BRAIN MENTAL HOSPITAL PHONE MENU • Hello and thank you for calling The State Mental Hospital. Please select from the following options menu: • If you are obsessive-compulsive, press 1 repeatedly. If you are co-dependent, please ask someone to press 2 for you. If you have multiple personalities, press 3, 4, 5 and 6. If you are paranoid, we know who you are and what you want, stay on the line so we can trace your call. If you are delusional, press 7 and your call will be forwarded to the Mother Ship. If you are schizophrenic, listen carefully and a little voice will tell You which number to press. If you are manic-depressive, hang up. It doesn't matter which number you press, nothing will make you happy anyway. If you are dyslexic, press 9-6-9-6. If you are bipolar, please leave a message after the beep or before the beep or after the beep. • But Please wait for the beep. If you have short-term memory loss, press 9. If you have short-term memory loss, press 9. If you have short-term memory loss, press 9. If you have low self-esteem, please hang up. Our operators are too busy to talk with you. If you are menopausal, put the gun down, hang up, turn on the fan, lie down and cry. You won't be crazy forever. THE BRAIN ANATOMICAL REGIONS A. Cerebrum B. Diencephalon Thalamus Hypothalamus C. Brain Stem Midbrain Pons Medulla oblongata D. Cerebellum THE BRAIN FUNCTIONAL REGIONS A. MOTOR AREAS B. SENSORY AREAS C. HIGHER FUNCTIONS • MAJOR ANATOMICAL REGIONS OF THE BRAIN – Cerebrum – Diencephalon – Brain Stem – Cerebellum The Brain Since the brain is so important, it is protected by the skull, cerebrospinal fluid which cushions it, and meninges which are membranes that surround the brain and only let certain substances cross through to the brain. The brain is one of the few organs that can only use glucose to get ATP as its energy source. Therefore, without some sugar in our bloodstream, the brain will die. That’s one reason why proper nutrition is so important. The Brain By the way, geniuses have the same size brain as everyone else; they are just more efficient at forming synapses. They have more dendrites and more synapses. You can develop more dendrites and synapses by keeping your brain active by learning and reading new things. We don’t use 10% of our brains, we use 100%. Fun Fact: -Scientists say the higher your I.Q. The more you dream. CEREBRUM The brain is divided into parts, and is bilaterally symmetrical. In general, the left side controls the right half of the body, and the right side of the brain controls the left half of the body. The largest portion is the CEREBRUM, which makes up 80% of the brain. The cerebrum controls logical thought and conscious awareness of the environment. It is also the area responsible for the highest sensory and motor activity. The cerebrum is made up mostly of grey matter (cell bodies, dendrites, and unmyelinated axons). GYRUS AND SULCUS The surface is not smooth, it’s convoluted. Each bump on the surface of the cerebrum is called a GYRUS, and each shallow groove on the surface of the cerebrum is called a SULCUS. This formation increases the surface area, and the surface is where the information processing is. Figure 13.7a CEREBRUM The cerebrum is divided into 2 halves called CEREBRAL HEMISPHERES, which are separated by the longitudinal fissure. The right cerebral hemisphere controls the activity of, and receives sensory input from the left side of the body. The left cerebral hemisphere controls the activity of, and received sensory input from the right side of the body. Each hemisphere is divided into lobes, named for the bones on top of them. The Cerebral Hemispheres and lobes Figure 13.7b, c The Cerebral Hemispheres and lobes Central sulcus The FRONTAL LOBE and PARIETAL LOBE are separated by the CENTRAL SULCUS. The TEMPORAL LOBE is between the parietal and frontal lobe, separated by the LATERAL SULCUS. The OCCIPITAL LOBE does not have a real border; it’s just a region. These are the anatomical areas, but the functional Lateral sulcus areas are more important. CORPUS CALLOSUM If you slice the brain down the center in a mid- sagittal section, you will slice through a white colored tissue called the CORPUS CALLOSUM, which is the area that connects the right and left halves of the brain. CORPUS CALLOSUM The CORPUS CALLOSUM is the area that connects the right and left halves of the brain. Sheep brain Corpus callosum CORPUS CALLOSUM This is the area that is responsible for the right half of the brain communicating with the left half of the brain. If the corpus callosum was cut, there would be no communication between the right and left halves of the brain. Autism is a neurological disease that includes problems with communication between the right and left cerebral hemispheres. Phineas Gage Phineas was a railroad construction foreman who survived an accident in which a large iron rod was driven completely through his head, severing connections in his left frontal lobe. It changed his personality; he became emotional and had frequent outbursts. This was the first case suggesting that damage to specific regions of the brain might affect personality and behavior. Phineas Gage The left side of the brain is responsible for critical thinking, and the right side is responsible for emotion. Since his left frontal lobe was damaged, his emotions went unchecked. CORPUS CALLOSUM: Fun Fact Women have a wider corpus callosum than men. They tend to use both sides of their brain more than men