedy or thegreatest joy, are nearly unalterable.There are uncharted worlds inside your head, but science is drawing a mapButresearch in the past few years has overthrown the dogma. In its place has comethe realization that the adult brain retains impressive powers of"neuroplasticity"--the ability to change its structure and function in responseto experience. These aren't minor tweaks either. Something as basic as thefunction of the visual or auditory cortex can change as a result of a person'sexperience of becoming deaf or blind at a young age. Even when the brain suffersa trauma late in life, it can rezone itself like a city in a frenzy of urbanrenewal. If a stroke knocks out, say, the neighborhood of motor cortex thatmoves the right arm, a new technique called constraint-induced movement therapycan coax next-door regions to take over the function of the damaged area. Thebrain can be rewired.The first discoveries of neuroplasticity came from studiesof how changes in the messages the brain receives through the senses can alterits structure and function. When no transmissions arrive from the eyes insomeone who has been blind from a young age, for instance, the visual cortex canlearn to hear or feel or even support verbal memory. When signals from the skinor muscles bombard the motor cortex or the somatosensory cortex (which processestouch), the brain expands the area that is wired to move, say, the fingers. Inthis sense, the very structure of our brain--the relative size of differentregions, the strength of connections between them, even theirfunctions--reflects the lives we have led. Like sand on a beach, the brain bearsthe footprints of the decisions we have made, the skills we have learned, theactions we have taken.SCRATCHING A PHANTOM LIMBAN EXTREME EXAMPLE OF HOWCHANGES IN the input reaching the brain can alter its structure is the silencethat falls over the somatosensory cortex after its owner has lost a limb. Soonafter a car crash took Victor Quintero's left arm from just above the elbow, hetold neuroscientist V.S. Ramachandran of the University of California at SanDiego that he could still feel the missing arm. Ramachandran decided toinvestigate. He had Victor sit still with his eyes closed and lightly brushedthe teenager's left cheek with a cotton swab.Time.comCNN.comSearch Archive Wednesday, February 28, 2007 HOME U.S. WORLD BLOGS BUSINESS & TECH HEALTH & SCIENCE ENTERTAINMENT PHOTOS MAGAZINE SPECIALS How The Brain Rewires ItselfFriday, Jan. 19, 2007 By SHARON BEGLEY Enlarge PhotoIllustration for TIME by David PlunkertArticle ToolsPrintEmailReprints (3 of 5)Where do you feel that? Ramachandran asked. On hisleft cheek, Victor answered--and the back of his missing hand. Ramachandranstroked another spot on the cheek. Where do you feel that? On his absent thumb,Victor replied. Ramachandran touched the skin between Victor's nose and mouth.His missing index finger was being brushed, Victor said. A spot just belowVictor's left nostril caused the boy to feel a tingling on his left pinkie. Andwhen Victor felt an itch in his phantom hand, scratching his lower face relievedthe itch. In people who have lost a limb, Ramachandran concluded, the brainreorganizes: the strip of cortex that processes input from the face takes overthe area that originally received input from a now missing hand. That's whytouching Victor's face caused brain to "feel" his missing hand.RelatedThe NewMap Of The BrainThere are uncharted worlds inside your head, but science isdrawing a mapThe Mystery of ConsciousnessYou exist, right? Prove it. How 100billion jabbering neurons create the knowledge--or illusion--that you're here6Lessons for Handling StressTake a deep breath. Now exhale slowly. You've justtaken the first step toward managing stress and avoiding burnoutTime Travel inthe BrainWhat are you doing when you aren't doing anything at all?GraphicsFive Paths to Understanding the BrainFrom gruesome ancient rituals to modernpharmacology, mankind had been trying to discover what's really going on insideour heads. A short historyVideoMysteries of ConciousnessSarah Scantlin is aliving medical miracle. An accident injured her brain so severely she shouldhave died, but 20 years later she has regained the ability to speak * SarahScantlin's Dad SpeaksVideoExercise Your BrainDr. Sanjay Gupta tells us howwe can keep our memory as we age and even create new brain cells through mentaland physical exercise * Dr. Gupta Interviews Professor Arthur KramerMoreVideos* Blind Learn To See With Tongue* Helping The Blind To See* A LookInside A Baby's Brain* How Your Brain Handles Stress* Coping With StressSimilarly, because the regions of cortex that handle sensations from the feetabut those that process