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107 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Lower Brain
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Primitive / Reptilian Brain
Limbic system |
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Primitive / Reptilian Brain
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• Vital functions for survival
Breathing Swallowing Etc. |
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Limbic System
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• Emotions
• Fight or flight • Anger, fear |
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Higher Brains
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Cerebrum
Cerebral Cortex |
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Cerebrum
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Wrinkled part
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Cerebral Cortex
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• Surface
• Language • Planning • Thinking • Memory • Organization • Recognition (through any sense) |
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Aristotle
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Cardiocentric
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Aristotle (Cardiocentric)
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o Believed that the heart was the most important part of the body
o Center of intellectual and perceptual functions o Seat of everything important in a man o Brain too far away from the center of the body to be important o Brain + lungs used only to cool the heart |
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Hippocrates
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• Hippocrates was the first to recognize that head injury on one side caused paralysis on the opposite side.
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Galen
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• Agreed that brain was important for intelligence. Keep the four humors in balance.
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Four humors
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four liquids that run through your body. Keep them balanced and you’ll stay healthy.
As long as these are all in balance, you’ll be fine. Too much / too little = throw your body off, go to doctor and he’ll put them back into balance. |
• Blood
• Yellow bile • Black bile • Phlegm |
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Hippocrates + Galen: Brain surgery is fun!
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• Not afraid to cut open the skull and examine the brain during an autopsy. (Others thought the face area was sacred.)
• Used sophisticated tools (for the time). |
very fine points for drilling holes into people’s heads. Probably to release fluid and pressure. Putting the humors back into alignment; balancing everything out.
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Neurons
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Cell body
Axon Dendrites Myelin sheath |
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Cell body
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• This main part has all of the necessary components of the cell, such as the nucleus (contains DNA), endoplasmic reticulum and ribosomes (for building proteins) and mitochondria (for making energy). If the cell body dies, the neuron dies.
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Axon
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• This long, cable-like projection of the cell carries the electrochemical message (nerve impulse or action potential) along the length of the cell.
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Dendrites
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These small, branch-like projections of the cell make connections to other cells and allow the neuron to talk with other cells or perceive the environment. Dendrites can be located on one or both ends of the cell
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Myelin sheath
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• Depending upon the type of neuron, axons can be covered with a thin layer of myelin, like an insulated electrical wire. Myelin is made of fat, and it helps to speed transmission of a nerve impulse down a long axon. Myelinated neurons are typically found in the peripheral nerves (sensory and motor neurons), while non-myelinated neurons are found in the brain and spinal cord.
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Composition of the head
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Skull → CSF → meninges → brain
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o Meninges (the three layers and their functions)
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Dura mater
Arachnoid Pia mater |
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CSF (cerebrospinal fluid)
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• Clear, salty (ew) liquid that your brain floats in
• Circulates constantly • Brain weighs 3 pounds w/o CSF. W/ CSF, 0.5 pounds. Without CSF, 3-pound brain would scrape along the skull and you’d be severely brain damaged. |
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Dura mater (one tough mother)
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Tough and fibrous
Provides protection and support Brain is completely encased in a weird, gross sac Subdural hematoma – bleeding below the dura |
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Arachnoid
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Transparent thin layer
Holds in CSF |
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Pia mater (tender mother)
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Adheres to the brain like really, really tight vacuum wrap
Delicate and highly vascular (supplies blood) Supplies blood to brain tissue Fits inside all the nooks and crannies of the brain |
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Meningitis
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• Swelling of the meninges
• Viral • Bacterial |
• Bacterial
Most serious and deadly Death or severe brain damage |
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Four lobes of cerebral cortex
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• Occipital
• Temporal • Parietal |
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Causes of brain damage
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Infectious diseases (Herpes Simplex Encephalitis)
Cerebrovascular Accident (CVA) Cerebral Hemorrhage (and aneurysms) Ischemic Stroke Thrombotic Stroke Embolic Stroke Traumatic Brain Injury |
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Traumatic brain injury
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Closed head injuries
Open head injuries |
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Neuroimaging techniques
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Structural imagery
Direct measurement of brain activity Indirect measurement of brain activity Functional near-infrared imaging |
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Lateralization
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• Either the right or left hemisphere is more active in certain tasks.