do. That’s why they like to talk more. Give a little girl a doll, and she will hold it like a baby. Give a little boy a doll, and he will take the head off to see what it looks like inside. This is a difference between using both sides of the brain vs. just one side. Diencephalon Consists of two parts: Thalamus The superior portion of the diencephalon Processes sensory information according to importance Major relay station for sensory impulses to the cerebrum Hypothalamus The inferior portion of the diencephalon Provides homeostatic control over the body (maintains the homeostasis of the body) Controls hunger/thirst body temperature Figure 13.15 THALAMUS The THALAMUS functions to sort out all the sensory information. It compares the input and determines what information is worth sending to the cortex. Your body ignores most sensory information. Up until now, have you noticed the sound of the air conditioner? It’s not important, so it goes unnoticed. This area also compares information from the right and left eyes for stereoscopic vision, and the right and left ear to determine direction of sound. Thalamus Hypothalamus Pituitary gland Thalamus Hypothalamus Pituitary gland HYPOTHALAMUS This small area exerts more control over autonomic functioning than any other part. Provides homeostatic control over the body (maintains the homeostasis of the body) It maintains homeostasis by controlling the autonomic nervous reflexes, glucose and hormone levels. It is also the main visceral control center, so it controls body temperature, hunger and thirst, and blood pressure. The hypothalamus is part of the limbic system, so that’s why a painful memory can increase blood pressure. Figure 13.15 • BRAIN STEM – MIDBRAIN – PONS – MEDULLA OBLONGATA Midbrain The top of the brain stem is the MIDBRAIN. It controls automatic behaviors (fight or flight) The midbrain also contains a pigmented area called the substantia nigra. The Substantia nigra is involved in addictions and in initiating body movement. The substantia nigra secretes the neurotransmitter dopamine. When the neurons in the substantia nigra become damaged, dopamine levels decrease, causing Parkinson's Disease. Treatment is to replace the dopamine Dopamine Remember that acetylcholine is the neurotransmitter that functions to contract skeletal muscles? There are many other types of neurotransmitters as well. One is called dopamine. Dopamine is the neurotransmitter that controls the flow of information between various areas of the brain. Dopamine is lacking in Parkinson's Disease, in which the person has muscular rigidity and tremors, so they lose the ability to start movements. They need a service dog to help them get out of a chair or to take a first step. They have a pill-rolling tremor at rest. Corpora Quadrigemina “Quadruplet bodies” They control visual and audio (hearing) reflexes. Throw something at your face, you blink = visual reflex. Loud noise (BANG!) causing a startle, is the audio reflex. The two superior bodies are for eye blinking and fast eye movements. The two inferior bodies are for sound reflexes The corpora quadrigemina are linked to the midbrain. Corpora quadrigemina Midbrain Pons Farther down the brainstem is the PONS, which relays sensory information between the cerebellum and cerebrum. Spinal cord Medulla Midbrain Pons Oblongata Midbrain Pons Medulla Oblongata Medulla Oblongata At the base of the brainstem is the MEDULLA OBLONGATA, which contains areas for heart rate, blood pressure, and breathing. Damage here causes coma. Swelling from an injury causes pressure, which can damage this area, which can cause a coma. Concussions cause nausea and a decrease in blood pressure; patients with these symptoms need an MRI to see if this is early signs of damage to medulla oblongata Boxers who are knocked out can recover, but repeated knock-outs can cause permanent brain damage. What’s the difference in function between the medulla oblongata and the hypothalamus? The hypothalamus is responsible for certain metabolic processes and other activities of the Autonomic Nervous System. It synthesizes and secretes hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones. By secreting hormones, the hypothalamus controls body temperature, hunger, thirst, fatigue, sleep, blood pressure, autonomic nervous reflexes, and circadian cycles. What’s the difference in function between the medulla oblongata and the hypothalamus? The medulla oblongata contains the cardiac, respiratory, vomiting and vasomotor centers and also deals with autonomic functions, such as breathing, heart rate and blood pressure. However, the medulla oblongata does NOT control temperature, autonomic nervous reflexes, hunger, and sleep…only the hypothalamus performs those functions. The medulla oblongata controls blood pressure directly, and the hypothalamus controls it indirectly, by way of hormones. Reticular Formation The reticular formation is a group of cells scattered throughout the brainstem. They play a role in rousing and maintaining consciousness. Melatonin in animals Hormone found in animals, plants, and microbes. In animals, circulating levels of melatonin vary in a daily cycle, thereby allowing the circadian rhythms of several biological functions. It allows reptiles to change the color of their skin The change in duration of secretion thus serves as a biological signal for seasonal reproduction, behavior, coat growth, and camouflage coloring in animals. Melatonin in humans