Shocking Science
Shattered Nerves: How Science Is Solving Modern Medicine’s Most Perplexing Problem by Victor D. Chase. Johns Hopkins University Press, 2006 ($27.50)
Almost from the time electricity was discovered, scientists suspected it was involved in human and animal motion. They used electricity to make frogs’ legs jump and, less successfully, to try to reanimate the dead.
Today modern science can use a judicious jolt of electricity to restart a stopped heart under the right circumstances. Much more difficult has been the attempt to use implanted electrodes to restore function to body parts affected by nerve damage.
Science and technology writer Victor D. Chase tells the story of the effort to create these “neural prostheses,” providing an exhaustive look at the researchers and the technological innovations that have returned hearing and movement to nerve-damaged patients. Nerve impulses are electrochemical, and an obvious solution to damage would be to bypass the injured site and stimulate the nerves directly by running current through an electrode.
But what is simple in principle is hard in practice. Even the smallest electrodes are blunt instruments compared with the nerves they are trying to stimulate. Researchers would like to excite each nerve individually and to develop a controller as finely tuned as the human brain. What they often settle for are a few electrodes affecting a lot of nerves with relatively unsophisticated controllers.
Yet there have been successes. Probably the most familiar story is that of the cochlear implant, which activates the auditory nerves in the cochlea and has restored partial hearing to tens of thousands of people around the world.
Others have had success with systems that trigger leg muscles so a paralyzed person can stand up or that stimulate the muscles of the hand so a person with partial paralysis can grasp an object. (The devices are activated with shoulder, arm or head movements.) Still other implants target the nerves in the eyes of blind people so they can discern light and dark and even some simple patterns.
This is dramatic stuff, although the detailed profiles of researchers and patients, as well as the nuts-andbolts descriptions of the various technologies, might overwhelm some readers. Nevertheless, the book is a valuable introduction to an important subject. —Kurt Kleiner
Maestro of the Mind
The Genius Engine: Where Memory, Reason, Passion, Violence, and Creativity Intersect in the Human Brain by Kathleen Stein. Wiley, 2007 ($27.95)
As scientists continue to unlock the secrets of the human brain, the prefrontal cortex (PFC) has moved to center stage. Mounting research indicates that this brain region, situated right behind our forehead, has the power to suppress impulses and can override logical decisions when they conflict with beliefs or emotions. The PFC is the seat of genius, “the engine of choice, flexibility, decision-making, and foresight,” which, Kathleen Stein argues, puts it “at the core of our humanity.”
Stein, a neuroscience journalist, uses dozens of interviews with a wide range of brain scientists as the basis for her survey of recent research on the PFC’s diverse functions. The book has no overarching story. Nevertheless, through a plethora of case studies and examples, Stein builds up a panoramic picture of the many roles of the PFC—from planning ahead to suppressing urges, from committing violent acts to understanding jokes.
We learn about a patient whose PFC injury affected his judgment, causing the well-educated, cultured man to slip inappropriate remarks—such as graphic details about his sex life—into professional conversations.
One brain-imaging study illustrates the PFC’s role in inhibiting false applications of deductive reasoning. For example, scientists asked volunteers to assess the validity of the syllogism “some wars are justifi ed; all wars involve raping of women; some raping of women is justifi ed.” They observed rapid firing of the PFC when volunteers judged the statement as false despite its presentation as a logical argument. Stein also introduces us to the PFC’s function as the memory of the future. Not only is it the place where expected scenarios are first played out, it is also the center of forward-looking fantasies, such as dreams of winning the lottery or a Nobel Prize.
In the concluding chapter, “The Rise of the Machine Genius,” we get a glimpse into the world of artificial intelligence. We learn that researchers have already had some success in designing machines that simulate PFC neuronal function and that have the ability to perform problem-solving and reasoning operations, which suggests these electronic brains could be harnessed to test different theories of mental disorders. Stein seems convinced that, ultimately, scientists will succeed in deciphering the complete wiring pattern of the human brain and in building a functioning replica of it. —Nicole Branan
Neuron Renovation
The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge. Viking, 2007 ($24.95)
For most of the 20th century, neuroscientists believed that adult brains, unlike those of children, could not grow new neurons or form new networks among existing brain cells. According to this view, if part of the brain were damaged or underdeveloped, the functions of that part would be lost.