o The left hemisphere controls the majority of functions on the right side of the body, while the right hemisphere controls most of functions on the left side of the body The crossing of nerve fibers takes place in the brain stem. Thus, injury to the left cerebral hemisphere produces sensory and motor deficits on the right side, and vice versa. o One hemisphere has a slightly more developed, or dominant, area in which written and spoken language is organized. Over 95% of right handed people and even the majority of left handed people have dominance for speech and language in the left hemisphere |
o Lefty → RH motor control / Righty → LH motor control
o RH → left field of vision (NOT the left eye, but the left half of the visual field in both eyes) LH → right field of vision |
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Localization of function
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o Behavior and thought processes are localized to certain brain parts
o Brain is not like the liver (the whole thing isn’t the same) o Part of brain responsible for language, for math, for ability to empathize. Localizing specific mental abilities to a specific part of the brain. o Brain areas grow or shrink with usage |
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Franz Gall
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o Most ideas about the brain came from the crude brain surgeries that were made before him.
o Proposed that you can tell a lot about somebody’s brain without having to open up their skull. o Brain surgery is overrated! o Behavior and thought processes are localized to certain brain parts. o Brain is not like the liver. o Part of brain responsible for language, for math, for ability to empathize. Localizing specific mental abilities to a specific part of the brain. o Brain areas grow or shrink with usage. |
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Phrenology
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o Different parts of brain responsible for different mental functions.
o Brain is like a muscle. More you use it, bigger it’ll get. Use it or lose it. o Skull grows over these bumps and valleys. o If you feel someone’s head, you can feel bumps and valleys and you will be able to tell something about that person. If there’s a bump = really use the area. Dent = not using it. o Used the psychograph! – designed to “read” the bumps and dents on your skull. (1930s) o Mark Twain debunked this theory by making a phrenologist look like an idiot. (Samuel Clemens = not funny, Mark Twain = funniest person ever) |
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10% of the brain myth
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o William James: "the average person rarely achieves but a small portion of his or her potential"
o In addition to those 100 billion neurons, the brain is also full of other types of cells that are continually in use. o We can become disabled from damage to just small areas of the brain depending on where it's located, so there's no way that we could function with only 10 percent of our brain in use. o Brain scans have shown that no matter what we're doing, our brains are always active o Unless we have brain damage, there is no one part of the brain that is absolutely not functioning o i.e., If you're sitting at a table and eating a sandwich, you're not actively using your feet. You're concentrating on bringing the sandwich to your mouth, chewing and swallowing it. But that doesn't mean that your feet aren't working -- there's still activity in them, such as blood flow, even when you're not actually moving them. |
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Myths about the brain
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i. You only use 10% of your brain
ii. Alcohol kills brain cells iii. You can get holes in your brain through drug use iv. Brain damage is always permanent v. Your brain stays active after you’ve been decapitated vi. The human brain is the biggest brain vii. You can learn through subliminal messages viii. You get new brain wrinkles when you learn something ix. Listening to Mozart makes you smarter x. Your brain is gray |
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x. Your brain is gray
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o Gray matter exists all throughout the various parts of the brain (as well as in the spinal cord); it consists of different types of cells, such as neurons. However, the brain also contains white matter, which comprises nerve fibers that connect the gray matter.
o The black component is called substantia nigra, which is Latin for (you guessed it) "black substance." It's black because of neuromelanin, a specialized type of the same pigment that colors skin and hair, and it's a part of the basal ganglia. o Finally, we have red -- and that's thanks to the many blood vessels in the brain. So why are preserved brains chalky looking and dull instead of spongy and colorful? It's due to the fixatives, such as formaldehyde, that keep the brain preserved. |
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ix. Listening to Mozart makes you smarter
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o In the 1990s, 36 students in a study at the University of California at Irvine listened to 10 minutes of a Mozart sonata before taking an IQ test. According to Dr. Gordon Shaw, the psychologist in charge of the study, the students' IQ scores went up by about 8 points. The "Mozart effect" was born.