Infants' melatonin levels become regular in about the third month after birth, so they sleep . Production of melatonin by the pineal gland is inhibited by light and permitted by darkness. Secretion peaks in the middle of the night, with normal variations in timing according to an individual's chronotype. A chronotype is an attribute reflecting at what time of the day their physical functions (hormone level, body temperature, cognitive faculties, eating and sleeping) are active, change, or reach a certain level. Are you a morning person or a night owl? Other effects of melatonin Melatonin stimulates the immune system It is an antioxidant, protecting mitochondrial DNA It increases REM sleep time (dreaming) It causes the onset of puberty Melatonin is mainly secreted by the pineal body. PINEAL BODY The PINEAL BODY secretes melatonin. How much it secretes depends on the sensory information it receives from the eyes about how many hour of daylight are present. The amount of melanin secreted and circulating in the blood then determines the circadian rhythm, or the biological clock (cycles influenced by light). Therefore, the pineal body detects the number of hours of light and dark, and sets the body’s 24- hour clock. Thalamus Pineal body Pineal body JET LAG When you get jet lag, it’s because the information it gets doesn’t match with where you are. You can help yourself get over jet lag by being outdoors in the daylight and being indoors at night, and the pineal body with reset the clock. Chronic Insomnia First eliminate caffeine and alcohol, then modify the diet (no sugars) and increase exercise. Ambien (a sleep med) can cause people to sleep walk, and even drive in their sleep! CEREBELLUM The cerebellum is the second largest portion of the brain, is responsible for balance and muscle coordination, and is a comparator. CEREBELLUM The cerebellum functions as a comparator. Action potentials from the cerebral motor cortex descend into the spinal cord to move the muscles. There are branches that are sent to the cerebellum to give it information on the intended movement. At the same time, the cerebellum receives information from proprioreception neurons (sensory, tell what position each body part is in). The cerebellum compares all this information to allow smooth movements. That is why it is called a comparator. FUNCTIONAL REGIONS A. MOTOR AREAS B. SENSORY AREAS C. HIGHER FUNCTIONS Functional and Structural Areas of the Cerebral Cortex Figure 13.11a MOTOR AREAS PRIMARY MOTOR CORTEX PRIMARY MOTOR ASSOCIATION AREA CORTEX AND ASSOCIATION AREAS Each area of the brain has a region where the sensory information comes in, and another area where the information is understood. The area where the information comes in is a cortex, and the area where it is understood is the association area. Therefore, there will be a motor cortex and association area, a visual cortex and association area, an auditory cortex and association area, and a somatic (sense of touch) cortex and association area. MOTOR AREAS 1. PRIMARY MOTOR CORTEX 2. PRIMARY MOTOR ASSOCIATION AREA 1 2 PRIMARY MOTOR CORTEX Contains UPPER MOTOR NEURONS, which extend down the spinal cord and synapse on LOWER MOTOR NEURONS which then leave the spinal cord to innervate every skeletal muscle. Some muscles have more motor units than others (hands, eyes, etc). Upper and Lower Motor Neurons Lower motor neuron is here. The upper motor neuron comes down from the brain and synapses on this neuron. Figure 12.11 PRIMARY MOTOR ASSOCIATION AREA Located just anterior to the primary motor cortex. A. Learned motor skills: these are preprogrammed skills, like when you know how to type or swing a golf club. You practiced it so often, it’s now automatic. When someone asks you how to spell a word, but you can’t do it until you write it out, it’s because that memory is now a motor skill. The same happens when you know how to tie your own shoelace or necktie, but can’t tie another’s; it initially is learned by repetition. Then, to do it later triggers a series of information which turns on those muscles in the right order. PRIMARY MOTOR ASSOCIATION AREA B. Planning movement: This is when you plan to reach for a new item. You have not rehearsed it, but you know to extend your forearms, lift, etc. A signal is sent to the primary motor cortex to turn on specific motor units to do that. Damage from a stroke= loose function to that area, but you can compensate by using other muscles, and re-learn that movement. Fun Fact Use your right foot to draw a clockwise circle in the air. While keeping your foot going, draw the number “6” in the air with your right hand. Did your foot start moving counter-clockwise? Pre-Central Gyrus Pre-Central Gyrus Within the primary motor area of the brain, there is a structure called the pre-central gyrus which contains a precise map of the different body parts. This map is called a motor homunculus (Latin: little man) All the neurons that innervate the lips would have their cell bodies in one particular region in this area. All the neurons that innervate the hands have their cell bodies in this area. All those that innervate the back have their cell bodies here. However, we don’t have as many neurons innervating the back as we do for the lips and hands. The homunculus is drawn to represent how many neuron cell bodies we have that innervate each region of our body. Pre-Central Gyrus Not all body parts are equally represented by cell density in the motor area in proportion to their size in the body. Lips, parts of the face and hands enjoy especially large areas of cells in the motor area. The reason the face region of the homunculus is so large relates to the fact that we have very expressive faces. There is also a somatosensory homunculus. Accepted depiction of the homunculus Perhaps this is a more accurate depiction of the homunculus? FUNCTIONAL REGIONS A. MOTOR AREAS B. SENSORY AREAS C. HIGHER FUNCTIONS SENSORY AREAS PRIMARY SOMATOSENSORY CORTEX Somatic = touch SOMATOSENSORY ASSOCIATION AREA PRIMARY VISUAL CORTEX VISUAL ASSOCIATION AREA PRIMARY AUDITORY CORTEX AUDITORY ASSOCIATION AREA SOMATOSENSORY AREAS 1. Primary somatosensory cortex 2. Somatosensory association area The primary somatosensory cortex receives signals for touch and pressure. 