Psych Lecture Notes PDF

Psychology Notes 9/5 Unit 1 Psych is the study of the mind, brain, behavior ○ Psyche = soul, ology = study of Consciousness ○ How does our brain create subjective experiences Identity ○ What is the self? ○ Brain? Body? Experiences? Communities? Selec...

Psychology Notes 9/5 Unit 1 Psych is the study of the mind, brain, behavior ○ Psyche = soul, ology = study of Consciousness ○ How does our brain create subjective experiences Identity ○ What is the self? ○ Brain? Body? Experiences? Communities? Selective attention: our ability to filter out irrelevant info ○ Stroop Test: saying color of words out loud (set 1 color is same as word, set 2 it’s not) ○ Larger Stroop effect shown in people with brain injuries Tools that psychologists use ○ Behavioral tests ○ Observation ○ Imaging and case studies ○ Normal and abnormal populations 9/10: Learning objects ○ Describe early roots of psychology in philosophy and physiology ○ Identify long standing debates Ancient Greek Plato ○ Psyche (soul/breath) determined how people behave Hindu Sage Pantajali ○ Used yoga to treat mental illness Abu Zayd al-Bahki ○ Recognize that both body and soul could be sick Dualism vs Materialism ○ Are the mind and body separate? ○ Mind: set of subjective events – perceptions, memories, thoughts, and feelings ○ Body: physical objects that can be seen, smelled, touched ○ Nature of perception Do we see world exactly as it is ○ Rene Descartes (1596-1650) Argued that the mind and body are separate (dualism) Body is physical container, within that is the spiritual non-physical mind They are lined via the pineal gland (endocrine/hormone secreting tissue)  When you have intention to do something the gland will shift to one side of your body or other, allowing animal spirit to flow into your muscles Questions arose about the interaction between the immaterial mind and the material body → How does body know best foot to put forward? How does mind feel pain caused by physical pain? ○ Materialism Mind is something that is produced by the body Mind is the experience of the brain and body’s mechanics Most psychologists now land on the side of materialism Argue mind is a bundle of behaviors produced by the physical brain Ryle, “no ghost in the brain” Thomas Hobbes (1588-1679) argued for materialism Brain is the mind Every mental phenomena is the result of some physical activity in the brain Philosophical Materialism: view that all mental phenomena are reducible to physical phenomena Realism vs Idealism? ○ Do our senses directly report reality, like a camera (realism) or are we actively building a representation of the world (idealism) ○ John Locke (1632-1704) Philosophical realism: our perceptions of the physical world are a faithful copy of information from the world that enters our brains through our sensory apparatus ○ Modern psych leans towards idealism ○ Retina detect light waves which are sent to rods/cones, sent thru optic nerve (blind spot), usually other eye covers for the blind spot of other When one eye is closed brain makes inferences about what’s actually there Attention span doesn’t perceive the difference ○ Immanual Kant (1724-1804) Philosophical idealism: our perceptions of the physical world are our brain’s interpretation of the info that enters thru our sensory apparatus Light is bouncing off text and hitting your eye and brain is suing that info to produce perception of what you’re seeing ○ Not just reflecting but interpreting Nativism vs empiricism ○ Plato (350 BC) Nativism: at least certain kind of knowledge are innate or inborn Kant also argued that babies must be born with some basic knowledge that allows them to acquire additional knowledge How could you learn without knowing what causation is  Preprogrammed bits of knowledge are not about specific objects but about basic concepts (space, time causality, number) ○ Aristotle Empiricism: knowledge is acquired thru experience (learning) Blank slate argument (Locke) ○ Most modern psychologists embrace some version of nativism ○ Francis Galton (1985) reiterated this as nature vs. nurture debate Localization of function vs mass action ○ Brain organization ○ Phrenology (Franz Josef Gall 1758-1828): Different part of the brains have different functions Brain areas can be overdeveloped = skull bumps Bumps indicates faculties of an individual (personality) ○ Physiognomy: The belief that facial features revealed a person’s character Key figure was Cesare Lombroso (1835-1909), Italian surgeon and criminologist Analyzed prisoners to see if similar crimes had similar features Problematic ○ Pierre Flourens (11774-1867) Experimental brain lesions have different effects Argued for lof but dif locations than phrenology ○ Karl Lashley (1890-1958) Larger lesion = greater impairment regardless of exact location Argued for mass action Taught rats simple things like how to do mazes then cut into dif parts of their brains ○ Paul Broca (1824-1880) Had patient (Legborne) who could only say the word tan, but when he told him to point to certain objects he was able to correctly do so This suggests damage in ability to speak but not ability to comprehend When patient died Broca examined his brain and found damage to left frontal lobe (broca’s area) involved in speech production ○ fMRI Tech that produces brain scans Show the amount of blood that was flowing in different parts of