The Brain is the Final Frontier of Science: by John Horgan (Globe and Mail)

Scientists are closer to mastering the mysteries of the universe than their own brains, says author John Horgan

As a science writer, I am occasionally asked which field of research I would recommend for young, would-be scientists. If I'm in a glass-half-empty mood, my response is, Anything but particle physics. If I'm feeling more upbeat, I'll suggest neuroscience, the study of the brain. The potential payoff from neuroscience is incalculable. The human brain is, in a sense, the source of our most pressing social problems: war, racism, poverty, pollution and crime. According to the World Health Organization, 1.2 billion people suffer from brain disorders such as depression, schizophrenia and substance abuse. The estimated costs of these ailments to the U.S. alone exceed $400-billion, more than the costs of cancer, heart disease and AIDS combined.

Not surprisingly then, 10 years ago, the U.S. Congress designated the 1990's 'the Decade of the Brain.' What may be surprising is that not all neuroscientists were pleased by this honour. Torsten Wiesel, who won a Nobel prize in 1981 for his work on how the brain processes visual data, told me recently that the Decade of the Brain was a foolish idea. 'We need at least a century, maybe even a millennium,' to understand the brain, Prof. Wiesel said.

He was alluding to neuroscience's dark secret.

So far, the reams of data accumulating in journals don't really add up to much. Scientists constantly assure us that they are on the brink of uncovering the key to aggression, depression, addiction, schizophrenia, even consciousness itself. Claims like these could be heard at a major brain-science conference in Toronto just last week. The problem is, brain researchers never quite fulfill their grandiose promises.

But like an Internet company whose stock keeps rising although it has yet to turn a profit, the profession of neuroscience is thriving. The annual budget of the National Institute of Mental Health, the major U.S. funder of neuroscience, more than doubled over the past decade to nearly $1-billion (U.S.) Membership in the U.S. Society for Neuroscience has swelled from 500 when it was founded in 1970 to almost 30,000.

As the conference in Toronto last week made clear, researchers have acquired an astonishingly potent array of tools for probing neural phenomena. They can watch the entire brain in action with positron-emission tomography and magnetic-resonance imaging. They can monitor the minute electrical impulses passing between individual nerve cells with microelectrodes. They can trace the effects of specific genes and neurotransmitters on the brain's functioning. They can model neural phenomena with powerful computers. Brain scientists are getting somewhere. The question is, where? So far, neuroscience has failed either to confirm or to rule our all the competing psychological theories of human nature. Ask 100 different scientists how the mind works, and you will get 100 different answers, ranging from behaviourism and Darwinian theory to computer science and quantum mechanics. Incredibly, some leading neuroscientists still think that some day neuroscience will validate psychoanalysis, the baroque theory and therapy invented by Sigmund Freud over a century ago.

There has also been a troubling schism between neuroscience and what one might expect to be its chief beneficiary, psychiatry. Neuroscientists have found no reliable neurological markers that would illuminate and simplify the diagnosis of diseases such as schizophrenia, bipolar disorder and depression. Most of the medications used to treat mental illness – such as lithium – were discovered through serendipity, and all these drugs have limited effectiveness. Prozac and other supposedly new-and-improved antidepressants are actually no more beneficial than older drugs, such as tricyclics. And drugs in general are not more effective at treating depression and other common emotional disorders than plain old talk therapy. Shock therapy is now making a comeback as a treatment for mental illnesses. Does that seem like a sign of progress?

Arguably the most important discovery from neuroscience so far is that different regions of the brain are specialized for carrying out different functions. The visual cortex contains one set of neurons dedicated to orange-red colours, another to objects with high-contrast diagonal edges and still another to objects moving rapidly from left to right. As recently as the 1950's, many scientists believed that memory is a single -- albeit highly versatile -- function. Since then experiments have revealed that there are many types of memory, each underpinned by its own region of the brain.

Brain-scanning technologies such as magnetic resonance imaging have contributed to scientists' fragmentated view of the brain and mind. Researchers are constantly proclaiming that they have discovered the seat of musical ability, or mathematical talent, or obsessive-compulsive behaviour. This trend is reminiscent of phrenology, the 18th-century pseudo-science that links bumps on the skull to personality traits such as hot-headedness or dishonesty.

As neuroscientists keep subdividing the brain, one question looms ever larger: how does the brain integrate the workings of its highly specialized parts to create the apparent unity of perception and thought that constitutes the mind? This conundrum is sometimes called the binding problem. I prefer another term: the Humpty Dumpty diemma. Like a precocious eight-year-old tinkering with a radio, neuroscientists excel at taking the brain apart, but they have no idea how to put it back together again.

Neuroscientists often object that critiques such as mine are grossly unfair, because their field is 'just beginning.' Actually, the roots of neuroscience run as deep as those of any other field of science. Luigi Galvani showed two centuries ago that nerves emit and respond to electric current, and around the same time Franz Gall proposed the first modular-mind theory, phrenology. William James wrote `Principles of Psychology' in 1890, while Camillo Golgi, Santiago Ramon y Cajal and others were beginning to unravel the structure and function of neurons. The claim that neuroscience is just beginning is based not on the field's actual age but on its productivity.

Optimists hope that neuroscience will be delivered from its current impasse by a genius who discerns patterns and solutions that have eluded all his or her predecessors. The history of other fields of science provides some justification for this hope. During the 1950's, particle physics was mired in a crisis that in some ways resembled the plight of neuroscience. Accelerators seem to generate an exotic new particle almost daily; theorists had no idea how to organize the welter of findings into a cohesive theory. Then a brilliant young theorist named Murray Gell-Mann showed that many of these strange particles were made of a few more fundamental particles called quarks. Out of chaos, order.

But in terms of sheer complexity, particle physics is a child's game -- a 10-piece jigsaw puzzle of Snow White -- compared to neuroscience. Neutrons, electrons and other particles are all identical; a theory that applies to one proton applies to all. But each brain is absolutely unique, and an individual brain can change dramatically when its owner is spanked, learns the alphabet, reads `Thus Spake Zarathustra', takes LSD, falls in love, gets divorced, undergoes Jungian dream therapy or suffers a stroke. I fear that, when it comes to the human brain, there may be no unifying insight that transforms chaos into order.

So why, given my gloomy prognosis for neuroscience, would I recommend it for would-be scientists? Here's why. The problems posed by the human brain are so important, both pragmatically and intellectually, that society will surely never stop funding efforts to solve them. The fact that these problems may also be intractable means that neuroscientific research -- unlike particle physics -- may last forever. Neuroscience is the field of the future, and it always will be.



John Horgan is the author of The End of Science and The Undiscovered Mind. He lives in Garrison, N.Y.