1 The somatosensory 2 association area interprets the sensation. When I put my hand in my pocket, I know that is my keys I am feeling. VISUAL AREAS 1. Primary visual cortex 2. Visual association area The primary visual cortex receives signals from the optic nerves. The visual association area interprets the signals. When I look at my keys, I can identify them as keys. 2 1 VISUAL ASSOCIATION AREA Within the visual association area is a region called Brodmann areas 18 +19. Damage to this area results in an inability to recognize what one sees. The person can see a chair in their way, move around it, but they can’t identify the object as a chair. Some people with this damage can’t distinguish one person from another because they can’t recognize their faces. For more information on these types of brain damages, there’s a book called The Man Who Mistook his Wife for a Hat. HEARING AREAS 1. Primary auditory cortex 2. Auditory association area The primary auditory cortex receives signals from the ear. The auditory association area interprets the signals. When I hear a sound, I can tell you 1 2 what it is that I am hearing. AUDITORY AREA The auditory area is where language is formed. Language is natural to humans. A group of deaf children in South America were found to have created their own language, using nouns, verbs, pronouns, adjectives, and everything, even though no one there knew any sign language to teach them. There are certain strokes that cause injury to this area, and the person can’t use adjectives, but everything else is normal! Auditory Association Area • The auditory association area contains two special regions • BROCA'S AREA is a region of the brain that allows for speech. – Injury (stroke) in this location causes impairment of speaking certain words. They know what they want to say, they just cannot get the words out. Not being able to speak at all is called aphasia. • WERNICKE’S AREA is the region of the brain that allows understanding of words. • It does not affect a person’s speech. • They can say what they want to, but they cannot comprehend someone else’s speech. Fun Fact Deaf people are not using their auditory cortex and association area, but that region of the brain is not left inactive. Signals from the optic nerve branch out and synapse there, and they use that area of the brain to develop better peripheral vision. Blind people are not using their visual cortex and association area, so that region of the brain is used to develop more fine motor connections for their sense of touch. As they learn to read Braille, they develop synapses for fine touch in the visual areas of the brain. They can discern the small bumps of print with their fingers better than a sighted person. FUNCTIONAL REGIONS A. MOTOR AREAS B. SENSORY AREAS C. HIGHER FUNCTIONS For a great video of a neurologist describing what it felt like when she had a stroke: http://www.ted.com/talks/lang/eng/jill_bolte_taylor_s_powerful_stroke_of_insight.html HIGHER FUNCTIONS 1. PLANNING AND JUDGMENT 2. MEMORY 3. EMOTIONS 4. INTERPRETATION OF STIMULI 5. BIOLOGICAL CLOCK 6. REFLEXES 7. BREATHING 8. CONSCIOUSNESS 9. BALANCE HIGHER FUNCTIONS 1. PLANNING AND JUDGMENT 2. MEMORY 3. EMOTIONS PLANNING AND JUDGMENT This is coordinated by the frontal lobe: How much time do you need to be ready for the test? This is calculated by the frontal lobe. Damage to the frontal lobe causes people to become docile and do what they are told. 1930’s when people were overly aggressive, they did a frontal lobotomy by going up the eyelid, crack through the skull, and stirring up the brain. The problem is that it permanently altered their personalities. Stopped in 1960’s; we do it with drugs now (Ritalin). PLANNING AND JUDGMENT There was a 16 year old rebel who shot himself in the head, but went to far forward, and his personality improved! Ritalin suppresses CNS in children, stimulates it in adults. In a criminal psych ward, an inmate with a lobotomy got his hand caught in the electric door, and while his hand was dangling half off, a nurse asked him if it hurt, and he just calmly said, “Yes, quite a lot.” No emotion. Remember, when you kill a neuron, it does not regenerate; it’s gone forever. MEMORY: HIPPOCAMPUS We talked about motor memory. You can also have memory of events. This is controlled by the HIPPOCAMPUS (“sea horse”; that’s its shape). The hippocampus plays a major role in storing and retrieving memories. But memories are not stored there or in any other single site in the brain. They are stored throughout the brain, especially in the cerebral cortex. Memory: Hippocampus Hippocampus Memory Memory consists of four processes Encoding: during exposure to new thing