47 pages • 1 hour read
The Tell-Tale Brain
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Introduction-Chapter 1Chapter Summaries & Analyses
Introduction Summary: “No Mere Ape”
In the Introduction, Ramachandran explores the modern history of perspectives on human uniqueness. He starts this journey with intellectuals roughly spanning the Victorian and Edwardian eras (1815-1914), including Charles Darwin, Thomas Huxley, and Richard Owen. These intellectuals debated whether humans were truly unique compared with other primates.
Darwin was the first to propose that humans and apes had a common ancestor. He also believed that human mental abilities evolved from the same kind of traits seen in other apes. Owen, who founded the science of comparative anatomy, believed humans were unique. He disagreed with Darwin, pointing out the large gap between the mental abilities of humans and apes. Owen believed humans had a unique anatomical structure called the hippocampus minor. Huxley, who was a friend of Darwin, vehemently argued against Owen’s theory.
Modern studies of the human brain disprove Owen’s hippocampus minor theory. However, Ramachandran believes he was right to suggest the human brain is “something unique, something unprecedented, something transcendent” (4). In contrast to apes, humans write, create, investigate, and self-reflect. Self-reflection is especially important to Ramachandran and represents the greatest mystery of all.
Ramachandran suggests that our hominin ancestors provide clues to human uniqueness. As one example, Neanderthals were close to achieving human uniqueness. Neanderthals are traditionally depicted as slow-witted, brutish cave dwellers without language. However, this is far from true. Like humans, Neanderthals buried their dead, made art and jewelry, and likely had language capabilities (although probably not as sophisticated as humans). The reasons behind the Neanderthals’ disappearance around 30,000 years ago remain a mystery. Researchers postulate that modern humans outcompeted or even killed-off Neanderthals. Ramachandran believes Neanderthal genes are the key to understanding what happened to them, as well as the fine line that divided them and modern humans.
Ramachandran next turns to providing a quick primer on human brain anatomy. Billions of nerve cells or neurons comprise the brain. Neurons transmit information to one another through fibers (dendrites) and cables (axons). Synapses are the points of contact where neurons share information. There are nearly 100 structures in the brain. These structures are made from networks of neurons that control discrete cognitive or physiological functions. Damage to these different structures causes neurological disorders.
Chapter 1 Summary: “Phantom Limbs and Plastic Brains”
In this chapter, Ramachandran uses his early work with phantom limbs to show the human brain’s incredible capacity to rewire and adapt to changing circumstances, which is known as neuroplasticity. This work reveals that our unique brain plasticity shaped human evolution and cultural development.
A phantom limb occurs when a patient still feels sensation where a limb has been amputated. Ramachandran describes patients, such as Victor, who feel sensation in their phantom limb when their face is touched with a Q-tip, knee hammer, and water. Ramachandran discovered that sensations throughout the body are mapped onto a strip of cortex called the postcentral gyrus. The map is mostly anatomically accurate, with one exception: The map of the face is located next to the map of the arm. This anomaly explains the phantom limb phenomenon. Even after amputation, the arm remains present in the brain map. The brain still fires sensory signals to the arm even though there is now a dead connection. Thus, when a person touches their face, the facial nerves fire a signal to the now phantom limb. This discovery shows the unique plasticity of the human brain.
Ramachandran moves to describing how this dead connection or neurological issue impacts patients. For example, some patients report feeling paralysis in their phantom limb. Ramachandran hypothesized that the brain learned this state of paralysis. Prior to amputation, patients often have paralysis in the limb. When the motor cortex in the brain sends a movement command to the limb, the sensory cortex receives negative feedback from the eyes, joints, skin, and muscle since the limb cannot move. This negative feedback loop becomes part of the brain circuitry. When the limb is amputated, this circuitry or feeling of paralysis carries over to the phantom limb.
Ramachandran tests this hypothesis using a mirror box. This tool tricks the human brain into seeing the phantom limb, which repairs the movement-visual feedback loop in the brain circuitry, a method called mirror visual feedback (MVF). MVF enables patients to unlearn the paralysis sensation in their phantom limb. This discovery shows that perception is reality in the human brain. Ramachandran suggests MVF might be extended to non-phantom limbs, even alleviating learned pain in a rare pain disorder called complex regional pain syndrome-Type II (CRPS-II).