a person’s brain at a particular moment in time Neural activity requires oxygen (which blood supplies) See which areas of brain are processing most info at any particular time Structuralism ○ Hermann von Helmholtz (1821-1894) Studied human reaction time; estimated length of nerve impulse physician/physicist who studied math of vision and hearing  Asked people to close their eyes, respond as quickly as possible when he touched different parts of their legs People took longer to respond when he touched their toes than thighs Found nerves transmit signals to brain indicating that you’re being touched, and since thighs are closer to the brain it takes less time for the signal to travel there Calculated speed at which nerves transmit info ○ Wilhelm Wundt (1832-1920) (research assistant to helmholtz) Consciousness: person’s subjective experience of world and the mind Structuralism: analysis of the basic elements that constitute the mind Attempts to isolate and analyze mind’s basic elements Played big part in establishing psychology as a subject of interest Introspection: subjective observation of one's own experience Pioneered by edward tichener (Wundt’s student) Had people report raw experience instead of their interpretation of it Wundt used introspection to identify three basic dimensions of sensation: pleasure/pain strain/relaxation excitation/quiescence Introspection did not last long as study method as its subjective Functionalism ○ William James Felt subjective experience was not isolable With Dewey and Angell, he developed functionalism ○ Emphasized adaptive significance of mental process Adaptive significance based on Darwin’s evolutionary theory ○ Task for psychologists is to figure out what function of brain is Function is based in evolutionary benefits Overtime there was a separation between psychology and philosophy 9/12 After Flourens, Burkhardt began operating on patients with mental illnesses with the intent of calming (not curing) them, with mixed results ○ Surgical procedures intended for violent and agitated patients were refined, with data from chimps ○ Eventually came up with prefrontal lobotomy Lobotomy: surgical procedure severing the nerves of the frontal lobe Walter Jackson Freeman 2 ○ Afterwards they created transorbital lobotomy (goes thru eye socket without opening skull) ○ Popularized transorbital lobotomy but he was criticized for his poor sterility and careless attitude (was doing them publicly, showing others)  ○ Results Reduced tension/agitation of patients Apathy, lack of initiative, inability to concentrate, blunted emotions, seizures, bleeding death ○ Widely performed in the 1940s, but mostly ended in 60s with the rise of antipsychotic and antidepressant medications Schools of Thought: Gestalt (early 1900s) ○ Perception Based Theory: need to consider both structure and function to understand the mind “Whole is greater than the sum of the parts” ○ Max Werthheimer (1880-1943) Interested in how we perceive motion Participants shown 2 lights that flashed quickly on a screen, one after the other. When time between flashed was relatively long the participants could recognize the sequence of flashing; but when time was reduced to 1/5th of a second, participants reported single light was moving back and forth Illusory Motion: occurs because our mind has theories about how the world works, uses theories to make sense of incoming data ○ Physical stimuli = part of perceptual experience, whole is more than sum of its parts ○ Approach to psych that emphasizes the way in which the mind creates perceptual experience ○ Frederic Bartlett (1886-1969) Asked people to read and recall stores after varying periods of time When he analyzed their errors he found participants often remembered what they expected to read rather than what they actually had Developmental Psychology ○ Study of the ways in which psychological phenomena change over the life span ○ Jean Piaget (1896-1980) Trying to understand minds of children, often by examining mistakes they made Mind has theories about the world works and because small children haven’t learned these theories they see the world in a fundamentally different way than adults do ○ Studying people’s perceptions, memories, judgements Schools of Thought: Ecological Psych ○ More modern descendent of functionalism and gestalt psych is ecological psych which was shaped particularly by JJ Gibson (1904-1979) ○ Argued out perceptual systems prioritize information that allows us to act Schools of Thought: Behaviorism ○ Argued that introspection was subjective and unreliable; psychologists should restrict themselves to objectively observable behavior  ○ Behaviorism: approach to psych that restricts scientific inquiry to observable behavior ○ John Watson (1878-1958) Behaviorists focused on training and learning Psych should be study only between stimulus and response “Anyone, regardless of nature, can be trained to be anything” Nature side of nurture vs. nature wanted to understand the acquisition of complex human emotions like fear Little Albert Experiment Before rat equaled neutral stimulus Shows the infant white rat and shows that they’re completely fine with it (neutral stimulus) Then he puts the rat out and at the same time plays a loud scary noise (turning rat into conditioned stimuli) Rat now instills fear in little albert b/c of the noise (unconditioned