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Download Biological Aspects of Psychology
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Brain, Body, & Behavior NERVOUS SYTEM NEURONS BRAIN NEUROTRANSMITTERS ENDOCRINE SYSTEM IMMUNE SYSTEM DID YOU KNOW THAT… Some cells in your nervous system are more than 3 feet long? Our bodies produce natural painkillers similar to some narcotic drugs? 95% of fetuses suck their right thumbs? Raising the body temp. of a finger may relieve the pain of a migraine headache? Men’s & women’s bodies produce both male & female sex hormones? Intro ALL behaviors & mental processes are influenced by or based on biology ◦ study the brain in detail Behaviors & mental processes can’t be fully understood through bio alone!!! • Oversimplify = not credible AVOID THE “BIOLOGY IS DESTINY” PITFALL ◦WE ARE THE PRODUCT OF AN INTRICATE INTERACTION OF BIO. & ENVIRONMENTAL FACTORS NERVOUS SYSTEM NERVOUS SYSTEM Brain, spinal cord, nerves processes info. from: ◦ 1) inside the body ◦ 2) external environ. NEURONS ◦ cells in the nervous system (brain cells & nerve cells ◦ Specialized to respond to signals & send signals of their own 3 Main Functions INPUT: receiving info. about what is going on inside & outside (senses) your body PROCESSING: combining info. with past experiences (if any) & decide how to react/behave OUTPUT: brain activates muscles to act on what to do about it (the info. received) INPUT PROCESSING OUTPUT Q: How can the nervous system do this? ◦A: Neurons! must COMMUNICATE Neurotransmitters Electrical signals 100 billion neurons that are separate but still able to alternate signals from one circuit to another DIVISIONS • 1) CENTRAL NERVOUS SYSTEM • brain & spinal cord • Info is sent here from PNS to be shot up the spinal cord to the brain to be processed . –The ‘CEO’ of the nervous system 2) PERIPHERAL NERVOUS SYTEM ◦all nerves not in the brain & spinal cord. ◦PNS collects info. to be sent to the CNS. 2 subdivisions of PNS ◦Somatic: sensory nerves & motor nerves ◦Autonomic: Automatic processes Signals must make a ‘full circuit’ in order for you to process sensory & motor info Peripheral nerves spinal cord brain spinal cord original peripheral nerves Nerve NEURONS cell more advanced than your typical cell ◦ involved w/ receiving, moving, & processing info. PARTS Cell Body Receptor Dendrites Axon Synapse Vesicles Neurotransmitters Myelin Axon terminals PARTS OF THE NEURON Cell Body: contains a nucleus that caries DNA info; determines how the cell functions Dendrites: fibers of the neuron that receive signals/info from the axons of other neurons. Dendrites Detect signals from other neurons ◦Carries the signals to the cell body to be interpreted Axon: fibers that carry signals away from the cell body to where communication occurs with other neurons. Axons carry signals Away from the cell body to axon terminals Axon Terminal: areas @ the end of an axon where neurotransmitters are released Synapse: gap between neurons. Where neurotransmitters “jump” from one neuron to another. Neurotransmitters: chemicals that transfer information from one neuron to another by “jumping” across the synapse. ◦ can only “fit” into its own receptors Vesicles: Little “bubbles” where neurotransmitters are stored at the end of an axon. Receptor: where neurotransmitters fit into the receiving dendrite of the next neuron. Myelin sheath: insulating protein layer that surrounds the axon in order to speed up communication & contain the electric pulses. HOW DO NEURONS COMMUNICATE? Dendrites accept neurotransmitters from other neurons and transfer that info to the cell body. That info is shot down the axon in the form of electrical signals. When these electrical signals reach the end of the axon, it releases the neurotransmitters (chemical signals) from the vesicles. The neurotransmitters “jump” across the gap between neurons, known as the synapse. The neurotransmitters then bind to their proper receptors on the dendrites of the receiving neuron (like a puzzle). ◦ Dendrites get excited when they detect neurotransmitters in their receptors & send info. to the cell body. THE WHOLE PROCESS STARTS OVER ‘CLOSE UP’ VIEW OF NEURAL COMMUNICATION BTW 2 NEURONS Rules of Neural Communication 1) NEURONS EITHER FIRE OR DON’T FIRE. IT’S “ALL OR NOTHING” ◦ rate of firing can differ 2) Can only communicate w/ other neurons that are close to them. 3) MUST MAKE FULL CIRCUIT! ◦ Nerves spinal cord brain spinal cord same nerves When you are ‘killing