Introduction-Chapter 1 Analysis
In the opening section, Ramachandran lays out his approach to science. To understand The Nature of Human Uniqueness and the human brain, Ramachandran studies patients with neurological disorders that result in unusual mental experiences or perceptions. Ramachandran was one of the first neuroscientists to systematically study these disorders. Conventional wisdom held that patients exaggerated or made up these disorders. Ramachandran has shown that most of these neurological disorders are real. He also uses simple studies and technology, rather than more costly technology, in his lab to understand why these symptoms occur. Ramachandran’s work provides insights into the structure and functions of the healthy, normal brain. Ramachandran also emphasizes that his approach to science is question-driven rather than methodology-driven. Readers clearly see this throughout the book, since Ramachandran continuously poses various questions rather than discussing methodologies at length.
Ramachandran also shows the power of simple, low-cost experiments and technologies to uncover mysteries about the human brain. His experiments with patients suffering from phantom limbs involved household items (e.g., Q-tips, water, and mirrors). Despite the mundaneness of these items, Ramachandran made several major discoveries which radically changed how doctors helped patients with phantom limbs. His approach helps readers see how important it is to have a diversity of techniques and processes in science.
The topics discussed throughout the book are complex, but Ramachandran makes them accessible by employing numerous elements of popular science writing (See: Background). As one example, he routinely includes photos and figures that help explain a complex subject. In Chapter 1, Figures 1.1 and 1.2 help illuminate the brain map concept. The former shows which parts of the face when touched evoke a sensation in different parts of the phantom limb. The latter enables readers to visually understand the proximity between the brain’s map of the face and arm. Sometimes figures and photos can be confusing in non-fiction books, but most of Ramachandran’s examples help amplify his key arguments.
Ramachandran also refutes many dogmas throughout the book. In this section, one example was the belief that the brain was not plastic. Prior to his work with phantom limbs, most scientists believed that the brain’s circuitry did not change after early fetal and childhood development. However, Ramachandran showed that the brain rewired and adapted to changing circumstances. This discovery was a giant leap forward for our understanding of the human brain.
Ramachandran also introduces the three key themes of the book. The Nature of Human Uniqueness represents the first theme. He briefly touches on three parts of the brain only found in humans: Wernicke’s area in the left temporal lobe, inferior parietal lobules (IPL) in each parietal lobe, and the prefrontal cortex. In humans, Wernicke’s area is seven times larger than the same area in chimpanzees. It helps with semantics and meaning comprehension. These two functions are also unique to humans. IPL grew so large during human evolution that they split into two processing regions: angular gyrus and supramarginal gyrus. The two different hemispheres of IPL house truly human traits, including the ability to create a spatial model of the outside world in your mind and to do arithmetic. The prefrontal cortex, also known as “‘the seat of humanity’” (21), orchestrates empathy, foresight, ambition, and more.
The second theme is The Impact of Neurological Disorders. Jimmie, one of Ramachandran’s patients, had a paralyzed phantom limb. He also experienced painful cramping in his phantom limb, which his doctors could not figure out. Jimmie used Ramachandran’s mirror-box set-up, which helped trick his brain into believing his phantom limb was plugged back into the brain circuitry. Using MVF helped Jimmie unlearn his learned paralysis as well as actually exorcise his phantom limb and the cramping; the latter had never been done before. By studying phantom limbs and understanding what was going on in the brain, Ramachandran was able to develop treatments to help alleviate issues associated with this disorder.
Evolution and Brain Development is the final theme. Ramachandran firmly believes that evolution shaped the human brain. One interesting example is the origins of laughter, which Ramachandran believes started as an “‘all’s okay’” (39) response in potentially threatening situations, known as a false alarm theory. By laughing in these situations, the individual is relaying to others that the situation is fine. Resources do not need to be wasted on imaginary danger. A key driver of evolution is reproduction. By having an “all’s okay” response, our hominin ancestors could more easily convey when they were truly in danger. It is important to note that this theory falls under one of Ramachandran’s speculations.
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