stimulus) Convinced people of behaviorism, shifted experimental psychology completely ○ Pavlov (1849-1936) Dogs and conditioning them to salivate Stimulus + unconditioned response = conditioned response Watson learned from his research ○ B.F Skinner: Operant Conditioning 1904-1990 Skinner box with rats and pigeons, identified principles of reinforcement Cage had a lever that when pressed delivered food thru a tube Recorded the number of times the rat pressed the lever At first rats, accidentally bumped into lever, and after a few happy accidents they began to learn that pressing the lever meant food ○ Learned to operate environment to produce food When behavior produced food the rats would repeat it → reinforcement Principle of Reinforcement: behavior that is rewarded will be repeated and any behavior that isn’t rewarded won’t be repeated Consequences of behavior determine whether it is more likely (reinforcement), or less likely (punishment), to occur again Implications on our free will → skinner claimed it was an illusion and that the world could solve all social issues by addressing that behavior is nothing more than the sum of its consequences Moving away from behaviorism ○ Psychologists began to find behaviorism oppressive ○ Scientists at the time supposed nothing was real unless you could prove it with a rat  Internal states, consciousness, feelings all off-limits Problem: not all info is equally learn-able Rats can associate a new taste with sickness, but struggle to learn the same association with light Need for some evolutionary explanation ○ Chomsky found operant conditioning an inadequate explanation of language learning (1959) Young children easily generate novel sentences Children are not conditioned into using good grammar Cognitive Revolution ○ Cognitive neuroscience: Study of relationship between the brain and the mind ○ Behavioral neuroscience: study of relationship between brain and behavior ○ Study of human information processing ○ During WW2 the military needed help understanding the human interface with tech ○ With tech on the rise, psychologists wondered if they could be made to think ○ Computer’s observable behavior is similar to a rats If brain is hardware mind is software ○ Donald Broadbent (1926-1993): discovered attention has a limited capacity ○ George Miller (1920-2012): found consistency in capacity limits in memory 1950s – computing metaphors for the mind ○ Wilder Penfield (1891-1976) Neurosurgeon treating epilepsy thru cortical ablation Montreal procedure: treating seizures with surgical removal of brain tissue Electrical stimulation of the cortex to identify seizure foci Stimulated brains of awake patients during surgery Allowed him to discover how different parts of brain support different mental functions and behaviors Laid out maps of sensory and motor function in specific areas of the cortex Supports LOF ○ Neuroimaging PET (1980s) uses radioactivity MRI (1990s) to show both structure and function in brain ○ Donald Hebb (1904-1985) Studied effects on the development of vision in rats that were being reared in darkness Worked with Penfield Theory on neural basis of learning ○ Brenda Milner (1918-) Discovery of the brain basis of long term memory Psychoanalysis ○ Jean Martin Charcot (1825-1893) + Pierre Janet (1859-1947)  Became interested in patients with odd collection of symptoms with no obvious physical illness or injury When patients were hypnotized their symptoms disappeared, but when they emerged from hypnotic trance the symptoms returned Hysteria: loss of function with no obvious physical origin ○ Sigmeund Freud (1856-1939) Treating patients with hysteria and other nervous disorders Suspected many of them has painful childhood experiences they couldn’t allow themselves to remember Memories had been relegated to unconscious Part of the mind that contains info of which people are unaware Repressed memories were supposed source of hysterical symptoms Created psychoanalytic theory: emphasizes influence of unconscious on feelings, thoughts and behaviors Saw mind as set of processes that are largely hidden from our view Psychoanalysis: therapy that aims to give people insight into contents of their unconscious minds Asked patients about dreams and free associations Little impact on some, big impact on others Social Psychology ○ Study of the causes and consequences of sociality ○ Kurt Lewin (1890-1947) Behavior is not a function of the environment, but of the person’s subjective construal of the environment Responses do not depend on stimuli, but on how people think about those stimuli ○ Solomon Asch (1907-1996) Told one group good traits to bad traits of a man, and another group the same traits but in the opposite order People who heard good traits first liked him more Primary Effect Evolutionary Psychology ○ John Garcia (1917-2012) Studying how rats react to radiation sickness Noticed rats instantly learned to associate their nausea with the taste of the food they ate just before getting sick, instantly developed aversion to it Rats could not learn to associate their nausea with flashing light/sound of a buzzer Hypothesized every organism is evolved to respond to particular stimuli in particular ways → animals come into world biological prepared to learn some associations more easily than others Rats learned nausea from food more quickly because evolutionarily that