o However, the original University of California at Irvine study has been controversial in the scientific community. Dr. Frances Rauscher, a researcher involved in the study, stated that they never claimed it actually made anyone smarter; it just increased performance on certain spatial-temporal tasks. Other scientists have been unable to replicate the original results, and there is currently no scientific information to prove that listening to Mozart, or any other classical music, actually makes anyone smarter. |
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viii. You get new brain wrinkles when you learn something
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o The ridges are called gyri and the crevices are called sulci. Several of these ridges and crevices even have names, and there are variations in exactly how they look from person to person.
o We don't start out with wrinkly brains, however; a fetus early in its development has a very smooth little brain. As the fetus grows, its neurons also grow and migrate to different areas of the brain, creating the sulci and gyri. By the time it reaches 40 weeks, its brain is as wrinkled as yours is (albeit smaller, of course). So we don't develop new wrinkles as we learn. The wrinkles we're born with are the wrinkles we have for life, assuming that our brains remain healthy. o Our brains do change when we learn -- it's just not in the form of additional sulci and gyri. This phenomenon is known as brain plasticity. By studying changes in the brains of animals like rats as they learn tasks, researchers have discovered that synapses (the connections between neurons) and the blood cells that support neurons grow and increase in number. Some believe that we get new neurons when we make new memories, but this hasn't yet been proven in mammalian brains like ours. |
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vii. You can learn through subliminal messages
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• According to James Vicary, a market researcher, Coke sales in the theater increased by more than 18 percent and popcorn sales by more than 57 percent, proving that his subliminal messages worked. Books published in the late 1950s and early 1970s outlined how advertisers could use techniques like Vicary's to convince consumers to buy their products. Some radio and TV commercials included subliminal messages, but many networks and professional associations banned them. In 1974, the FCC banned the use of subliminal advertising.
• But did the messages work? Turns out, Vicary actually lied about the results of his study. Subsequent studies, including one which flashed the message "Call now" during a broadcast on a Canadian TV station, had no effect on viewers. The infamous 1990s Judas Priest trial, in which the families of two boys who committed suicide claimed that a song told the boys to do it, ended with the judge stating that there was no scientific evidence in their favor. Yet some people still claim that music, as well as advertisements, contains hidden messages. |
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vi. The human brain is the biggest brain
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• The average adult human brain weighs about 3 pounds (1,361 grams). The dolphin -- a very intelligent animal -- also has a brain that weighs about 3 pounds on average. But a sperm whale, not generally considered to be as intelligent as a dolphin, has a brain that weighs about 17 pounds (7,800 grams). On the small end of the scale, a beagle's brain is about 2.5 ounces (72 grams), and an orangutan's brain is about 13 ounces (370 grams). Both dogs and orangutans are pretty smart animals, but they have small brains. A bird like a sparrow has a brain that weighs less than half an ounce (1 gram).
• You may notice something important in all of those comparisons. An average dolphin's body weighs about 350 pounds (158.8 kilograms), while a sperm whale can weigh as much as 13 tons. In general, the larger the animal, the larger the skull, and therefore, the larger the brain. Beagles are fairly small dogs, at about 25 pounds (11.3 kg) maximum, so it stands to reason that their brains would also be smaller. The relationship between brain size and intelligence isn't really about the actual weight of the brain; it's about the ratio of brain weight to the entire body weight. For humans, that ratio is about 1-to-50. For most other mammals, it's 1-to-180, and for birds, it's 1-to-220. The brain takes up more weight in a human than it does in other animals. • Intelligence also has to do with the different components of the brain. Mammals have very large cerebral cortexes, unlike birds, fish or reptiles. The cerebellum in mammals houses the cerebral hemispheres, which are responsible for higher functions like memory, communication and thinking. Humans have the largest cerebral cortex of all mammals, relative to the size of their brains. |
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v. Your brain stays active after you’ve been decapitated
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• This concept perhaps first appeared during the French Revolution, the very time period in which the guillotine was created. On July 17, 1793, a woman named Charlotte Corday was executed by guillotine for the assassination of Jean-Paul Marat, a radical journalist, politician and revolutionary. Marat was well-liked for his ideas and the mob awaiting the guillotine was eager to see Corday pay. After the blade dropped and Corday's head fell, one of the executioner's assistants picked it up and slapped its cheek. According to witnesses, Corday's eyes turned to look at the man and her face changed to an expression of indignation. Following this incident, people executed by guillotine during the Revolution were asked to blink afterward, and witnesses claim that the blinking occurred for up to 30 seconds.