brain cells’, you are killing NEURONS & CONNECTIONS! LOU GEHRIG’S DISEASE Wasting away of motor neurons in brain & spinal cord Progressive, disabling, & fatal Symptoms inability to control mvmt, loss of muscle control Neurons waste away = muscles waste away too AUTISM Brain dev. disorder – abnormalities & deficits in: ◦ Social interaction ◦ Restricted interests & repetitive behavior Deficit in mirror neurons (?) Probs empathizing w/ & imitate others MULTIPLE SCLEROSIS (MS) Immune system slowly destroys Myelin sheaths Slows communication Progressive & fatal 350,000 Americans onset = 20 – 40 yrs old Symptoms: loss of the ability to speak, walk, write, eventually breath & heartbeat THE BRAIN THAT MAGNIFICENT BRAIN OF YOURS! Sits in a fluid There are psych. changes when the brain experiences trauma or chemical changes . DIVIDED INTO 3 MAIN PARTS ◦ a.k.a ‘the 3 brains’ ◦ each contains specialized structures most HINDBRAIN primitive part; vitals Incoming signals reach here 1st Medulla: vital bodily functions (breathing, swallowing, circulation) Reticular Formation: “net”work of fibers (neurons); arousal & attn Cerebellum: basic motor activities; coordination (sequencing/ timing); posture, balance, normal speech patterns MIDBRAIN Integrates mvmt w. sensory info, & relays it up to the rest of the brain ◦ Ex. Loud noise turn in head in direction of the sound FOREBRAIN most complex aspects Thalamus: relay station for sending messages to & from parts of the brain Hypothalamus: ‘pleasure center’; regulates hunger, thirst & sex drive; controls rage Hippocampus: regulate emotion & form LT memories Cerebrum: high level thinking process ◦ Emotions, memories, personality, logic, decision making, planning, etc. ◦ Largest part ◦ Div. into 2 hemispheres (halves) & 8 lobes Cerebrum Whole brain Corpus Callosum –band of fibers in the mid of the brain – connects the 2 hem. LOBES of CEREBRUM Cerebrum / 4 lobes ◦Each is specialized ◦all work together in order to collect, analyze, store, & respond to information All 4 lobes are found in both hemispheres (mirror image) Deep groves in the brain mark where the difft lobes are PARIETAL ◦body & skin sensations ◦Touch, pressure, temp., pain, movement TEMPORAL ◦sound sensations ◦auditory info; involved in hearing, memory, speaking OCCIPITAL ◦ visual info (vision center) ◦ Optic nerves directly connected to here FRONTAL ◦ Arranges incoming info into meaningful perceptions Most advanced cog. processes ◦ Language, organizing, planning, problem solving, decision making, personality, learning, dreaming, emotions, memories, creativity, & thinking ◦ Control of the body POOR PHINEAS! major changes in behavior Able to see the connection btw damaged parts of the brain & behavior Why did he survive? Before ◦ friendly; good judgment, cooperative, enjoyable After ◦ short-temper; swore; urinated & undressed in public; said inappropriate things; aggressive; violent; Damage to what lobe? FRONTAL! ◦ Severe changes in personality, judgment, & rational thought ◦ prevented censoring of thoughts, ideas, & social functioning Right & Left Cerebral Hemispheres LATERALIZATION OF THE CEREBRUM Lateralized ◦2 hemispheres are specialized for processing certain kinds of info. Each hem. controls the opposite ½ of the body ◦Right 1/2 controls left side of body ◦Left 1/2 controls right side of body We constantly use both ◦compliment each other ◦Work in harmony to jointly control human functions 2 hems. connected by the corpus callosum. (communication) ◦processed in one half, then sent to the other to be processed… then both ‘analysis’ are integrated to produce one flow of thought & behavior FUNCTIONS/ CHARACTERISTICS LEFT HEMISPHERE ◦LANGUAGE (verbal): speaking, understanding language, reading, writing ◦Sequences & order; time ◦Math: algebra, calculus, physics ◦Detail-oriented ◦‘Safe & logical’ ◦Process info. logical & sequential Right Hemisphere ◦Nonverbal: body language; emotions; visual symbols & images ◦Spatial: patterns; objects in ‘space’; art & music ◦Math: geometry ◦‘Big picture’ oriented ◦‘Impulsive’ ◦Process info. intuitively, simultaneously, & randomly HEMISPHERES & PREFERENCE We tend to ‘prefer’ 1 hemisphere over the other ◦‘dominance’ ◦reflected in the ways we learn best LATERALIZATION & INTEGRATION! Right vs. Left Handedness? Genetics ◦4/5 sets of identical twins have same handedness levels of testosterone during pregnancy ◦Boys 2 x more likely to be ‘lefties’ Handedness dev. prenatally Forcibly imposing a handedness can cause