is most likely why they would have gotten sick in the wild  ○ Study of the ways in which the human mind has been shaped by natural selection Cultural Psychology: ○ Culture = values traditions, beliefs shared by a particular group of people ○ Became popular with rise of behaviorism ○ : study of how culture influences mental life ○ Masuda and Nisbett 2001 American and Japanese participants were shown drawings that differed in small details, and were then asked to point out the differences Americans detected more differences in foreground objects Japanese detected more differences in background objects Westerners tend to process visual info analytically whereas Easterners do so holistically In 1892 Wiliam James and 6 other American psychologists formed an organized representing psych profession → APA (American Psychological Association) Unit 2 Louise Hay ○ Everything that happens to people is a result of the thoughts they choose to think ○ Claimed she had been diagnosed with incurable cancer but cured herself by changing the way she thought ○ Didn’t believe in scientific evidence, just her “inner ding” Scientists have developed tools for determining whether claims are right/wrong Empiricism: How to Know Stuff ○ Dogmatists: thought the best way to understand illness was to develop theories of the body’s functions ○ Empiricists: thought best way to understand illness was to examine sick people ○ People who went to dogmatists tended to die a lot, gaining it the meaning of clinging to one’s beliefs ○ Empiricism now means describes the conviction that accurate knowledge of the world can be acquired by observing it Scientific Method ○ Procedure for using empirical evidence to establish facts (empiricism is backbone) ○ When we have no idea about how something in the world works, we must go out into the world, make observations, and then use them to determine whether the idea is true Ideas = theories = explanation for natural phenomena ○ Good theory makes specific predictions about what’s to be observed if theory is true ○ Should statement in theory = hypothesis = falsifiable prediction made by theory ○ Theory can never be proved right Will not ever be sure about everything that has an will exist  Only observe a small population of targeted object/group Observations consistent with theory can increase our confidence but never make us 100% confident that it’s right ○ Only way to learn truth about the world is to 1. Develop a theory 2. Derive a falsifiable hypothesis from it 3. Test that hypothesis by observing world (gathering empirical evidence) Empirical Method is needed as observation thru human visual field isn’t enough ○ method : tech that enhance power of senses ○ Human behavior is easy to see, but 3 qualities keep it from being simple Human beings are complex People are extremely variable People are extremely reactive People tend to act differently when they think they’re being observed Psychologists have developed methods of observation (discover what people do) and methods of explanation (discover why people do it) Measurement ○ Must define what we want to measure ○ Must find a way to detect it Operational Definition: description of a property in measurable terms ○ Happiness = one’s dopamine levels/ # of times they smile in an hour/ how happy they say they are Define the property ○ Generation an operational definition that has construct validity Detect the Property ○ Design an instrument that has reliability and power Construct Validity: feature of operational definitions whose specified operations are generally considered good indicators of the specified properties ○ Definition has validity when most beholders agree that it is an indicator of the property 2 key features of a good detector ○ Power: director’s ability to detect the presence of differences or changes in magnitude of a property (detecting difs when they exist) ○ Reliability: detector’s ability to detect absence of differences or changes in magnitude of a property (not detecting difs when they don’t exist) Demand Characteristics: doing what is expected ○ Aspects of an observational setting that cause people to behave as they think someone else wants or expects Naturalistic Observation: ○ technique for gathering information by unobtrusively observing people in their natural environments Privacy and Control  ○ People are less likely to be influenced by demand characteristics when given anonymity (taken advantage of in studies) Unawareness ○ Make participants unaware of purpose of observation ○ They can’t try to behave as they should if they don’t know the should ○ Why psychologists sometimes mislead people (by giving them pointless tasks or asking pointless questions) Observer Bias: ○ Tendency for observer’s expectations to influence both what they believe they observed and what they actually observed ○ (Rosenthal & Fode 1963) two groups, (1) told rat was fast learner, (2) told rat was slow learner, and after watching it solve maze the participants reported measuring speed as 2.35 minutes and 3.47 minutes ○ Expectations can influence observations ○ Expectations can influence reality Double Blind Study ○ Study in which neither the researcher nor the participant knows how the participants are expected to behave Description ○ Psychs rarely study entire population Population = complete collection of people ○ Tend to measure properties of a