• These stories seem to give credence to the idea that it's possible for someone to remain conscious, even for just a few seconds, after being beheaded. However, most modern physicians believe that the reactions described above are actually reflexive twitching of muscles, rather than conscious, deliberate movement. Cut off from the heart (and therefore, from oxygen), the brain immediately goes into a coma and begins to die. According to Dr. Harold Hillman, consciousness is "probably lost within 2-3 seconds, due to a rapid fall of intracranial perfusion of blood" [source: New Scientist]. • So while it's not entirely impossible for someone to still be conscious after being decapitated, it's not likely. Hillman also goes on to point out that the so-called painless guillotine is likely anything but. He states that "death occurs due to separation of the brain and spinal cord, after transection of the surrounding tissues. This must cause acute and possibly severe pain." This is one of the reasons why the guillotine, and beheading in general, is no longer an accepted method of execution in many countries with capital punishment. |
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iv. Brain damage is always permanent
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• To many people, the mere idea of brain damage conjures images of people in persistent vegetative states, or at the very least, permanent physical or mental disability.
• But that's not always the case. There are many different types of brain damage, and exactly how it will affect someone depends largely on its location and how severe it is. A mild brain injury, such as a concussion, usually occurs when the brain bounces around inside the skull, resulting in bleeding and tearing. The brain can recover from minor injuries remarkably well; the vast majority of people who experience a mild brain injury don't experience permanent disability. • On the other end of the spectrum, a severe brain injury means that the brain has suffered extensive damage. It sometimes requires surgery to remove built-up blood or relieve pressure. For nearly all patients who live through a severe brain injury, permanent, irreversible damage results. • So what about those in between? Some people with brain damage experience permanent disability but can recover partially from their injury. If neurons are damaged or lost, they can't grow back -- but the synapses, or connections between neurons, can. Essentially, the brain creates new pathways between neurons. In addition, areas of the brain not originally associated with some functions can take over and allow the patient to relearn how to do things. Remember the phenomenon of brain plasticity mentioned in the myth about brain wrinkles? That's how stroke patients, for example, can regain speech and motor skills through therapy. • The important thing to remember is that there are still a lot of unknowns about the brain. When a person is diagnosed with a brain injury, it's not always possible for doctors to know exactly how well someone will be able to recover from the damage. Patients surprise doctors all the time and exceed expectations of what they're able to do days, months and even years later. Not all brain damage is permanent. |
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iii. You can get holes in your brain through drug use
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• Some people claim that only the most severe drug use can have any lasting effects, while others believe that the first time you use a drug, you're causing long-term damage. One recent study states that using drugs like marijuana only cause minor memory loss, while another claims that heavy marijuana use can permanently shrink parts of your brain. When it comes to using drugs like cocaine or Ecstasy, some people even believe that you can actually get holes in your brain.
• In truth, the only thing that can actually put a hole in your brain is physical trauma to it. Researchers do claim that drugs can cause short-term and long-term changes in the brain. For example, drug use can lower the impact of neurotransmitters (chemicals used to communicate signals in the brain) like dopamine, which is why addicts need more and more of the drug to achieve the same feeling. In addition, changes in the levels of neurotransmitters can result in problems with neuron function. Whether this is reversible or not is also up for debate. • On the other hand, a study in New Scientist from August 2008 states that long-term use of some drugs actually causes certain structures in the brain to grow, resulting in a permanent change. They claim that this is which is why it's so difficult to change the behaviors of addicts. • But although the jury's still out on exactly how different drugs can affect your brain for the long term, we can be reasonably sure of one thing: No drug actually puts holes in your brain. |
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ii. Alcohol kills brain cells
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• Alcohol use doesn't actually result in the death of brain cells. It can, however, damage the ends of neurons, which are called dendrites. This results in problems conveying messages between the neurons. The cell itself isn't damaged, but the way that it communicates with others is altered. Mostly reversible.