Consolidation: short-term memory forms; retained for a few seconds to a few minutes. The average person can only remember about 7 new things at a time in a few minutes. When new information is presented, old information in short term memory is eliminated. If temporal lobe is damaged, consolidation may not occur and the person only remembers things learned in the last few minutes plus things stored in long-term memory, before the injury. Storage: long-term memory forms for a few minutes to permanently, depending on how often it is retrieved and used. Retrieval: using the stored information Memory To convert short-term memory into long-term memory, you should learn things in a variety of ways: Prepare Listen Write notes Review daily Watch videos Do labs This allows easy access to that information again by going through the hippocampus. MEMORY The reason we sleep is to allow our brains to form memories. Anything with a strong emotional attachment will form a stronger memory during the sleep process. Whatever you are afraid of during the day, you will dream about more, and remember more. You will have more nightmares if you watch a disturbing TV show before going to bed. If you have nightmares about your personal life, stop dwelling on those things during the day! Resolve your conflicts while you are awake, and you will sleep better. The best way to remember what you study is to go over it before going to bed. Study with fear and you will remember it more! Mammilary Bodies A pair of small round bodies at the anterior end of the fornix Part of the diencephalon; they form part of the limbic system. They relay information (recognition memory) from the hippocampus. They also add the element of smell to memories. Damage to the mammillary bodies due to thiamine deficiency or alcohol causes Wernicke-Korsakoff syndrome (anterograde amnesia) Sheep brain Fornix Mammilary body Fornix Mammilary body Fornix Carries signals from the hippocampus to the mammillary bodies. ANTEROGRADE AMNESIA Damage to the mammillary bodies or hippocampus; they remember things before the injury occurred, but all new information is lost within minutes. Nemo’s fish friend, Dori, has this type of amnesia. You can get around it by motor memory. Give an amnesiac a new puzzle; they’ll do it in 30 mins. The next day, they don’t recognize the puzzle, but they do it in 20 mins, the next day in 10. Therefore, they are learning by motor memory. They can learn their route from home to the market by repetition. But they can’t make a detour, and if anything bumps them off track, they’ll be lost. RETROGRADE AMNESIA Retrograde amnesia is a form of amnesia where someone is unable to recall events that occurred before the development of the amnesia. Retrograde amnesia is caused by trauma that results in brain injury. Retrograde amnesia is often temporally graded, meaning that remote memories are more easily accessible than events occurring just prior to the trauma. Events nearest in time to the event that caused memory loss may never be recovered. They can remember new things. STROKES A hemorrhage in the brain (broken blood vessel) deprives an area of the brain of oxygen. This is called a stroke. It is one of the most likely causes of amnesia. Amnesia that is caused by a blow to the head is not cured by a second blow! Another problem with memory: ALZHEIMER’S DISEASE Dementia is a symptom, not a disease. Dementia is loss of memory. Alzheimer’s disease is the most common form of dementia. About 10% of people over the age of 65 and 50% of people over the age 85 suffer from it. It is irreversible, incurable, and fatal (6th leading cause of death in the USA, surpassing diabetes). The person dies because they can no longer eat, swallow, etc. There are treatments to delay symptoms. Normal Brain vs. Alzheimer’s Alzheimer’s Disease vs. other dementia Alzheimer's disease is typically a slowly progressive disorder that involves memory for recent information (short-term memory) and one or more other abilities, such as speech and language, personality, decision-making and judgment or awareness and ability to interact with the environment. Abilities that are typically not impaired in a patient with Alzheimer's disease include memory for information of long ago (long-term memory), vision, ability to feel things and muscle strength. Memory Even when these memory systems are working well, some memories will be stored or recalled more easily than others. A memory with a strong emotional component, such as where you were on September 11, 2001, will likely be retained for the rest of your life. Information is also more likely to be stored properly when it is recognized as important. Memory New information is also more likely to be retained and recalled if it is related to information that is already stored. The links between the new and old information serve as retrieval clues. The more numerous the links and the stronger the associations, the more accessible and clear the memory will be. However, if the new information is too similar or two different from an existing memory, it may be discarded. Forging new memories depends in large part on staying interested, active, and alert. Learning new things You can’t learn anything brand new; you have to either use repetition or do something to put the new information in your head by associating it with something you are already familiar with. That’s why mnemonics are good. The word “supinate” was a brand new word, but it sounds like “soup”, and its motion looks like you’re holding a bowl of soup, so it’s easy now to remember. Learning new things If the word “cerebrum” is a brand new word, it sounds like “Sir read broom”, which are words you already know and can visualize. Think of Harry Potter asking a wizard to read the strange words on his new broom: “Sir read broom”, and the wizard scratches his brain (cerebrum) as he tries to read the words. Now it’s easy to remember because you can relate it to something you already know and can picture. IMPLANTED MEMORY All memories are created; there is no such thing as real memory. When the Challenger shuttle exploded in the 1980’s, a freshman college professor told his students to write down where they were and what they were doing when they heard about it. Four years later, he asked them again. 