sample Sample = partial collection of people drawn from a population Frequency Distribution ○ Graph showing number of times that the measurement of a property takes on each of its possible values ○ Positively skewed (lean to left), negatively skewed (lean to right) ○ Normal distribution (bell curve): math defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions Synchronized patterns of variation ○ Measuring a pair of variables Variables: properties that can have more than 1 value ○ Made series of measurements rather than just 1 ○ Pattern of variation → correlation Correlation coefficient: measure of direction and strength of a correlation ○ Natural correlation: correlation observed in natural world Third Variable Problem: (Correlation is not Causation) ○ Refers to the fact that the natural correlation between 2 variables cannot be taken as evidence of a casual relationship between them because a third variable might be causing them both Experimentation: Establishing Causation ○ Experimentation: technique for establishing causal relationship between 2 variables  ○ Only 3 possible natural correlations X→Y Y→X Z→X&Y ○ If we can eliminate 2 of the above we know which one is real ○ Eliminate using manipulation and random assignment Manipulation: Making Different Conditions ○ Technique for determining causal power of a variable by actively changing its value Experiments require manipulation of one variable ○ Conditions of experiment: dif environments/groups people are placed in to separate experimental experiences Self selection: problem that occurs when anything about a participant determines the value of the independent variable to which the participant was exposed P-Value: ○ If P <.05 results are statistically significant Internal Validity: attribute of an experiment that allows it to establish causal relationships ○ When it’s high in internal validity everything inside experiment is working as it should in order for us to be able to draw causal conclusions from the results ○ We can only draw conclusions on likeliness and not 100% casualty External Validity: attribute of an experiment in which variables have been operationally defined in a representative way ○ Representative of the real world ○ Most experiments are externally invalid Case Method: procedure for gathering scientific info by studying a single individual Random sampling: technique for selecting participants that ensures that every member of a population has an equal chance of being included in the sample ○ Representative of population Replication ○ Experiment that uses same procedures as a previous experiment but with a new sample from the same population ○ Replication crisis is somewhat overblown by bad replications Errors (flukes and flunks) ○ Type 1 Error When researchers conclude that there is a causal relationship between 2 variables when in fact there is not ○ Type 2 Error When researchers conclude that there is not a causal relationship between 2 variables when in fact there is ○ Anything you do to reduce the likelihood of one increases likelihood of the other ○ No one knows the expected level of non-replicability in a healthy science Sir Francis Bacon 1620 ○ Created confirmation bias  ○ Published book describing method of discovering facts about natural world which turned into scientific method ○ We see what we expect and want to see When 2 people look at same evidence they Once humans have adopted opinions, our understanding draws everything else to support and agree with them Beliefs distort our view of new evidence ○ Darley and Gross 1983 Had participants watch video of a little girl named Hannah reading and were asked to rate it People in group told Hannah was richer rated her performance higher, people in group told she was poorer rated her performance lower Even used evidence from videos to support their claims ○ Views also distorted by preferences, prejudices, ambitions, aversions, hopes, needs, wants and dreams ○ Lord et al. 1979 Participants shown effectiveness of death penalty in preventing crime (some evidence supported it, some didn’t) Participants who had previously supported the death penalty became even more supportive, and participants who had previously opposed it became eve more opposed ○ Hold different evidence to different standards ○ Influence which evidence we consider in the first place Surround ourselves with people who hold similar beliefs When searching for evidence, it’s generally to support previous beliefs Once they find it they tend to stop looking ○ Doubt your own conclusions! ○ Don’t Consider What We don’t see Bacon claimed people rarely pay attention to what is missing Much easier to think about what is there than what isn’t Newman et al 1980 Had trigrams, asked people to figure out patterns Group where pattern was existence of letter T tended to figure it out on 34th trial, where group where pattern was absence of letter T never figured it out Skeptical stance ○ Scientists actively seek to discover and remedy their mistakes Respecting People ○ Nuremberg Code of 1947 and Declaration of Helsinki in 1964 Laid out ethical treatment of people who participate in experiments ○ 1. Research should show respect for persons and their right to make decisions for and about themselves without undue influence or coercion ○ 2. Research should show concern for welfare (maximize benefits, reduce risks)  ○ 3. Research