• Alcoholics can develop Wernicke-Korsakoff syndrome (loss of neurons in some parts of the brain) memory problems, confusion, paralysis of the eyes, lack of muscle coordination and amnesia. It can lead to death. However, the disorder isn't caused by the alcohol itself. It's the result of a deficiency of thiamine, an essential B vitamin. Not only are severe alcoholics often malnourished, extreme alcohol consumption can interfere with the body's absorption of thiamine. |
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i. You only use 10% of your brain
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o William James: "the average person rarely achieves but a small portion of his or her potential"
o In addition to those 100 billion neurons, the brain is also full of other types of cells that are continually in use. o We can become disabled from damage to just small areas of the brain depending on where it's located, so there's no way that we could function with only 10 percent of our brain in use. o Brain scans have shown that no matter what we're doing, our brains are always active o Unless we have brain damage, there is no one part of the brain that is absolutely not functioning o i.e., If you're sitting at a table and eating a sandwich, you're not actively using your feet. You're concentrating on bringing the sandwich to your mouth, chewing and swallowing it. But that doesn't mean that your feet aren't working -- there's still activity in them, such as blood flow, even when you're not actually moving them. |
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Synapses
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o Each neuron is connected to other neurons through about 10000 synapses. So there are about 1,000,000,000,000,000 synapses.
o Synapse is where communication takes place • Neurons communicate through an electro-chemical process • Neurotransmitters are released from the buttons, pass through the synapse and tell the next neuron to fire or not to fire. |
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Neurotransmitters
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o Neurotransmitters are passed through the synaptic gap.
o Neurotransmitters: • Acetylcholine (Ach) down in Alzheimer’s • Dopamine (DA) down in Parkinson’s • Serotonin down in depression, OCD |
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Synaptic plasticity
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o Active synapses become stronger as we learn, feel, experience, etc.
o Long-term potentiation (LTP) o The neural basis for learning and memory o Inactive synapses may weaken or be “pruned” |
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Long-term potentiation
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o Neural connections that are used more often become stronger / faster. Basis for learning & memory. If you have neural pathways that are activated over an over again, they become easier to use (erosion in rock from water). Not used, you may lose connections.
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Pruning peaks
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o “Pruning peaks” ~ 3 years old, adolescence
o “Overpruning” – could it cause Schizophrenia? o Disconnect between essential neurons. Onset Schizophrenia is early adolescence. o “Underpruning” – could it cause Autism? • Sensory overload. |
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Dendritic growth
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o More dendrites → more synapses → more learning
o In children, dendritic growth is explosive. o Is there dendritic growth in adults? – Yes, there is supporting evidence. |
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Neurogenesis
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o Making new neurons
o It was previously thought that adult brains could not create new neurons. However, now there is evidence of neurogenesis, specifically in the areas important for memory. o However (again), we don’t know how well new neurons function. After all, these are neurons that are grown by our old, tired brain, not by our young, active brains. Maybe if they’re produced after the fact, we don’t know if the new neurons will improve memory |
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Chemical vs. Electrical Communication
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o For neurons, communications begin inside of the neuron as electrical then are changed to chemical as they transfer signals and such through the body
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Glial cells
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Astrocytes
Microglia Oligodendrocytes |
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Astrocytes
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• Hold neurons in place. Literally supporting them.
• Regulate neurotransmitters. • Form / break neural connections. (Surprising how active they are.) |
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Microglia
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• “eat” dead neurons (Zombieglia?)
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Oligodendrocytes
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• Myelin maker!