65% answered the same way, but 35% remembered it completely differently, but the students insisted they were right. IMPLANTED MEMORY Another college professor found all the freshmen students with older siblings at the college, and he told the older siblings to tell this story to their younger siblings: “When you were 5, we went to a fancy restaurant to celebrate mom’s birthday, and you spilled something on her dress and you were really embarrassed.” A few weeks later, the professor asked the freshmen to write down a story about anything embarrassing that happened to them when they were five, and to include all the details they remembered. The freshmen recounted the fake story as though it was real because they thought they remembered it. They also included details that they were not told, such as the name of the restaurant, the color of the dress, and what was spilled. The freshmen filled in the story to make a complete memory. MEMORY LAPSES More likely to occur when a person is tired, sick, distracted, or under stress. People who are depressed are also more likely to have memory problems. The brain contains about 100 billion neurons. Only a few neurons die over a person's lifetime, but they do shrink. This shrinkage may partially explain why mental functioning slows down in middle and older age. Attention Deficit Disorder Memory aids Place all commonly lost items in a designated spot. Write things down Concentrate and relax Get plenty of sleep Say words out loud: saying” I have turned off the stove” after you have done so will give you a verbal reminder when you later charged recall whether the stove is still on. Incorporating people’s names into the conversation immediately after you have met them serves the same purpose. Use memory aids: use a pocket notepad, personal digital assistant, wristwatch alarm, or voice recorder to help you remember what you need to do more to keep track of information. Memory aids Use visual images: when learning new information, such as a persons name, create a visual image in your mind to make the information more vivid and more memorable. If you have just been introduced to Mr. Hackman, visualize him hacking his way through a dense jungle with a machete. Group items using mnemonics: when memorizing lists, names, addresses, and so on, alphabetize them or group them into an acronym -- a word made from the first letter of a series of words. You could also use the first letter of each word to create new words to form sentences or phrase. You can use rhymes or create a story that connects each element to be remembered. The more compact or meaningful the mnemonic, the easier it will be to remember the information. EMOTIONS: LIMBIC SYSTEM The prefrontal lobe and the hippocampus are part of a system of structures in the brain. The LIMBIC SYSTEM also includes the olfactory nerves (sense of smell). Therefore, memory, emotion, and smell are linked. Crayolas are created today with the same scent because it reminds people of their happy times in childhood. Why is the brain formed so that smell and emotions are tied together? Because pheromones are tied to emotions and behavior, so they need the link. The Limbic System (everything in orange) Figure 13.23 Limbic System The limbic system includes the olfactory cortex (sense of smell), and portions of the diencephalon and cerebrum It influences emotions, motivations, and mood It is functionally associated with the hypothalamus It initiates responses necessary for survival, such as hunger and thirst. MENINGES • These are tissues that cover the entire CNS. They are three layers that serve to protect and cushion the brain. Meninges 1. DURA MATER is the thickest and most superficial of the meninges. 2. ARACHNOID MATER is the middle layer and is not nearly as dense. It also does not go down into the sulci, it only covers over the top of the gyri. 3. PIA MATER is the thin, shiny layer that DOES follow the brain surface into the sulci. SUBDURAL SPACE is between the dura mater and the arachnoid mater. The SUBARACHNOID SPACE is between the arachnoid and pia mater, and is filled with CEREBRAL SPINAL FLUID (CSF). 