should be just (distribute benefits and risks equally to participants without prejudice towards particular individuals or groups) APA Code Basics ○ Informed consent: verbal agreement to participate in a study made by an adult who has been informed of all the risks that participation may entail ○ Freedom from coercion: psychologists may no coerce participation Includes monetary coercion (can’t give large amounts of money for things they otherwise may decline doing) ○ Protection From Harm: must take every possible precaution to protect participants from physical or psychological harm ○ Risk-Benefit Analysis: participants may only be asked to accept small risks can’t be greater than risk they would take in everyday lives ○ Deception: may only use when it’s justified by the study’s value or when alternative procedures aren’t feasible Can’t deceive over things that may cause harm ○ Debriefing: if participant is deceived in any way they psychologist must afterwards provide them with a debriefing Verbal description of the true nature and purpose of the study ○ Confidentiality: obligated to keep private and personal info obtained Psychologist may only conduct study after REB has reviewed it ○ REB = ethics boards Respecting Animals ○ CCAC (Canadian Council of Animal Care) responsible for establishing standards for ethical use and care of animals in research Three Rs tenet ○ Replacement Researchers have to prove there is no alternative to using animals and use of animals is justified by the scientific or clinical value of the study ○ Reduction Researchers must use smallest number of animals possible to achieve the research ○ Refinement Procedures must be modified to minimize discomfort, infection, illness, and pain of animals Animals need be treated humanely with comfortable housing and ability to satisfy basic instincts Respecting Truth ○ Once data is collection no one ensures it is honestly analyzed and thoroughly reported ○ Psychology works on the honor system and community enterprise Replications can show the validity of other research/studies ○ Psychologists must Report truthfully on what they did and what they found Can’t fabricate results  Can’t mislead by omission Share credit fairly by including as coauthors of their reports the other people who contributed to the work As well as mentioning their reports and the other scientists who have done related work Share their data APA says ethical psychologists do not withhold data 9/17 Theory: an attempt to explain natural phenomena (good theory generates testable predictions) Hypothesis: a specific (and falsifiable) prediction made by a theory Rule of Parsimony: simplest theory that explains all the evidence is the best one Psychometrics: ○ Power: sensitivity to detect small changes ○ Reliability: tendency to produce same result consistently ○ Validity: extent to which a measurement and a property are conceptually related (does your measure, measure what you think it does?) Measures ○ Define the property: generation and operational definition that has construct validity ○ Detect the property: design instrument that has reliability and power Experiment: Measuring Aggression ○ Three buttons: steal money from opponent, protect money, or make more money ○ Unseen opponent will at some point steal money from adolescent → provokes ○ Watch to see how participant responds to the provocation ○ Try to triangulate using other data Common research designs in Psych ○ Single cases studies (in neuropsychology) Ex: patient tan and Broca’s area ○ Correlational study (often questionnaires) ○ Naturalistic Observation Ex: walking speed in dif cities ○ Experiments 1. Manipulation: experimentally change something Independent and dependent variables Control group 2. Sampling Random assignment (avoid self selection) Controlling for important subject variables (confounds) Convenience samples: students are WEIRD (western, educated, industrialized, rich, democratic)  Expectations and Biases ○ Hawthorne Effect: participant performance changes when they feel watched ○ Demand Characteristics: participants behave as they think they should To avoid it: Use covert measures Use deception (and debrief after study) ○ Observer bias: we interpret data to match our expectations To avoid Use double-blind designs Standardize data analysis Stats and Psych ○ Collection, organization and interpretation of data Why use stats? ○ Summarize and organize sampled data (descriptive stats) ○ Interpret whether differences in our sampled data are (likely to be) meaningful (inferential stats) Descriptive stats ○ Measures of central tendency Mean, median, mode, outliers, range, standard deviation ○ Normal distribution 9/19 Histograms: plot frequency distribution (count #s on x-axis) If x and y are correlated then there are at least 3 possible explanations ○ X causes Y ○ Y causes X ○ Z (3rd factor) causes X and Y Inferential stats: ○ If sample is representative of the population, our results may generalize from the sample population ○ To determine whether difference between groups is meaningful, need to use inferential stats ○ 3 factors More people reduces likelihood that sample is uncharacteristic of pop Variability between groups bigger difs between groups may reflect a stronger effect of your manipulation Variability within each group High variability reduces potential differences between groups Ethics Nazis