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making sense of change
 
 
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Ultimate Self-Improvement - Feature Article from Sept issue of Scientific Amer.
« on: 2003-08-28 10:10:29 » |
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Ultimate Self-Improvement
The brain is still an enigma. But that won't stop us from trying to enhance mental functioning
By Gary Stix
DATE: September 2003 Issue of Scientific American
SOURCE: Scientific American
The Decade of the Brain came and went quietly. For the promoters who conceive and execute campaigns to raise public awareness and research dollars, duration is measured only in days, weeks, months or, rarely, years--never more than a decade. Any longer would exceed the natural life span of the potential audience and sponsors for the message conveyed: The Century of Kidney Disease Awareness? One Hundred Years of Schizophrenia?
Organizers of the Brain Decade coped with the difficulty of deciphering the world's most complex machine by setting out a series of comparatively modest challenges for the 1990s. A representative of the Dana Alliance for Brain Initiatives, which established a series of research objectives for the Decade, assigned generally high marks for meeting the stated goals: the identification of defective genes in familial Alzheimer's and Huntington's disease and the development of new treatments for multiple sclerosis and epilepsy, among other advances.
Left largely untouched was one of science's grand challenges, ranking in magnitude with cosmologists' dream of finding a way to snap together all the fundamental physical forces: we are still nowhere near an understanding of the nature of consciousness. Getting there might require another century, and some neuroscientists and philosophers believe that comprehension of what makes you you may always remain unknowable. Pictures abound showing yellow and orange splotches against a background of gray matter--a snapshot of where the lightbulb goes on when you move a finger, feel sad, or add two and two. These pictures reveal which areas receive increased oxygen-rich blood flow. But despite pretensions to latter-day phrenology, they remain an abstraction, an imperfect bridge from brain to mind.
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The realization that the brain is more changeable than we ever thought has transformed neuroscience.
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Neuroscience, the attempt to deduce how the brain works, has succeeded in unraveling critical chemical and electrical pathways involved in memory, movement and emotion. But reducing the perceptions of a John Coltrane solo or the palette of a Hawaiian sunset to a series of interactions among axons, neurotransmitters and dendrites still fails to capture what makes an event special. Maybe that's why neuroscience fascinates less than it should. Maybe that's also why the Decade of the Brain passed with little notice. It's just too early to tackle the really big questions. Did you know that we are now in the midst of the Decade of Behavior? No? You're not alone.
Even though the Brain Decade came too early to yield the really big answers, intensive worldwide study during the 1990s of the many neural constituents did lend new perspectives on the brain and new tools for enhancing it. Drugmakers know that a pharmaceutical can treat disease effectively, even if they don't know fully how and why it works. The knowledge produced by neuroscientists, not only during the Decade of the Brain but also during the 10 decades that preceded it, has brought us to a juncture where we can begin to devise therapies for neurodegenerative diseases. But the upshot may be more than a drug that helps an Alzheimer's patient remember his name. This special issue of Scientific American describes new insights, not just into improving disordered brains but also into how neuroscience is finding ways to make good brains better.
The most important realization to emerge during the Brain Decade is that the organ being feted is more changeable than we ever thought. Even in maturity, some areas of the brain can renew themselves--a fact astonishingly contrary to a century of neurologists' dogma. That certain areas of the adult brain can generate new cells holds important ramifications for drug development and clinical practice. Careful reactivation of the molecules that foster such neurogenesis might counter the death of neurons that occurs in Alzheimer's and Parkinson's disease.
As more becomes known about this phenomenon, it may help demonstrate how to treat some forms of psychiatric illness. Investigators continue to test the hypothesis that Prozac and other selective serotonin reuptake inhibitors may exert an effect on mood by initiating neurogenesis. Understanding this process and the rewiring of connections that occurs among brain cells may suggest other, more effective agents against depression.
Beyond producing new nerve cells, the brain also rewires itself in response to experience. A deep understanding of so-called neural plasticity may reveal how far we can go with physical therapy, not only to repair the brain but also that torso-length extension of the central nervous system called the spinal cord. Christopher Reeve could not stand up on his 50th birthday, as he had wished. Still, neurologists marvel at the Superman actor's unprecedented recovery of limited movement in his extremities after long incapacitation from spinal injury.
The technological milestone of the past decade was the emergence of magnetic resonance imaging for taking detailed pictures of brains enmeshed in tasks ranging from doing arithmetic to listening to Mozart. Functional MRI, as the technique is known, may not provide a direct route to the essence of our conscious selves, but it could establish the basis for a more definitive form of lie detection than the polygraph and maybe even rudimentary methods of mind reading. More important, the technology, perhaps coupled with genetic testing, will create a more sound basis for diagnosing brain disorders than do current methods that rely on checklists of symptoms.
An understanding of the complex chain of neurotransmitters, "second messengers," transcription factors, genes and other miscellaneous molecules needed to make a long-term memory is leading to drugs that may ultimately help more than those beset with Alzheimer's or more benign forms of dementias that plague the aged. Physicians are sure to write off-label prescriptions for memory enhancers for the pupil preparing for finals or the chief executive readying a speech for the annual shareholders' meeting.
The prospect of enhancing normal brain function is real. And with it will come a host of ethical issues concerning who has access to what. Will a "smart divide" separate an elite who can afford to self-administer a memory pill from the rest of society that copes with rote learning by burning the midnight oil? Neuroscience, perhaps more than any other biological subdiscipline, will force us to confront questions of equity. The Decade of the Brain may have passed with little fanfare, but the scanty knowledge that we now possess--that new brain cells emerge in old adults, for one--has already begun to yield powerful insights for clinical medicine.
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Gary Stix is special projects editor at Scientific American.
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