But in the past couple of decades, scientists have compiled formidable evidence of the persistence throughout adulthood of neuroplasticity, the brain’s capacity for structural and functional change. Sophisticated scanning technologies reveal brains to be more flexible and dynamic than traditionally thought. Moreover, new therapies and exercises draw on neuroplasticity to counteract conditions ranging from strokes and balance disorders to learning disabilities and age-related cognitive decline.
Norman Doidge, a research psychiatrist and psychoanalyst at Columbia University and the University of Toronto, recounts these developments through vignettes of the scientists, physicians and patients, as well as animal and human research subjects, at the forefront of the science of neuroplasticity. The result is an absorbing and encouraging depiction of the brain’s potential to overcome debilities and diseases.
The book features protagonists such as Paul Bach-y-Rita, a University of Wisconsin–Madison physician and biomedical engineer. By placing a motion-sensing device on the tongue of patient Cheryl Schiltz, Bach-y-Rita (who died in late 2006) enabled Schiltz to regain the sense of balance she had lost as the result of inner-ear damage. The device sparked small electric charges that felt like champagne bubbles on her tongue, letting her know if she was leaning too far one way or another. In time, her brain was retrained to keep her body upright, letting her maintain her balance without the tongue device.
Other neuroplasticity pioneers discussed include psychologist Edward Taub, whose “constraint-induced” therapy involves binding the unaffected limbs of stroke patients so they will relearn to use their affected limbs; neuroscientist Michael Merzenich, whose computer-learning programs help kids with autism; and educator Barbara Arrowsmith Young, who developed mental exercises, such as reading cards with complex clock faces, to overcome her own early difficulties with abstract thought. Doidge also profi les Michelle Mack, who was born without a left brain hemisphere and whose right brain handles language functions normally done by the left.
Despite the book’s ebullient subtitle, Doidge’s tone is one of measured optimism. He notes that neuroplasticity also has its downsides, as when amputees’ brains rewire to produce phantom pains or, more prosaically, when people learn bad habits. —Ken Silber
Oops, Therefore I Am
The Accidental Mind: How Brain Evolution Has Given Us Love, Memory, Dreams, and God by David J. Linden. Belknap Press, 2007 ($25.95)
From its seat inside our skull, the brain manages our thoughts and emotions, files away our memories, makes our decisions and controls our body. Clearly, only a masterpiece of design would be capable of performing such an enormous breadth of complex tasks, right? Wrong, says David J. Linden, who contends that thinking of the brain as a beautifully engineered, optimized device is “pure nonsense.”
In The Accidental Mind, the Johns Hopkins University neuroscientist shows us that the brain is a cobbled-together mess that was formed over millions of years of evolution. He argues that it is precisely the lack of optimized design that has led to some of our most cherished abilities: to feel love, to have memories and dreams, and to create religious concepts.
Linden’s story is captivating. Chapter by chapter, he builds his compelling arguments, starting with a close examination of the human brain’s structural flaws and the short comings of its parts. The ancient design of our neurons makes them slow and inefficient processors, he contends, so the brain requires an extraordinary amount of them and needs to interconnect them with even more synapses. The brain’s neuronal network is too big to have its point-to-point wiring diagram explicitly encoded in our genes, which is why we are born with only a moderately developed brain and have to complete the fine-scale wiring by learning from experience during our species’ unusually long childhood. That alone, Linden asserts, is the reason for the existence of our memories and, ultimately, for the development of our individuality.
Religious thought and practice, Linden reasons, result from the general tendency of our brain to mess with incoming data to create coherent, gap-free stories. Our brain makes visual perception seem continuous and flowing, for example, even though the pictures our neurons receive through our rapidly jumping eyeballs are not. Linden believes that it is solely because of poor brain design that this narrative-constructing function is turned on at all times, whether it is relevant for the particular task at hand or not.
