Alpha Books produces the popular series of The Complete Idiot’s Guides (CIGs). According to their Web site (www.idiotsguides.com), there are more than 400 titles in print on personal ﬁnance, business, health and ﬁtness, foreign languages, New Age tantric sex, improving amorous relationships, computer operating systems and software, and other topics. I read the one on being a grandparent and found it an amusing compilation of common wisdom. Thus far, however, CIGs have not ventured heavily into science, and if Understanding the Brain is an example of their quality control, maybe they should steer clear of it.
Mitchell Bard has written two earlier CIGs, one on World War II, the other on Middle East conflicts. He tells us that he convinced his father, a neurosurgeon in Northern California, to co-author this CIG to provide readers an opportunity to learn “not only the basics about the brain, but also some of the more sophisticated concepts without being overwhelmed.” Their goal here is unassailable: “a greater appreciation for the amazing and mysterious organ that is allowing you to read and comprehend these words.” We neuroscientists want people to understand the brain and the work we do. If the Bards found the long list of books already out there too complicated, ponderous, or detailed, and thought they could do a better job, more power to them. But be warned at the start that these good intentions resulted in a work that falls far short of minimal intellectual standards. Sloppy scholarship pervades this book, and the level of discourse, while simple, falls well below a typical Cliff Notes in substantive content. Even worse, when the authors try to explain complex aspects of brain and behavior in simple terms, far too often, sadly, they are plain wrong.
The best section of the book is Part 1, four brief chapters on how scientists began to understand the brain. Chapters 2 and 3 emerged unscathed from my scrutiny, but no others did. Unfortunately, when the authors leave well-trod and oft-reported history, their forays into the details of brain biology rapidly deteriorate. Their description of how the human brain develops is an attempt to convey the essentials in very simple terms, but they use terminology that has not yet been explained and offer no illustrations to clarify. No reader new to this material will be able to follow it. Furthermore, their assertion (page 8) that “although most of the neurons are in place before birth, they are not wired together” is wrong. In the human brain, connections are legion before birth, with many more to come.
Their ﬁrst ﬁgure (page 8) shows a standard midline view of the right side of the adult human brain from the perspective of the left ear. Here, they mislabel the third ventricle as the hypothalamus, placing the thalamus below the hypothalamus (it is the other way around), and do not describe or deﬁne any of the brain parts shown for another 50 pages. They use exactly the same drawing on page 59, with the ventricles now labeled; but the upper part of the third ventricle is mislabeled as the lateral ventricle, which would not be visible from the mid-line. The simple depiction of the skull and meninges on page 58 makes it appear that the dura mater and the arachnoid are the same layer of tissue, while the tag line from “pia mater” is really in the subdural space. Why are these terms even in here? The authors want to make the point that because the space between these membranes is ﬁlled with cerebrospinal ﬂuid, the brain is surrounded by a hydraulic shock absorber. They do use the phrase “shock absorber” for the membranes, but do not say how it works.
FROM SIMPLIFICATION TO SIMPLY WRONG
Their simpliﬁcation of cell biology is no better. Yes, “neurons are the basic building blocks of the nervous system,” and yes, neurons are “cells consisting of a cell body, axon and dendrites,” but unless you already know that neurons are linked in functional circuits, and how the function of an axon (to send out impulses) differs from that of a dendrite (to receive signals coming in from connected neurons), those simple sentences will not help much. Extolling President George H. Bush’s declaration of the Decade of the Brain in 1990, they conclude that “thanks to improvements in microscopes, many of the greatest advances were made at the molecular level”—an outright misunderstanding of how molecular advances were made. They also incorrectly conclude from recent genetics discoveries that Alzheimer’s and Parkinson’s diseases are as inheritable as Huntington’s, which is far from true.
The authors repeat the long-disproved contention that human brains start to lose neurons in early adulthood, and even tell us that the rate of loss is 10,000 neurons per day.
The authors repeat the long-disproved contention that human brains start to lose neurons in early adulthood, and even tell us that the rate of loss is 10,000 neurons per day. The scientiﬁc literature and accurate introductory books clearly state that, with few exceptions (the dopamine-containing neurons that die in Parkinson’s disease are one), most parts of the healthy human brain—including the thinking and remembering parts, the cerebral cortex, and the hippocampal formation—do not lose neurons with age unless there is trauma or stroke.
The history of neuroscience is replete with colorful characters whose basic biographies are well known, but apparently not to the Bards. Alois Alzheimer was not a professor of psychology, as they claim (page 44); he was a medical doctor, psychiatrist, and noted neuropathologist. And it was in 1906, not 1907, that he presented his postmortem observations describing the rapid progression of dementia in a 51-year-old woman. Based on that examination, Alzheimer recorded the ﬁrst observations on the neuronal tangles that became the hallmark of what was soon called Alzheimer’s disease. I was curious how the Bards could get their facts wrong, given that Alzheimer’s history is so frequently reported, so I consulted my favorite omniscience site, Google. The Bards must have done so, as well; both they and the University of Illinois Department of Neurology Web site that pops up at the top of Google’s list of sites say that Alzheimer was a psychologist, although none of the other sites makes this error.