sensations from the surface of the genitals, some peoplewho have lost a leg report feeling phantom sensations during sex. Ramachandran'swas the first report of a living being knowingly experiencing the results of hisbrain rewiring.THINKING ABOUT THINKINGAS SCIENTISTS PROBE the limits ofneuroplasticity, they are finding that mind sculpting can occur even withoutinput from the outside world. The brain can change as a result of the thoughtswe think, as with Pascual-Leone's virtual piano players. This has importantimplications for health: something as seemingly insubstantial as a thought canaffect the very stuff of the brain, altering neuronal connections in a way thatcan treat mental illness or, perhaps, lead to a greater capacity for empathy andcompassion. It may even dial up the supposedly immovable happiness set point.Ina series of experiments, for instance, Jeffrey Schwartz and colleagues at theUniversity of California, Los Angeles, found that cognitive behavior therapy(CBT) can quiet activity in the circuit that underlies obsessive-compulsivedisorder (OCD), just as drugs do. Schwartz had become intrigued with thetherapeutic potential of mindfulness meditation, the Buddhist practice ofobserving one's inner experiences as if they were happening to someone else.When OCD patients were plagued by an obsessive thought, Schwartz instructed themto think, "My brain is generating another obsessive thought. Don't I know it isjust some garbage thrown up by a faulty circuit?" After 10 weeks ofmindfulness-based therapy, 12 out of 18 patients improved significantly.Before-and-after brain scans showed that activity in the orbital frontal cortex,the core of the OCD circuit, had fallen dramatically and in exactly the way thatdrugs effective against OCD affect the brain. Schwartz called it "self-directedneuroplasticity," concluding that "the mind can change the brain." Where do you feel that? Ramachandran asked. On his left cheek, Victoranswered--and the back of his missing hand. Ramachandran stroked another spot onthe cheek. Where do you feel that? On his absent thumb, Victor replied.Ramachandran touched the skin between Victor's nose and mouth. His missing indexfinger was being brushed, Victor said. A spot just below Victor's left nostrilcaused the boy to feel a tingling on his left pinkie. And when Victor felt anitch in his phantom hand, scratching his lower face relieved the itch. In peoplewho have lost a limb, Ramachandran concluded, the brain reorganizes: the stripof cortex that processes input from the face takes over the area that originallyreceived input from a now missing hand. That's why touching Victor's face causedbrain to "feel" his missing hand.Similarly, because the regions of cortex that handle sensations from the feetabut those that process sensations from the surface of the genitals, some peoplewho have lost a leg report feeling phantom sensations during sex. Ramachandran'swas the first report of a living being knowingly experiencing the results of hisbrain rewiring.THINKING ABOUT THINKINGAS SCIENTISTS PROBE the limits ofneuroplasticity, they are finding that mind sculpting can occur even withoutinput from the outside world. The brain can change as a result of the thoughtswe think, as with Pascual-Leone's virtual piano players. This has importantimplications for health: something as seemingly insubstantial as a thought canaffect the very stuff of the brain, altering neuronal connections in a way thatcan treat mental illness or, perhaps, lead to a greater capacity for empathy andcompassion. It may even dial up the supposedly immovable happiness set point.Ina series of experiments, for instance, Jeffrey Schwartz and colleagues at theUniversity of California, Los Angeles, found that cognitive behavior therapy(CBT) can quiet activity in the circuit that underlies obsessive-compulsivedisorder (OCD), just as drugs do. Schwartz had become intrigued with thetherapeutic potential of mindfulness meditation, the Buddhist practice ofobserving one's inner experiences as if they were happening to someone else.When OCD patients were plagued by an obsessive thought, Schwartz instructed themto think, "My brain is generating another obsessive thought. Don't I know it isjust some garbage thrown up by a faulty circuit?" After 10 weeks ofmindfulness-based therapy, 12 out of 18 patients improved significantly.Before-and-after brain scans showed that activity in the orbital frontal cortex,the core of the OCD circuit, had fallen dramatically and in exactly the way thatdrugs effective against OCD affect the brain. Schwartz called it "self-directedneuroplasticity," concluding that "the mind can change the brain."The same is true when cognitive techniques are used to treat