In a situation where we lack evidence or a logical explanation—when contemplating the reason for our existence, say—we are driven to invent one, even if it leads humanity to appeal to a supernatural, godly power. —Nicole Branan
Shattered Nerves: How Science Is Solving Modern Medicine’s Most Perplexing Problem by Victor D. Chase. Johns Hopkins University Press, 2006 ($27.50)
Almost from the time electricity was discovered, scientists suspected it was involved in human and animal motion. They used electricity to make frogs’ legs jump and, less successfully, to try to reanimate the dead.
Today modern science can use a judicious jolt of electricity to restart a stopped heart under the right circumstances. Much more difficult has been the attempt to use implanted electrodes to restore function to body parts affected by nerve damage.
Science and technology writer Victor D. Chase tells the story of the effort to create these “neural prostheses,” providing an exhaustive look at the researchers and the technological innovations that have returned hearing and movement to nerve-damaged patients. Nerve impulses are electrochemical, and an obvious solution to damage would be to bypass the injured site and stimulate the nerves directly by running current through an electrode.
But what is simple in principle is hard in practice. Even the smallest electrodes are blunt instruments compared with the nerves they are trying to stimulate. Researchers would like to excite each nerve individually and to develop a controller as finely tuned as the human brain. What they often settle for are a few electrodes affecting a lot of nerves with relatively unsophisticated controllers.
Yet there have been successes. Probably the most familiar story is that of the cochlear implant, which activates the auditory nerves in the cochlea and has restored partial hearing to tens of thousands of people around the world.
Others have had success with systems that trigger leg muscles so a paralyzed person can stand up or that stimulate the muscles of the hand so a person with partial paralysis can grasp an object. (The devices are activated with shoulder, arm or head movements.) Still other implants target the nerves in the eyes of blind people so they can discern light and dark and even some simple patterns.
This is dramatic stuff, although the detailed profiles of researchers and patients, as well as the nuts-andbolts descriptions of the various technologies, might overwhelm some readers. Nevertheless, the book is a valuable introduction to an important subject. —Kurt Kleiner
Maestro of the Mind
The Genius Engine: Where Memory, Reason, Passion, Violence, and Creativity Intersect in the Human Brain by Kathleen Stein. Wiley, 2007 ($27.95)
As scientists continue to unlock the secrets of the human brain, the prefrontal cortex (PFC) has moved to center stage. Mounting research indicates that this brain region, situated right behind our forehead, has the power to suppress impulses and can override logical decisions when they conflict with beliefs or emotions. The PFC is the seat of genius, “the engine of choice, flexibility, decision-making, and foresight,” which, Kathleen Stein argues, puts it “at the core of our humanity.”
Stein, a neuroscience journalist, uses dozens of interviews with a wide range of brain scientists as the basis for her survey of recent research on the PFC’s diverse functions. The book has no overarching story. Nevertheless, through a plethora of case studies and examples, Stein builds up a panoramic picture of the many roles of the PFC—from planning ahead to suppressing urges, from committing violent acts to understanding jokes.
We learn about a patient whose PFC injury affected his judgment, causing the well-educated, cultured man to slip inappropriate remarks—such as graphic details about his sex life—into professional conversations.
One brain-imaging study illustrates the PFC’s role in inhibiting false applications of deductive reasoning. For example, scientists asked volunteers to assess the validity of the syllogism “some wars are justifi ed; all wars involve raping of women; some raping of women is justifi ed.” They observed rapid firing of the PFC when volunteers judged the statement as false despite its presentation as a logical argument. Stein also introduces us to the PFC’s function as the memory of the future. Not only is it the place where expected scenarios are first played out, it is also the center of forward-looking fantasies, such as dreams of winning the lottery or a Nobel Prize.
In the concluding chapter, “The Rise of the Machine Genius,” we get a glimpse into the world of artificial intelligence. We learn that researchers have already had some success in designing machines that simulate PFC neuronal function and that have the ability to perform problem-solving and reasoning operations, which suggests these electronic brains could be harnessed to test different theories of mental disorders. Stein seems convinced that, ultimately, scientists will succeed in deciphering the complete wiring pattern of the human brain and in building a functioning replica of it. —Nicole Branan
Neuron Renovation
The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge. Viking, 2007 ($24.95)
For most of the 20th century, neuroscientists believed that adult brains, unlike those of children, could not grow new neurons or form new networks among existing brain cells. According to this view, if part of the brain were damaged or underdeveloped, the functions of that part would be lost.