1. DURA MATER (“Tough mother”) Dense regular connective tissue. It consists of two layers. Under the skull is the first layer of dura mater, called the PERIOSTEAL LAYER. Just under this is the second layer, called the MENINGEAL LAYER. There are these two layers everywhere except around the spinal cord, where it’s just one layer, the meningeal layer of the dura mater; no periosteal layer. Between the meningeal and periosteal layers of the dura mater are DURAL SINUSES, which are filled with venous blood which is drained from the brain. Dural sinus and subarachnoid space Clinical Significance In the spinal cord, between L3 and L4, a doctor can inject anesthetic above the dura mater, so only the nerves are affected. What is that called? Epidural. The dura and arachnoid mater both have lots of blood vessels, which might rupture in an injury, called a SUBDURAL or SUBARACHNOID HEMORRHAGE, which is potentially fatal. Blood accumulates and squeezes the brain. Treatment = drill a hole. VENTRICLES OF THE BRAIN The brain and spinal cord are hollow, filled with CSF = ventricles They are extensive. The names are simple. LATERAL VENTRICLE is the largest, extends throughout the cerebrum. THIRD VENTRICLE: in a sheep, it forms a figure “3” under the fornix and around the corpora quadrigemina. In a human model, it looks like a cavity between the fornix and a red arch. FOURTH VENTRICLE is at the base of the cerebellum; it is continuous with the central canal of the spinal cord, and also with the subarachnoid space. CEREBRAL AQUEDUCT: connects the 3rd and 4th ventricles. The ventricles, subarachnoid space , and cerebral aqueduct are filled with CSF. The subdural space is NOT filled with CSF; it is filled with venous blood. VENTRICLES OF THE BRAIN (blue) Figure 13.6a, b Fornix 3rd ventricle Mammilary body Lateral ventricle Cerebral aqueduct Fourth ventricle Sheep brain Third ventricle Lateral ventricle (forms a number “3”) Fourth ventricle Cerebral aqueduct CerebroSpinal Fluid (CSF) CSF is similar to plasma because it is derived from plasma. CSF is made in the ventricles by a group of capillaries called the CHOROID PLEXUS. The choroid plexus capillaries have holes that allow the blood plasma to leak into the subarachnoid space. It is now called cerebrospinal fluid (CSF). CerebroSpinal Fluid (CSF) The CSF that has been depleted of its nutrients is absorbed back into the blood through the ARACHOID GRANULATIONS. Arachnoid granulations are small protrusions of the arachnoid mater (the thin second layer covering the brain) through the dura mater (the thick outer layer). They protrude into the venous sinuses of the brain, and allow cerebrospinal fluid (CSF) to exit the brain, and enter the blood stream. 800ml of CSF is made per day, but there is actually only 150 ml there because the extra is continually absorbed in the dural sinus through the arachnoid villa, which are valves that release the CSF back into the blood. FUNCTION OF FLUID-FILLED VENTRICLES 1. Allows the brain to float. The brain has the consistency of Jell-O, and weighs three pounds. Its weight would crush the inferior structures if it didn’t float. 2. It cushions. In sudden movement, like riding a bike into a tree, and hitting the head on the tree, the brain hits inside the skull in the front, and then in recoil it hits the back of the skull = closed head injury, not necessarily with a fracture. 3. Acts as the lymphatic system of the brain (it doesn’t have one). Protection of the Brain – Cerebrospinal Fluid (CSF) Figure 13.27b PROBLEMS WITH MENIGES HYDROCEPHALY is accumulation of CSF inside the ventricles. It is usually congenital, caused by a blockage of the cerebral aqueduct. The CSF is made but can’t leave, and the brain gets expanded. The skull bones in a newborn can expand, so although it CAN damage the brain, it does NOT cause mental retardation. The head becomes enlarged. Treatment is to put in a tube to drain it. Hydrocephaly in adults can be caused by a tumor, and since the skull no longer expands, it’s very dangerous. HYDROCEPHALY MENINGITIS Meningitis is inflammation of the meninges. Can be caused from bacteria (can be fatal in 24 hours) or virus (fatal in a week or more). The main symptom is a headache, so when this occurs in an infant, they can’t say where they hurt. So when an infant presents with a high fever of 104˚ with no other symptoms, they might test for meningitis, because if they miss it, it’s fatal. The test is a SPINAL TAP, where a needle is inserted between L4 and L5 because that is below the level of the spinal cord. They draw the CSF to look at. It it’s cloudy or bloody, it’s usually meningitis. Untreated meningitis can lead to this next one: ENCEPHALITIS This is inflammation of the brain. It can be caused by mosquito-borne illnesses, or bacteria. Why is infection of the brain so dangerous? The swelling crushes the brain. Any injury may lead to brain swelling. Treatment is to remove a piece of the skull bone to allow the swelling. Aging Aging affects the nervous system Decline in sensory functions Decline in motor functions Insomnia Decline in short-term memory Electroencephalogram (EEG) Brain Wave Activity is recorded on an EEG Not to be confused with an EKG, which is for the heart. Brain Waves Types of brain waves Alpha (active during wakeful relaxation of closed eyes, such as meditation, prayer). When you pray or meditate for a long time, you feel refreshed! Beta (active when learning, thinking and concentrating) Theta (active when just falling asleep) Delta (active during deepest stage of sleep) Pleasure Centers of the Brain • Experiment: put a rat on one side of the cage and its food on the other side. Put an electric mat on the bottom of the cage so it gets shocked if it tries to run across the flood of the cage to get to the food. • One rat has an electrode inserted into its brain to stimulate the pleasure center when it reaches the food. Only one stimulation per trip, though! – This rat will run across immediately, and will run back and forth to the