By Yvette Leung ’14, thurj Staff
What separates apes from humans? What causes some people to doubt their own existence? Why can some associate colors with numbers while others associate them with musical notes? Dr. Vilyanur S. Ramachandran seeks to probe the inner workings of the human brain in his new book, The Tell-Tale Brain: A Neuroscientist’s Quest for What Makes Us Human.
Ramachandran seeks to answer some of the oldest questions about our existence by posing the following questions to readers: are we merely a more sophisticated form of apes? Though it is true that we are nearly genetically identical to apes, he still contends that we have quite the upper hand over our primate relatives. “An ape can reach for a banana, but only
humans can reach for the stars. Apes live, contend, breed, and die in forests – end of story. Humans write, investigate, create, and quest. We splice genes, split atoms, launch rockets. We peer upward into the heart of the Big Bang and delve deeply into the digits of pi” (4). The real culprit behind our vast advantage, the brain, weighs a mere three pounds and, upon initial inspection, may remind us more of a chunk of jelly than an intricate circuit encoding an infinite amount of intellectual possibilities.
Ramachandran presents a variety of patients with astonishing neurological symptoms, giving us a glimpse into the complexities of the human brain. A woman bursts out in an uncontrollable fit of laughter when poked with a needle. A man feels pain in a phantom arm after amputation. A patient with Capgras syndrome believes that his own mother is an imposter of his “real” mother. A man utterly denies his own existence and adamantly claims that he is a rotting corpse, symptoms of Cotard’s syndrome. A brief overview of the anatomy of the brain segues into a detailed description of these various neurological oddities and potential reasons for why these idiosyncrasies occur. Take, for instance, a woman who could pour a glass of water but not see the water flowing out of it, describing it only as a “stream of water [that] looked like a static icicle” (60). Ramachandran analyzes this condition as a deficit in the medial temporal (MT) area of the brain that is crucial for seeing and detecting movement. Yet this example only demonstrates a simple malfunction in the brain’s wiring. Often, the more complicated symptoms occur when the brain tries to internally compensate for an abnormality in one area by expanding or crossing into another region.
A prime example of the brain trying to offset damage is the different pathways that exist for visual perception. Evolutionarily speaking, the “old” pathway involves an area called the superior colliculus, while the “new” pathway involves the highly developed visual cortex. Ramachandran illuminates these pathways through a fascinating yet counterintuitive phenomenon known as blindsight. A man who has sustained damage to the left visual region of his brain should theoretically be blind in his right visual field since the left side of the brain processes what is seen in the right visual field of the observer. However, when prompted by Ramachandran to touch a certain spot of light to the right, the patient protests but nevertheless miraculously touches the spot precisely on every single try. The results are puzzling, and the explanation may be even more baffling. Although the primary (“new”) pathway involving the visual cortex is damaged, the innate “backup” system (the “old” pathway) that involves the superior colliculus is still functional, which allows the patient to still perceive the stimulus of the light accurately but consciously be unaware of the perception.
Still another dazzling case of the plasticity, or flexibility, of the brain is demonstrated through the condition known as synesthesia. Synesthesia occurs when the senses became tangled in one another, and it often manifests itself in the form of confusion between numbers and colors. Some patients see the number 7 as bright red, while 8 is yellow and 3 is blue. Each number carries its own unique, characteristic color that is readily perceived by the individual whenever they see the number. For others, synesthesia comes in the form of associations between certain notes and colors, as well as textures and emotions. Ramachandran attributes these behavioral anomalies to the cross-wiring of adjacent regions in the brain. The brain region that encodes color, for instance, is coincidentally located close to the area that is responsible for processing numerical data. His suggestion that the neurons in both specialized regions are communicating within these individuals in different ways may eventually enable us to understand the mechanisms in which we ourselves perceive the world around us.
In addition to these intriguing case studies, Ramachandran focuses on specialized brain cells called mirror neurons. He proposes that mirror neurons may be an evolutionary reason for why humans are capable of compassion and empathy, and why other creatures are not. Specifically, these mirror neurons are activated in the brain not only when an action is being performed by the person herself, but also when the person sees others performing that same action. He suggests that mirror neurons may offer a window into the minds of others, allowing us to be able to imitate our peers and to be self-aware.
Ramachandran himself admits that his notions about mirror neurons are often speculative at the very best, but they will only continue to be elucidated as the field of neuroscience develops. His attempt to describe the captivating antics of the brain is more than valiant in The Tell-Tale Brain as he communicates his thoughts in a compelling read. His greatest achievement is the enthusiasm which he imparts about the brain and its seemingly endless neuronal wiring. Readers will be excited to pursue the myriad of unanswered questions in neurobiology, a rapidly expanding field in which new discoveries are made each and every day. As we continue to make leaps of progress in understanding what makes us unique and different, Ramachandran has provided us a guidebook to exploring the human brain as the next frontier of the universe.