depression.Scientists at the University of Toronto had 14 depressed adults undergo CBT,which teaches patients to view their own thoughts differently--to see a faileddate, for instance, not as proof that "I will never be loved" but as a minorthing that didn't work out. Thirteen other patients received paroxetine (thegeneric form of the antidepressant Paxil). All experienced comparableimprovement after treatment. Then the scientists scanned the patients' brains."Our hypothesis was, if you do well with treatment, your brain will have changedin the same way no matter which treatment you received," said Toronto's ZindelSegal.But no. Depressed brains responded differently to the two kinds oftreatment--and in a very interesting way. CBT muted overactivity in the frontalcortex, the seat of reasoning, logic and higher thought as well as of endlessrumination about that disastrous date. Paroxetine, by contrast, raised activitythere. On the other hand, CBT raised activity in the hippocampus of the limbicsystem, the brain's emotion center. Paroxetine lowered activity there. AsToronto's Helen Mayberg explains, "Cognitive therapy targets the cortex, thethinking brain, reshaping how you process information and changing your thinkingpattern. It decreases rumination, and trains the brain to adopt differentthinking circuits." As with Schwartz's OCD patients, thinking had changed apattern of activity--in this case, a pattern associated with depression--in thebrain.HAPPINESS AND MEDITATIONCOULD THINKING ABOUT THOUGHTS IN A new wayaffect not only such pathological brain states as OCD and depression but alsonormal activity? To find out, neuroscientist Richard Davidson of the Universityof Wisconsin at Madison turned to Buddhist monks, the Olympic athletes of mentaltraining. Some monks have spent more than 10,000 hours of their lives inmeditation. Earlier in Davidson's career, he had found that activity greater inthe left prefrontal cortex than in the right correlates with a higher baselinelevel of contentment. The relative left/right activity came to be seen as amarker for the happiness set point, since people tend to return to this level nomatter whether they win the lottery or lose their spouse. If mental training canalter activity characteristic of OCD and depression, might meditation or otherforms of mental training, Davidson wondered, produce changes that underlieenduring happiness and other positive emotions? "That's the hypothesis," hesays, "that we can think of emotions, moods and states such as compassion astrainable mental skills."With the help and encouragement of the Dalai Lama,Davidson recruited Buddhist monks to go to Madison and meditate inside hisfunctional magnetic resonance imaging (fMRI) tube while he measured their brainactivity during various mental states. For comparison, he used undergraduateswho had had no experience with meditation but got a crash course in the basictechniques. During the generation of pure compassion, a standard Buddhistmeditation technique, brain regions that keep track of what is self and what isother became quieter, the fMRI showed, as if the subjects--experiencedmeditators as well as novices--opened their minds and hearts to others.More interesting were the differences between the so-called adepts and thenovices. In the former, there was significantly greater activation in a brainnetwork linked to empathy and maternal love. Connections from the frontalregions, so active during compassion meditation, to the brain's emotionalregions seemed to become stronger with more years of meditation practice, as ifthe brain had forged more robust connections between thinking and feeling.Butperhaps the most striking difference was in an area in the left prefrontalcortex--the site of activity that marks happiness. While the monks weregenerating feelings of compassion, activity in the left prefrontal swampedactivity in the right prefrontal (associated with negative moods) to a degreenever before seen from purely mental activity. By contrast, the undergraduatecontrols showed no such differences between the left and right prefrontalcortex. This suggests, says Davidson, that the positive state is a skill thatcan be trained.For the monks as well as the patients with depression or OCD,the conscious act of thinking about their thoughts in a particular wayrearranged the brain. The discovery of neuroplasticity, in particular the powerof the mind to change the brain, is still too new for scientists, let alone therest of us, to grasp its full meaning. But even as it offers new therapies forillnesses of the mind, it promises something more fundamental: a newunderstanding of what it means to be human.
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