food many times, even though it gets shocked on the way there, just so it can experience the pleasure jolt. • Another rat gets no stimulation. This rat will starve to death rather than experience the shock. • You can get a rat to go to an area that you have chosen by stimulating its pleasure center every time it goes near there. Human Experiments We can figure out how the brain works by examining people’s motor and sensory abilities after a head injury, and comparing them to normal. A brain tumor can sometimes cause epilepsy. If the surgery does not show where the tumor is, the patient needs to be under mild sedation only, so they can probe the area, get feedback from the patient, and see the results. That’s how they can find the tumor. Brain Tumor Therapies Gamma Knife Therapy The gamma knife and its associated computerized treatment planning software enable physicians to locate and irradiate relatively small targets in the head (mostly inside the brain) with extremely high precision. Intense doses of radiation can be given to the targeted area(s) while largely sparing the surrounding tissues. The gamma knife is usually unsuitable for targets larger than three or four centimeters in size. Gamma Knife Therapy The target is placed exactly in the center of approximately 200 precision-aimed, converging beams of (Cobalt-60 generated) gamma radiation. Treatment takes anywhere from several minutes to a few hours to complete depending on the shape and size of the target and the dose required. Patients do not feel the radiation. Following treatment the headframe is removed and the patient may return to normal activity. Gamma Knife Therapy Tumor-Starving Therapy: Avastin Avastin is an innovative tumor-starving therapy designed to block the VEGF (Vascular Endothelial Growth Factor) protein that is produced by normal cells and overproduced by cancer cells, and is needed for cell growth. Avastin is not chemotherapy and therefore works differently. VEGF is important for the formation of blood vessels. Tumors rely on blood vessels to get the nutrients and oxygen they need to survive. How do drugs affect the brain? Alcohol Drugs Nicotine DRUG ABUSE Many drugs can alter the mood or emotional state, but they also have other side effects. Drug abuse quickly leads to dependence, which is when a person spends much time thinking about the drug or arranging to get it and they take more of the drug than was intended because they develop tolerance to it and then need more to get the same effect. They get withdrawal symptoms when they try to stop. Drug use occurs when people want to avoid dealing with their personal problems and unpleasant emotions. ALCOHOL Alcohol affects the cerebellum (balance area of the brain) You can see that area of the brain has been affected by alcohol because you cannot walk a straight line or close your eyes and touch your finger to your nose. ALCOHOL Alcohol is metabolized (broken down) in the liver, where it disrupts the normal working of the liver so that fats cannot be broken down, and they accumulate. This fat accumulation, which is the first stage of liver deterioration, begins after only one night of heavy drinking. If the drinking continues, scar tissue appears in the second stage. If the drinking stops, the liver can still recover and become normal again. If not, the final stage, cirrhosis of the liver occurs, and the liver cells die and harden and cannot be repaired. Alcohol crosses the placenta in pregnant women and causes fetal alcohol syndrome, which is characterized by mental retardation. NICOTINE This is from tobacco, and it quickly goes into the entire nervous system and is highly addictive. It also increases the heart rate and blood pressure. Withdrawal symptoms include headache, irritability, and insomnia. Lung cancer has passed breast cancer as a cause of death. Nicotine also causes harm to the fetus. Interestingly, alcohol is the most toxic drug available (more toxic than illegal drugs) and tobacco is the most addictive, yet these two substances are legal. COCAINE A cocaine binge can go on for days, after which the individual suffers from a crash. The cocaine high is followed by depression because it depletes dopamine. That’s why their mood does not just return to normal. During the binge, the person has no desire for food or sleep. During the crash, the user is tired, depressed, irritable, and has memory and concentration problems. It usually winds up causing a loss of sex drive and impotence. Too much can cause seizures and cause the heart to stop beating and the lungs to stop breathing. Babies born to addicts suffer brain and developmental problems. If someone uses cocaine every day for 30 days, there is a 100% chance of becoming addicted. HEROIN Side effects include nausea, vomiting, and a decrease in breathing and circulation, which can cause death. The user becomes so tolerant to it, they have to take more and more of it just to prevent the withdrawal symptoms. These symptoms include sweating, shakes, abdominal cramps, and an increase in heart rate. Infants born of addicts also suffer these withdrawal symptoms. MARIJUANA This causes alteration in vision, judgment, and motor coordination. Causes distortions of space and time. They lack motor coordination, including the ability to speak in a way that is understandable. Heavy use causes hallucinations, anxiety, depression, body image distortion, paranoia and loss of sense of reality. Long term use can lead to brain impairment.