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Brain structures
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Brain stem
Limbic system Cerebellum Cerebrum |
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Brain stem
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Under limbic system
Vital life functions • Breathing • Heart beat • Blood pressure • Wakefulness • Arousal • Attention “Simplest” part of brain – all animals have it. Some have brains that look like only the brain stem. |
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Limbic system
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“Emotional brain”
Buried in cerebrum Old like cerebellum Contains: • Thalamus • Hypothalamus • Amygdala • Hippocampus |
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Cerebellum
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“Little brain”
Similar to cerebrum with two hemispheres, highly folded surface Regulation of coordination and movement, posture, balance Assumed to be older than cerebrum (evolutionally) |
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Cerebrum
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Largest part of the brain
Associated with higher brain function such as thought and action Divided into four lobes • Frontal • Parietal • Occipital • Temporal Highly wrinkled. More efficient Two hemispheres (R + L … Remus Lupin!) Mostly symmetrical, but each side functions slightly differently from the other Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body Intellectual function, speech, emotion, integration of sensory stimuli of all types, initiation of the final common pathways for movement, and fine control of movement. |
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Corpus callosum
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Connective bundle of axons between two hemispheres of brain
Allow brain halves to communicate with each other |
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Four lobes of cerebral cortex
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Frontal
Parietal Occipital Temporal |
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Frontal
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(front of the brain)
• Reasoning • Planning • Parts of speech • Movement • Emotions • Problem solving |
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Parietal
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(top of the brain, between frontal and occipital)
• Movement • Orientation • Recognition • Perception of stimuli |
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Temporal
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(sides of the brain)
• Perception and recognition of auditory stimuli, memory, speech |
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Occipital
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(back of the brain)
• Visual processing |
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Anterior
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towards the front
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Posterior
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towards the back
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Inferior / ventral
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"lower"
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Superior / dorsal
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Upper
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Medial
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towards the middle
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Blood brain barrier (BBB)
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o Blood vessels in the brain have extra protection
o Blood vessel “bouncer” – toxins are left out o Endothelial cells are packed tightly around the vessel o Only certain molecules can pass through (oxygen, glucose) o Drug treatments are often hindered because they can’t penetrate the BBB |
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Lateral
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Outside
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Glial cells
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• There are 10 times more glial cells than neurons in the brain
• Until 1995, glia were thought to just support neurons by supplying nutrition and protection. Seen as very passive. Associated with brain function, but very boring when the common assumption is that they just support the neurons. |
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Cerebral cortex (gray matter) vs. Subcortical areas (white matter)
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Cerebral cortex
• Surface of the cerebrum is called the cerebral cortex • Made up of brain cell bodies • Referred to as “gray matter” Subcortical areas • Are made up of axons and their myelin sheath • White matter • Connective areas |
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Infectious diseases (Herpes Simplex Encephalitis)
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o 70% die without treatment
o 25% die with treatment o 50% of survivors have fairly severe impairments o MOST people have been infected with HSV-1. o FEW have been infected with HSE. |
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Diseases
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o Alzheimer’s
o Huntington’s o Parkinson’s |
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Cerebrovascular Accident (CVA)
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o a stroke
o Disrupted blood flow to the brain o Comprises 70% of all neuropathology o Almost 90% of patients will have lasting deficits o Very mild to very severe o Depends on location of stroke and where damage is |
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Cerebral Hemorrhage (and aneurysms)
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o A cerebral vessel breaks
o Blood flow is interrupted o Damage will occur in all places where that blood vessel was supposed to be supplying blood. o Blood flooding that area poisons neurons. o Hemorrhages can result from an aneurysm bursting |
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Ischemic stroke
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o A cerebral artery to the brain is blocked.
o 80% of all strokes |
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Thrombotic Stroke
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o A close forms in a blood vessel.
o Symptoms are often gradual and diffuse |
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Embolic stroke
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o A traveling clot (e.g. fat, air) lodges in a vessel.
o Pieces of plaque can break free, travel to the brain and block blood vessels that supply blood to the brain. o Sudden and dramatic symptoms. o One side of body suddenly stops working o Speech becomes slurred |
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Traumatic Brain Injury
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o High Risk Groups
o Males: 15 – 24 years o Substance abusers o Infants (64% abuse) o The Elderly o Those who had a prior brain injury Closed Open |
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Closed head injuries
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• Closed head injuries
The skull remains intact Swelling brain tissues compress against the skull • Coup and Contrecoup injuries • Angular acceleration • Diffuse axonal shearing injury (DAI) • Acceleration-deceleration trauma (and frontal lobe scraping) |
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Open head injuries
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The skull is fractured and the dura is breached.