and medical research (1940s) caused wide outcry ○ Were doing highly unethical experiments on prisoners ○ Called for international code of ethics Nuremberg Code (1947)  ○ Informed consent ○ human research based on animal work ○ Benefits > risks ○ Minimize discomfort and avoid injury ○ *specific to medical research Tuskegee Syphilis Study (1932-1972) ○ When study began there was no treatment for syphilis ○ Wanted to study how the disease progressed in people ○ Study of 600 people - most were low income black men ○ When recruiting for study they used language subjects were used to - weren’t told they were getting syphilis ○ Not all of them understood it was research and not medical care ○ Invasive and harmful procedures (many received spinal taps) ○ In the 40s penicillin became available, treats syphilis ○ Withheld treatments from participants which led to preventable deaths ○ Many of these men gave syphilis to their partners which led to children also being born with syphilis ○ Lack of informed consent, deeption, withholding care and info, exploitation of a vulnerable group ○ After wide outcry they decide nuremberg code wasn’t detailed enough Belmont Principles (1979) ○ Beneficence (welfare) - do no harm, benefits must outweigh risks ○ Respect for People - respect for autonomy, need for informed consent ○ Justice - equality in participation in research process, avoiding exploitation of vulnerable groups Milner Obedience Experiment (!!!!!!!!) ○ Motivated by Nazi Germany’s behavior ○ Advertised as a learning experiment ○ Higher shocks when learner makes errors ○ How far will people go to obey authority? ○ Issues Deception Unanticipated psychological harm 9/24 Stanford Prison Experiment - Zimbardo (1973) ○ How do roles put upon us influence our behavior ○ Independent variable: role (prisoner/guard) ○ Dependent variable: behavior ○ All men, many of them know each other, recruits them as a group, half are prisoners, half guards, live together in basement set up as mock prison ○ Guards quickly start adopting to their roles Refer to prisoners by numbers  Create punishments for them (including humiliation) ○ Prisoners also start adapting to roles Trying to escape and rebel ○ 4 people want to leave very soon after, but Zimbardo (who takes on role as chief) denies them ○ John Wayne - guard who begins to be more extreme - decided he would be worst prison guard he could possibly be Fascinated that people were believing it, wanted to see how far he could take it before someone would say stop ○ Prisoners were made to do simple things such as pushups, but the prisoners began rebelling against them ○ Guards began to see prisoners behavior as a push back against their authority John Wayne says zimbardo is authority and he’s not stopping me ○ First rebellion - prisoners barricaded themselves in cells, took of their numbers, cursing guards to their face Guards began to think of them as dangerous prisoners ○ SPE is wildly unethical now Harm done to subjects Lack of neutrality as a researcher Research Ethics Boards ○ Study justification, protocol, full study materials (consent form, ads, protocols) are reviewed by expert panel ○ Any changes must be approved and renewed annually ○ In Canada, all members of research tem must have TCPS2 training Animal Research: (divisive issue) ○ Only acceptable if and only if Discomfort and stress are minimized There are benefits to humans and animals Alternative procedures are unavailable (comp models, cell cultures, etc) Must be conducted by trained scientists ○ 91% of NIH animal research uses mice and rats ○ Increasing use of zebrafish and fruit flies ○ Majority of studies (70%) involve none/minor/short-term discomfort Three R’s ○ Reduction: reduce number of animals used in experiments as much as possible ○ Refinement: improve the way that animals are cared for and reduce pain/suffering ○ Replacement: replace experiments on animals with alternative techniques Reproducibility project ○ Attempted to replicate 100 dif papers from 2008 in 3 leading journals ○ Only 36% replicated usually with smaller effects Changing Practices ○ Inconsistent methods/lack of transparency ○ HARking - Hypothesizing after the results are known  ○ Publication Bias: harder to publish null results Neurons = very diverse, very dif shapes, sizes, functions (very specialized) Simple neuron ○ Dendrites: receive info ○ Cell body: manage the cell (contains nucleus) ○ Axon: transmits signal ○ Myelin sheath: insulate axon ○ Nodes of ranvier: gaps in myelin ○ Terminal buttons: form synapses, output signal Sensory n: receive sensory stimuli from environ Motor n: relay movement commands Interneurons: connect ns to one another; integrate and process signals Synapse: two neurons are arranged with a tiny gap = synaptic cleft ○ Pre synaptic and postsynaptic neuron ○ Often terminal button of presynaptic neuron + dendrite of post synaptic neuron Glia: outnumber neurons in the brain ○ Neurons are electrically active, and glia are all the other ones (10:1) ○ Support cells Insulate, feed, protect neurons ○ Have resting membrane potential but no action potential Types of Glia ○ Astrocytes: maintain the blood brain barrier, stabilize neurons Need blood to supply nutrients and remove waste, but it needs to be tightly controlled by blood vessels, which are wrapped by astrocytes ○ Oligodendrocytes: myelinates many neurons in the brain