But in the past couple of decades, scientists have compiled formidable evidence of the persistence throughout adulthood of neuroplasticity, the brain’s capacity for structural and functional change. Sophisticated scanning technologies reveal brains to be more flexible and dynamic than traditionally thought. Moreover, new therapies and exercises draw on neuroplasticity to counteract conditions ranging from strokes and balance disorders to learning disabilities and age-related cognitive decline.
Norman Doidge, a research psychiatrist and psychoanalyst at Columbia University and the University of Toronto, recounts these developments through vignettes of the scientists, physicians and patients, as well as animal and human research subjects, at the forefront of the science of neuroplasticity. The result is an absorbing and encouraging depiction of the brain’s potential to overcome debilities and diseases.
The book features protagonists such as Paul Bach-y-Rita, a University of Wisconsin–Madison physician and biomedical engineer. By placing a motion-sensing device on the tongue of patient Cheryl Schiltz, Bach-y-Rita (who died in late 2006) enabled Schiltz to regain the sense of balance she had lost as the result of inner-ear damage. The device sparked small electric charges that felt like champagne bubbles on her tongue, letting her know if she was leaning too far one way or another. In time, her brain was retrained to keep her body upright, letting her maintain her balance without the tongue device.
Other neuroplasticity pioneers discussed include psychologist Edward Taub, whose “constraint-induced” therapy involves binding the unaffected limbs of stroke patients so they will relearn to use their affected limbs; neuroscientist Michael Merzenich, whose computer-learning programs help kids with autism; and educator Barbara Arrowsmith Young, who developed mental exercises, such as reading cards with complex clock faces, to overcome her own early difficulties with abstract thought. Doidge also profi les Michelle Mack, who was born without a left brain hemisphere and whose right brain handles language functions normally done by the left.
Despite the book’s ebullient subtitle, Doidge’s tone is one of measured optimism. He notes that neuroplasticity also has its downsides, as when amputees’ brains rewire to produce phantom pains or, more prosaically, when people learn bad habits. —Ken Silber
Oops, Therefore I Am
The Accidental Mind: How Brain Evolution Has Given Us Love, Memory, Dreams, and God by David J. Linden. Belknap Press, 2007 ($25.95)
From its seat inside our skull, the brain manages our thoughts and emotions, files away our memories, makes our decisions and controls our body. Clearly, only a masterpiece of design would be capable of performing such an enormous breadth of complex tasks, right? Wrong, says David J. Linden, who contends that thinking of the brain as a beautifully engineered, optimized device is “pure nonsense.”
In The Accidental Mind, the Johns Hopkins University neuroscientist shows us that the brain is a cobbled-together mess that was formed over millions of years of evolution. He argues that it is precisely the lack of optimized design that has led to some of our most cherished abilities: to feel love, to have memories and dreams, and to create religious concepts.
Linden’s story is captivating. Chapter by chapter, he builds his compelling arguments, starting with a close examination of the human brain’s structural flaws and the short comings of its parts. The ancient design of our neurons makes them slow and inefficient processors, he contends, so the brain requires an extraordinary amount of them and needs to interconnect them with even more synapses. The brain’s neuronal network is too big to have its point-to-point wiring diagram explicitly encoded in our genes, which is why we are born with only a moderately developed brain and have to complete the fine-scale wiring by learning from experience during our species’ unusually long childhood. That alone, Linden asserts, is the reason for the existence of our memories and, ultimately, for the development of our individuality.
Religious thought and practice, Linden reasons, result from the general tendency of our brain to mess with incoming data to create coherent, gap-free stories. Our brain makes visual perception seem continuous and flowing, for example, even though the pictures our neurons receive through our rapidly jumping eyeballs are not. Linden believes that it is solely because of poor brain design that this narrative-constructing function is turned on at all times, whether it is relevant for the particular task at hand or not.
In a situation where we lack evidence or a logical explanation—when contemplating the reason for our existence, say—we are driven to invent one, even if it leads humanity to appeal to a supernatural, godly power. —Nicole Branan