Most people with open head injuries die. Some don’t, but most have deficits …but then there’s Phineas Gage |
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• Coup and Contrecoup injuries
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o Coup – damage at the site of impact
o Contrecoup – Due to the brain hitting the skull o Occurs on opposite side of the coup injury |
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• Angular acceleration
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o Head rotates violently
o Neck stop head, brain keeps twisting |
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• Diffuse axonal shearing injury (DAI)
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o Axons are stretched / torn
o Usually result in global deficits |
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• Acceleration-deceleration trauma (and frontal lobe scraping)
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o Shaken baby syndrome
o Damage can occur from the brain scraping the bony ridges of the skull. |
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Phineas Gage’s story
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o Famous Open Head Injury Case
o 1800s o A railroad foreman who forgot the sand at a bad moment… o …a tamping iron went through his head o The TBI caused personality and emotional changes. o More prone to outbursts, impulsive behavior, lost his job because he kept yelling at people. o Got a job with the circus telling this story. |
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Modular/localist approach (assumptions, evidence supporting)
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o Assumptions
• Brain areas are highly specialized for specific mental abilities. • Through careful study, we will eventually be able to make a detailed “brain map” of mental processes. • A lot of researches in neuro-imaging who believe that this could potentially be completed within our lifetime. Legitimate brain map. |
o Evidence supporting
• We have found some strong relationships between specific brain areas and resulting deficits (problems). • Ex: Left hemisphere damage usually results in language deficits. • Neuro-imaging researches show evidence that cognitive processes can be localized to specific areas. |
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Interactive approach (assumptions, evidence supporting)
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• Mental processes involve interaction among many brain areas.
• These areas are so closely interconnected that a process cannot be localized to just one area. • A scan of an active area (FMRI) subtracts a “nothing” scan, highlighting the hard-working areas. But this could be subtracting areas that are actually active in the process, but not AS active as the bright part of an FMRI. |
o Evidence supporting
• Brain cells (neurons) are densely interconnected and interactive. • After brain damage, brain pathways can change and people may recover functions. • “Neural plasticity” • Having an interactive brain means that you have the potential to remap the processes. |
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Computed Tomography (how does it work?)
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• x-rays are taken at different angles, then sent to a computer
• A thin x-ray beam rotates around an area of the body |
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CT (pros and cons)
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• Pros
Fast, painless, low cost • Cons radiation exposure, low resolution |
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Magnetic Resonance Imaging (How does it work?)
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• The brain is placed in the field of a strong magnet
• Shortwave radio frequency pulses are applied • Resonance signals are measured • *movement of protons measured |
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MRI (pros and cons)
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• Pros
safer (no radiation), better resolution • Cons higher cost, claustrophobic/noisy/slow, no metal allowed |
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o Electroencephalogram EEG (How does it work?)
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• Electrodes pick up electrical discharges from neurons
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EEG (pros and cons)
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• Pros
excellent times, resolution (<5ms), not invasice, easy, inexpensive (people/babies/animals) • Cons poor spatial resolution (“skull smearing”), can’t measure activity of deeper (subcortical) structures |
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o Magnetoencephalogram MEG (How does it work?)
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• Measures the tiny magnetic fields produced by neurons
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MEG (pros and cons)
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• Pros
excellent time resolution (<5ms), not invasive (anyone can do it) • Cons spatial resolution is not precise, info about deeper (sub cortical) structures is less reliable (too much travel) |
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o *Positron Emission Tomography PET (How does it work?)
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o Measures blood flow correlated with mental activities
o Radioactive glucose is introduced into blood MORE RADIOACTIVITY → MORE GLUCOSE UPTAKE → MORE ACTIVITY |
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PET (pros and cons)
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o Pros
• Better Spatial resolutions, can measure deeper structures • good for Alzheimer’s Cons • radiation exposure (although tiny), expensive (few machines), poor time resolution (45 seconds)/better for profiling, ie Alzheimer’s vs. normal brain |
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Functional Magnetic Resonance Imaging (How does it work?)
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• Uses magnetic properties of hemoglobin (oxygen carrier)
• Blood-oxygen-level dependent (BOLD) signal |
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fMRI (pros and cons)
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• Pros
No radiation involved Very good spatial resolution (w/ MRI) Can measure deeper structures • Cons Only OK temporal resolution (~500 ms) • higher cost, claustrophobic/noisy/slow, no metal allowed |
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Functional near-infrared imaging (How does it work?)
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o Uses infrared light to measure deoxy hemoglobin
o Active regions of the brain reflect less light o No magnet, no radiation. Just shining lights, get to sit up, move around, move their head. |
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fNIR (pros and cons)
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• pros of fMRI, plus:
• cheaper and easier • no limitation on patients (no radiation, no tube, etc.) |
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