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ThinksTock, CtY neuroscience A Journey into the nervous system L by Carli Huber ast January, for the fifth consecutive winter, I pored over a CTY course catalog to find my next summer class. I knew I wanted to continue my pursuit of biology and chemistry, but I had discovered some things about myself over the years. For example, I realized that I don’t enjoy studying large-scale biology, such as entire ecosystems. Instead, I’m drawn to the microscopic world of biology, where the chemistry involved is especially complex. And in addition to the natural sciences, I had developed an interest in psychology. As I looked through the catalog, I was excited to see a course that combined all my interests: Neuroscience. Molecular Foundations In June, I arrived at Dickinson College in Carlisle, Pennsylvania, ready for my latest CTY session. As usual, the dorms, activities, and meals were fantastic, but neuroscience was my focus, and I was instantly obsessed. Neuroscience can be studied at the molecular level, at the cellular level, in the structure of the brain as a whole, and from a psychological perspective. I soon discovered that understanding neuroscience at any level required explicit knowledge of the molecular chemistry involved. 12 imagine I learned that nerve cells, or neurons, communicate with one another by a complex process that involves both electrical and chemical signals. Neurons are known as “excitable” cells because when they are stimulated (chemically, electrically, or mechanically), they generate an electrical impulse that spreads throughout the entire cell. When the impulse reaches the end of the cell, it causes the cell to release a chemical called a neurotransmitter, which can chemically excite nearby neurons. The neurotransmitter released by one neuron can trigger an impulse in the sept/oct 2012 ThinksTock, next. Then, like falling dominoes, a series of impulses travels from one neuron to the next, sending a signal from one part of the nervous system to another. I was fascinated by the combination of physics, chemistry, and biology that makes possible our thoughts, sensations, and actions. branching out Each day, we would dissect sheep brains, learning the functions of nerves and various parts of the brain. I enjoyed slicing the brains at different angles, which gave me several perspectives of a single structure. The hands-on experience also allowed me to observe things I had at first only read about. My personal favorites were the corpora quadrigemina: four mini lobes—one pair for ocular stimuli, one for auditory—in the midbrain that allow a person to react quickly in hazardous situations without conscious thought. We studied the functions of the many lobes, stems, and nerves in part by learning how the body functions without them. I was intrigued by the case of Phineas Gage, a man who was injured in an explosion that drove a large iron pole through his head, damaging the forward portion of his frontal lobe. Gage survived the accident, although changes to his personality caused his friends to describe him as “no longer Gage.” He was impulsive, uninhibited, and prone to speaking “in the grossest profanity.” His was the first case to show a connection between the frontal cortex and personality. Next we examined the sense organs, including the eyes, nose, tongue, and ears, and then moved on to study diseases and conditions of the nervous system. Problems in the nervous system are extremely variable, and can affect nerves, the brain, or both; many are without cures. For one project, each student spent a few days studying a single disease in depth and then presented their topic to the class. I chose Huntington’s disease, a devastating genetic disorder in which nerve cells in the brain waste away. The age of onset depends on how many times the gene has been passed down in a family; the more times the gene is passed down, the earlier the age at which symptoms appear. As cells in the brain begin to deteriorate, people with Huntington’s disease experience hallucinations and problems with memory, speech, movement, and coordination. As is the case with many other diseases of the nervous system, there is currently no cure, only medications to manage symptoms. Through this project, we all came to understand the urgency that fuels neuroscience research. Mind & brain After studying the physical aspects of neuroscience, we delved into some of the mental aspects: consciousness, instincts, emotions, intelligence, depression and euphoria caused by endorphins, and the effects of drugs. Endorphins were a main connection between the physical and mental approaches, and we examined how deficiencies or excesses of this or other neurotransmitters result in conditions such as depression, schizophrenia, and anxiety. Along with learning the basics of neuroscience in class and labs, we read dozens of articles on a range of psychological and physical subjects related to the nervous system. Some of my favorites included an examination of synesthesia, a condition where a person’s senses blend together (for example, a person might perceive letters or numbers as having colors); a report on the impact of Wernicke’s or Broca’s aphasia (problems with comprehension of words and problems connecting ideas to words, respectively) on deaf people who use sign language to communicate; and a comparison of male and female brains, which differ quite a bit in size, amount of white and gray matter, and volume of certain lobes, to name just a few differences. I will admit that taking this course injured my ego a bit: the material was challenging enough that this straight-A honor student failed two quizzes. But I loved what I was learning; I have continued to explore neuroscience topics since the course ended, and I am even considering neuroscience as a college major. The molecular chemistry and biology definitely improved my understanding of the human body, but I think the most valuable thing I learned was how much I have yet to learn. Carli Huber is a junior at Avon Grove high school in Pennsylvania, where she is a member of the cross country team, the national honor society, and the academic competition team. in her free time, carli enjoys skiing, snowboarding, reading, and painting. she plans to major in chemistry, neuroscience, or chemical engineering in college. Learn more about CTY Neuroscience and other summer courses at cty.jhu.edu/summer. www.cty.jhu.edu/imagine imagine 13