emotional probs & secretive behaviors PARENTS WHO ARE LEFT HANDED Neither parent CHILD’S ODDS 1 in 50 One parent 1 in 6 Both parents 1 in 2 Stare @ the dot (1 min) – stare @ wall ‘SPLIT BRAIN’ STUDIES Separate the 2 hem. by cutting the corpus callosum ◦ Lessens severity/frequency of epileptic seizures Creates 2 independently functioning cerebrums Intelligence, personality, & emotions went unchanged… seem ‘normal’ This changes way people think about & deal w/ the world in 2 major ways: 1) touch: can’t label an object if it’s held in the left hand ◦ word ‘spoon’ shown to lft eye… can’t say what it is but can pick up a spoon among other objects ◦Patients blindfolded & key put in lft hand… can’t say what it is but used it to open a lock 2) vision: can’t describe a picture if seen only by the left eye. ◦Nude pic shown to right eye… laughed & described what they saw ◦Nude pic shown to lft eye… only blushed & smile (emotional rxn) BRAIN ANEURYSM Bulging artery that can rupture 1/15 ppl in U.S. will dev. an aneurysm: ◦ 10% - 15% ‘ruptures’ die before getting to a hospital 50% die w/in 30 days after rupture 50% survivors suffer permanent damage most commonly detected btw ages 35 60 Women to men - 3:2 ratio Genetics, smoking, blood pressure, ethnicity STROKES 3rd leading COD in U.S. ½ mill. ppl/each yr! Blockage of a blood vessel kills brain tissue Impaired abilities depend on where it happens in the brain ◦ lang., coordination, numbness/paralysis of a part on 1 side of the body, hearing, decision-making, etc. BRAIN PLASTICITY Plasticity: ability of the brain to adapt itself after trauma, alteration, or disease ◦ strengthen neural connections @ synapses & est. new ones When 1 part is damaged, another part of the brain may take over its functions (to a certain extent) – compensates! How? Build new circuitry &/or alter existing ◦ Ex. Visual cortex in blind ppl Childhood vs. adulthood Pruning: PRUNING ◦Brain will cut some neural connections & “rewires” itself ◦The neurons w/o connections can no longer be accessed (‘lose’ that info) Which ones are cut? ◦Genetics ◦Experiences (don’t use it, you lose it) How much, which ones, & in what ways the brain prunes can greatly affect cog. abilities Connections that remain are stronger, faster, & more efficient than before! Infancy & childhood ◦ brain “overproduces” neural connections (new experiences & rapid learning) Adolescence ◦ big pruning period! Stare @ the cross only MEN 3D perceptions targeted motor skills Effects of brain trauma more devastating WOMEN recognizing patterns Use more of the brain when processing language *Patterns of brain functioning differs slightly *Sex or gender (?) BATTLE OF THE SEXES NEUROTRANSMITTERS CHEMICALS IN THE ENDINGS OF NEURONS THAT SEND INFO. ACROSS SYNAPSES TO ANOTHER NEURON -- excitatory -- inhibitory WHAT ARE THEY? • Chemical signals (100+) • relay messages/info. from 1 neuron to another • certain behaviors are assoc. w/ certain neurotransmitters • Each circuit specific to an activity • Mvmt circuit, pain circuit, pleasure circuit, etc. Everything you do, feel, or think depends on neurotransmitters!!!!!!! Acetylcholine Arousal (excitatory) Controls the expansion & contraction of muscles; movement ◦ Send info. from 1 nerve cell to another whenever we get ready to move some part of the body. Disorders = Alzheimer’s, inability to make new memories, paralysis Norepinephrine Arousal (excitatory), mood regulation, increases heart rate & contracts blood vessels, stimulates glands to release adrenaline Disorder = depression; prolonged overproduction can cause ‘burn out’ ◦ symptoms resemble paranoid schizophrenia Serotonin Affects sleep, mood/emotion regulation, appetite, aggression, sexuality, & impulse control Body makes it from chemicals in certain foods (carbs, fruits, & veggies), sunlight, exercise Men & women react diff’tly to dramatic drops in serotonin levels ◦ Men – more impulsive; women – more cautious & drop in mood Disorders = SIDS; SAD; Depression Dopamine emotional functioning, motivation, reward ◦Disorders = Parkinson’s Disease, Schizophrenia, addictions Parkinson’s Disease ◦Only disease that is caused by a shortage of a single neurotransmitter! PARKINSON’S DISEASE Degenerative brain disease that leads to a progressive loss of motor function ◦ Dopamine-producing brain neurons in an area of the brain involved in regulating body movement are destroyed Muscle tremors, shakiness, body’s inability to control mvmt, diff. speaking 1 mill Ams – Muhammad Ali & Michael J. Fox ◦ Genetic factors (?) Glutamate Necessary for normal dev. & functioning Memory, learning ◦Strengthens synaptic/neural connections Overactivity (too much glutamate) can kill neurons Disorder = Neuron loss after a stroke or brain trauma (causes memory or skill loss), seizures Endorphins Relieve pain; produce feelings of well-being & pleasure Body’s natural pain killers – fit into receptors that pain messages fit into (block) Similar in chemical structure to narcotic drugs Opiates (heroine, morphine, & opium) bind to the neuron receptors that endorphins usually bind to. ◦ Drugs alter brain chemistry & neural communication! ENDOCRINE SYSTEM WHAT IS IT? Endocrine system is the nervous system’s partner in controlling & coordinating the body’s functions. ◦ Nervous system – neurotransmitters ◦ Endocrine system - hormones Includes Pituitary Gland, Hypothalamus, Thyroid, Pineal gland, Pancreas, Adrenal Glands, Kidneys, Ovaries, Testes. Some glands respond to nervous system messages too WHAT DOES IT DO? Organs in the endocrine system (glands) release hormones (chemical messengers) directly into the bloodstream ◦ Communicate with other organs physical dev, growth, metabolism, sexual behavior, moods, energy, insulin, maturation of reproductive system, stress/ fight-or-flight response (adrenaline & cortisol) Differs in men & women (sex hormones) GLAND / HORMONE FUNCTION Pituitary Stimulates growth; Stimulates -- Growth hormone uterine contractions & milk -- Oxytocin production Hypothalamus -- releasing factors Pineal -- Melatonin Part of the brain that stimulates the pituitary to release hormones Regulates sleep-wake cycles Pancreas -- Insulin Regulates blood sugar levels Thyroid Regulates metabolism, maturation Too much – irritability & anxiety Too little – sluggishness, weight GLAND / HORMONE FUNCTION Adrenal -- epinephrine (adrenaline) -- norepinephrine (noradrenaline) helps body cope w/ stress; speeds up body processes; stimulates liver to release sugars Ovaries -- estrogen -- progesterone Female sexual maturation & menstrual cycle (PMS) Helps maintain pregnancy Testes -- testosterone Promotes sperm production; sex drive; male sexual maturation; makes males during prenatal period IMMUNE SYSTEM serves as both a sensory & surveillance system Detects & destroys unwanted cells and foreign bodies (remembers them) Underresponsive = bacteria & malignant cells run rampant in the body (death?) Overresponsive = attack & kill normal cells in the body (neurons too) PERCEPTION! Seeing is believing? Perception – how you become aware of, know, or identify something (senses) Our mental programming intervenes in everything we perceive. Our minds arrange an image, sound, info to render it ‘acceptable’, or to make it match our knowledge and beliefs. Colorblindness People with normal color vision can perceive numbers formed by patterns of colored dots in every circle. If you do not see some of the numbers, you should have your eyes checked and consider working in a job where color discrimination is not critical. Approximately 6%-8% of people of European descent, 4%-6% of people of Asian descent, and 2%-4% of people of African descent have some type of defective color vision. There are no curved lines in these figures. You can use a ruler to check it out. The diagonal patterns created by the tiny squares distort the perception of the pictures The illusion works because staring at the blue, green and black fatigues cells in our eye (and brain) that are specialized for these colors. When we look at the white wall, other cells which respond to the complementary colors (red, white and blue) are now more active than the fatigued cells and so we experience these new colors in the afterimage. Flag Illusion Ths s prttey cool. There is nothing in motion… what is happening? Afterimages of complementary colors create apparent movement in our peripheral vision as our eyes shift across the page. Movement… When there is none! Afterimages An afterimage is a visual impression that remains in the retina after the initial stimulus is removed. The afterimage always has colors that are complementary to those of the original image. Look steadily at the cross in the center of the picture to see an afterimage. The effect is due to retinal fatigue which occurs when the afterimage of an object cancels the stimulus of the object on the retina. The effect is most pronounced when the objects do not have well-defined edges that are detectable by small eye movements.