I was curious how the Bards could get their facts wrong, given that Alzheimer’s history is so frequently reported, so I consulted my favorite omniscience site, Google.
Two paragraphs later, the Bards miss again: Joseph Erlanger and Herbert Gasser, who indeed were chosen for the Nobel Prize in Physiology or Medicine (in 1944), were scarcely contemporaries of Alzheimer. And, contrary to the Bards’ interpretation, their work was not on the release of chemicals by excited neurons, but on the relationship between the diameters of nerve fibers in the peripheral nervous system and the rate at which their action potentials are propagated. Thick fibers permit travel at rates up to 100 meters per second, the thinnest fibers at less than 2 meters per second. The Bards do describe how fast our nerves can conduct their activity, converting the speeds to a simpler-to-grasp (at least for Americans) miles per hour, but they ascribe this discovery to the German physiologist Emil DuBois-Raymond. Working as he did in the middle of the nineteenth century, DuBois-Raymond had no possibility of measuring how rapidly nerves conduct; he is credited with demonstrating that the activity of nerves and muscles is associated with a wave of negative potential, later termed depolarization.
They do accurately characterize the disagreements between Camillo Golgi and Santiago Ramon y Cajal over whether the brain is a gigantic network of physically continuous cells (Golgi’s “reticularist” view) or interconnected separate neurons (Cajal’s “neuronal” view). While it is true that Cajal reported “gaps” at the point where the axon of one neuron approaches another to which he inferred it was connected, Cajal did not name these gaps “synapses.” That term was ﬁrst applied by another Nobelist, Sir Charles Sherrington. What Cajal saw, in fact, was an artifact of the staining method that he borrowed from Golgi. The size of the gap at a real synapse is so small that it could not be seen until the late 1950s, when the electron microscope was developed and applied to the study of the nervous system. The Bards portray a synapse schematically on page 81, but with no indications of the true dimensions of any of the structures or the synaptic gap.
On page 45, the Bards compound their erroneous reporting of the history of neuroscience when they describe the well-known story of the Nobelist Otto Loewi. Loewi’s inspiration for the experiments that led to his discovery that autonomic nerves control the cardiac rhythm by secreting acetylcholine (and thus establishing that neurons speak to their targets chemically) came during a dream. They draw from his work “that one of the ways nerve impulses are transmitted is chemically.” While it may be permissible to refer to a synaptic vesicle laden with transmitters as a “boat” (page 81), those boats do not carry “electrical messages to other structures” at all, but are the key intermediates in the conversion to chemical signaling at the synapse. Their list of the most “common” neurotransmitters (page 82) does not include the two that provide the signals for well over 90 percent of all brain synapses: glutamate and Gamma-amino-butyrate (better known as GABA). Furthermore (page 124), the brainstem neurons that produce noradrenaline (norepinephrine in the New World) do not produce REM sleep; these neurons are in fact totally inactive during REM sleep.
The authors do much better recounting the history of neurosurgery, devoting almost two pages to an account of two pioneer neurosurgeons and almost all of Chapter 22 to interesting cases reported by Bard senior, but neurology is essentially neglected as a medical profession. They limit their views of psychiatry to early Freudian psychoanalysis and a few of the drugs in use today, but they avoid any mechanistic explanation of how those drugs are thought to work. Their peculiar intellectual position here (page 280)—that the widespread development of drugs to treat depression has “helped stimulate a dramatic rise in the number of people treated for depression in general and those using antidepressants in particular”—leaves me wondering whether they consider such a rise as a good or a bad outcome. Most psychiatrists I know maintain that depression is still under-diagnosed and under-treated.
The Bards show their disdain for antipsychotic drugs when they refer to “phenothiazines” (the chemical class of the ﬁrst of the modern antipsychotic agents) as a “urinary antiseptic” (page 225), and imply that its use can cause Parkinson’s disease. The truth is that, because this class of drugs work by blocking the chemical messages delivered by secretion of dopamine, when that transmitter is already in short supply, as happens in Parkinson’s disease, taking such drugs can make it worse. They can also cause a related movement disorder, called tardive dyskinesia, which the Bards mention much later.
Their description (page 240) of how alcohol acts on the brain’s reward circuits would be funny if it were intended as a spoof, and if this reviewer and his colleagues had not spent two decades on such research. They write:
Interestingly, a low dose of alcohol stimulates brain activity. Alcohol specifically increases the activity of GABA, an inhibiting neurotransmitter that affects the release of dopamine. Alcohol prevents the inhibition effect of GABA and therefore increases the production of dopamine. By inhibiting the effect of GABA, alcohol causes more dopamine…to be released.
Now, you tell me: Does alcohol increase or decrease the effects of GABA? What they needed to explain is that dopamine neurons are normally held in check by nearby GABA neurons. In the presence of low intoxicating blood levels of alcohol, those GABA neurons are inhibited because they are sensitive to their own GABA and that which they receive from other inhibitory GABA neurons. As a result, the dopamine neurons are disinhibited. The release of dopamine at a speciﬁc forebrain location called the nucleus accumbens is thought to be a pleasure signal to the imbiber.
PLASTIC EGGS BENEDICT
My ﬁnal examples of slipshod storytelling have to do with two concepts that the authors bring up repeatedly: the “limbic system” and the rate at which neurons under certain conditions use glucose, as inferred from PET studies. According to the Bards (page 72), “the limbic system connects the cortex and the midbrain.” Curious readers do not learn that the “limbic lobe” was conceived as a hypothetical lobe for processing olfactory information and was composed of all the brain structures around the inner circle of the cortex: the cingulate cortex, the hippocampus, and the basal ganglia. These structures were lumped into a “system” because they are close together.
When modern methods of tracing interneuronal connections emerged in the 1970s, it became clear that these structures were adjacent but not directly interconnected— and so unlikely to be the reward/defense/ reproduction circuits the limbic system myth has perpetuated.
The Bards also rave over PET studies of brain activity. But they never illustrate a PET scan, nor deﬁne what positrons are, nor how the results are interpreted.
The Bards also rave over PET studies of brain activity. But they never illustrate a PET scan, nor deﬁne what positrons are, nor how the results are interpreted. Worse, they describe glucose utilization rates for brain regions in terms of the colors of the ranking scales: brain sites using the most glucose are mapped in hot colors, red>yellow>white, and the places using the least are mapped in cool colors, white>light blue>dark blue. Pity the reader who wonders where the colors they describe come from, not realizing they are simply arbitrary representations of the computer data. Regrettably, the authors also lump glucose utilization data with oxygen utilization data. But maps of oxygen use can track events that occur during very brief functional tasks (like visualizing a movement in your mind without moving), while glucose accumulation methods require tasks to produce changes in brain activity that persist for several minutes.
Apparently, all CIGs come with “extras.” For readers of Understanding the Brain there are Words of Wisdom, IQ Points, Code Blue notes, and Gray Matter notes. None of the Words of Wisdom were either very good or comprehensive, and all are repeated verbatim in the glossary. Because of their reluctance to engage substantive issues, the authors ﬁll space with list after meaningless list: 7 categories of odors, 4 kinds of dyslexia, 3 kinds of brain message encoding, 8 kinds of intelligence, 16 kinds of mental disorders (straight from the American Psychiatric’s Diagnostic and Statistical Manual), 10 kinds of phobias, 14 forms of (nondrug) psychotherapy, and the transcript of Ronald Reagan’s admission of Alzheimer’s disease.
Several years ago, I took my wife, daughter, and father-in-law along on a trip to Japan, where I attended a pharmacology congress. After several days spent trying to adapt to the local food, they were desperate for familiar cooking, so we went to the Tokyo Hilton for Sunday brunch. There we saw the same plastic replicas of the Western food offerings that Japanese restaurants display for their dishes. My daughter spotted the Eggs Benedict replica and ordered that dish. When the food came, it looked exactly like the plastic replica, and tasted like plastic, too. The CIG To Understanding the Brain is a replica of a real brain book. It has chapters on all the right parts of the brain and their functions, and vignettes on the major players who got us to the present points of understanding, but the information is far too often wrong or misleading. Worse, the authors fail to indicate the why’s and wherefore’s behind the facts.
The goal of explaining the brain to those who are curious but not academically trained in the science remains an important quest for all of us who practice the arts of neuroscience and seek to communicate progress to the public, interested foundations, and the government. Were readers to attend the annual meeting of the Society for Neuroscience, and have the chance to eavesdrop as scientists explain their latest results to one another, most would certainly become confused quickly as the jargon, abbreviations, and assumptions of prior knowledge accumulated. The brain and its parts are unquestionably complicated. The more science learns about how the brain assembles itself during development, modiﬁes itself as we experience the world around ourselves, and communicates that world through billions of chemically-signalled living circuits, the more complicated our concept of “the brain” becomes.
My awareness of plain-spoken neuroscience came through my work at an institution heavily dependent on private benefactors. My president would bring them around to see what we were doing as a bait to attract their interest, and we had very brief times to make our spiels with impact. My advice to my colleagues was to consider them as investment bankers who may not know science, but know how to evaluate human effort, logical thinking, and enthusiastic motivation. Reduce the complexity of the problem you are trying to solve by describing it so your mother and your banker can understand it. If you cannot reach that degree of simpliﬁcation while keeping the quest accurate, maybe you do not really understand what you are doing.
Clearly the combination of wise experienced scientist and proﬁcient science journalist can produce clarity with accuracy. Maybe the CIGs should consider that next time.
All of which is not to say that there are not already excellent and inspiring books on the brain for non-biology majors. One of the best is Brain Facts, published electronically and in print by the Society for Neuroscience, and available for free as a Portable Document File at the Society’s Web site, http://apu.sfn.org/content/ Publications/BrainFacts/index.html, designed speciﬁcally to communicate the substance and challenges of the science to the lay public. Two relatively economical books on the brain’s structure are also worthwhile mentioning, not only for their ability to communicate the human brain’s structural complexities simply, but for clues on how they did that. Walle J.H. Nauta was considered the pre-eminent neuroanatomist of the second half of the twentieth century. His book Fundamental Neuroanatomy (MIT Press, 1986) with the Scientiﬁc American editor Michael Fiertag not only describes the assembly and the intrinsic circuits for senses and movement, it compares brains across species accurately and clearly without requiring signiﬁcant prior knowledge. Two highly distinguished brain and behavior researchers, Marion C. Diamond and Arnold B. Scheibel, collaborated with the science writer and photographer Lawrence M. Elson to produce the Human Brain Coloring Book (Barnes and Noble, 1985). Completion of the exercises and perusal of the accompanying text will provide insight easily to a degree that many advanced students would envy. Clearly the combination of wise experienced scientist and proﬁcient science journalist can produce clarity with accuracy. Maybe the CIGs should consider that next time.
From The Complete Idiot’s Guide to Understanding the Brain by Arthur S. Bard, M.D., and Mitchell G. Bard, Ph.D. © 2002 Arthur S. Bard,M.D., and Mitchell G. Bard, Ph.D. Reprintedwith permission of Alpha Books.
FROM STONE AGE TO SCULPTORS Humans have always been fascinated with brain anatomy and function. Even ancient cave petroglyphs show a caveman striking another over the head with a large club. The caveman must have been aware of some type of brain function because he realized this act would render the individual unconscious or dead. Aha! The first neurophysiological experiment!
PREHISTORIC BRAIN SURGERY Given that the brain is perhaps the most complex machine in the universe, you may be surprised to learn that brain surgery is one of the oldest medical treatments. Apparently, humans didn’t start out trying to heal each other with herbs or magical potions or leeches. Instead, they got right to work drilling skulls.
Not only is there evidence of brain surgery dating back to about 7000 B.C.E. (the late stone age), but also these were successful operations!
Archaeologists have discovered preserved skulls with holes in them and some surgical instruments of these medical pioneers in France, but brain surgery was not a strictly European phenomenon: it was practiced throughout the world. Evidence of brain surgery in Africa dates to 3000 B.C.E., and as early as 2000 B.C.E., Peruvians predating the Incas practiced the same form of surgery, which is known as “trephining.”
This method of brain surgery was used to cure people of mental illness, headaches, epilepsy, and other illnesses as well as for spiritual and magical reasons. The practice continued to be used for centuries and was still in vogue in Europe as late as the sixteenth century.
Sometimes multiple holes were drilled in a single skull, but they were generally made with surprising neatness given the crude nature of the tools, which included wooden sticks with flint tips, bronze knives, and scalpels of copper or volcanic glass. Today, holes are still drilled in people’s skull to relieve pressure on the brain, to repair fractures, to do biopsies, and to gain access to a tumor or blood vessel abnormality, but precision, electric or airpowered drills and saws are used for modern brain surgery.
How do we know that these patients with holes in their head survived, let alone were cured? We know many patients survived because some of the trephined skulls show signs of healing. One poor fellow, for example, was found to have five holes, but only the last scar showed any signs of infection.
MUMMIES WEREN’T TOO BRIGHT Though early humans apparently saw the need and benefit to opening up the heads of sick people, they did not give much thought to the importance of the brain. The ancient Egyptians, for example, gave it no respect at all.
The Egyptians believed in immortality; they thought the soul would return to the body after death to continue its early life. To prepare for this rebirth, the Egyptians would preserve dead bodies and the deceased’s possessions. Starting about 3500 B.C.E., they began to embalm their dead, removing the major organs and placing them in jars before wrapping the body in linen bandages. Two organs were not treated this way: The heart was left in the body and often protected by an amulet because it was believed to be the center of a person’s being and intelligence; the brain, which was thought to have no value, was unceremoniously scooped out through the nose and thrown away.