One provides many axons ○ Schwann Cells Many cells myelinate 1 individual neuron outside of the brain Only wraps part of it Multiple Sclerosis ○ Immune system attacks the myelin ○ Impairs neural transmission ○ Results in pain and motor impairments ○ Exemplifies importance of myelin ○ Argument over whether problem is starting in the myelin or in the immune system Resting potential: at rest charges are unequal inside and outside n. Charge across membrane is -70mv ○ Outside → excess sodium, inside → excess potassium Unit 3: Neuroscience and Behavior Steve Mantador ○ Hockey player with tons of brain injuries ○ Chronic traumatic encephalopathy: form of progressive brain damage that has been linked to repeated concussions ○ Struggled with memory loss, sleep changes, mood changes, depression ○ Awareness of condition was heightened by movie - Concussion ○ Scientists are actively debating effects of CTE Estimated 86 billion neurons in our brains ○ All thoughts, feelings, behaviors spring from these cells that take in info and produce some output a trillion times a day Neurons: cells in the nervous system that communicate with each other to perform information processing tasks Santiago Ramon y Cajal (1852-1934) ○ Learned about new technique for staining neurons in the brain (golgi staining) ○ Stain highlighted appearance of entire cells, revealing they came in dif shapes and sizes ○ Discovered that neurons are complex structures composed of three basic parts Cell body Largest component of the neuron that coordinates the info processing tasks and keeps the cell alive Where protein synthesis, energy production, metabolism take place Contains a nucleus: houses chromos which contain DNA Enclosed by a porous membrane that allows some molecules to flow into and out of the cell Dendrites Receive info from other neurons and relay it to cell body Comes from greek work: tree, cause they look like tree branches Axon Carries info to other neurons, muscles, glands Can be very long: up to meter from base of spinal cord down to big toe In many neurons, axon is covered by myelin sheath ○ Myelin sheath: Insulating layer of fatty material ○ Made of Glial Cells - support cells found in the nervous system Serve variety of roles Some digest parts of dead neurons Others provide physical/nutritional support Others form myelin and help them carry info more efficiently ○ Neurons have two types of specialized extensions of cell membrane that allow them to communicate (axons and dendrites)  ○ Neuron Doctrine: nervous system is made up of individual cells ○ Observed that axons and and dendrites don’t actually touch each other ○ Small gap = synapse = junction/region between axon of 1 neuron and dendrites/cell body of another ○ Many neurons have a few thousand synaptic junctions so adults have trillions of synapses ○ Transmission of info across synapse is fundamental to communication between neurons, allowing us to think, feel, and behave 3 major types of neurons ○ Sensory: receive info from external world and convey it to the brain via the spinal cord Specialized endings on dendrites that receive signals for light, sound, touch, taste smell ○ Motor: carry signals from spinal cord to the muscles to produce movement Often have long axons that reach to muscles at our extremities ○ Interneurons: connect sensory, motor, other interneurons Most of nervous system is composed of them Carry info from sensory n to nervous system to motor n Perform variety of information processing functions within nervous system Work together in small circuits to perform simple tasks (ex: locating sensory signal), and complicated ones (ex: recognizing face) Neurons specialized by location ○ Purkinje cells: type of interneuron that carries info from cerebellum to the rest of the brain and spinal cord ○ Pyramidal cells: found in cerebral cortex, have triangular cell body and a single long dendrite among many smaller ones ○ Bipolar cells: type of sensory neuron found in the retinas of the eye, have a single axon and single dendrite ○ Brain processes dif types of info, so a substantial amount of specialization at the cellular level has evolved to handle these tasks Neuromyths ○ Only use 10% of our brains ○ Environments rich in stimuli improve brains of preschool children ○ Individuals learn better when they receive info in their preferred learning style ○ 47% of teachers believed the first myth, 76% believe the second, 94% of the third 3.2 Electrochemical actions of neurons: info processing Neurons use electrical and chemicals signals to communicate ○ Electric signal is conducted inside the neuron, from dendrites to cell body, then down the axon ○ Then chemical signal is transmitted from one neuron to another, across synapse Electric Signaling: Conducting info inside a neuron ○ Cell membrane has small pore that act as channels to allow ions to flow into and out of cell ○ Ions: atoms or molecules that carry a small positive or negative electric charge  Resting Potential ○ When neuron is at rest some sions, such as potassium ions (k+) and negatively charged protein ions (A-) are more abundant inside the neuron than outside in the fluid filled space between neurons ○ Other ions such as sodium (Na+) are more abundant outside the neuron ○ Inside of neuron has a slight negative electric charge ○ Small imbalance = resting charge = difference in electric charge between the inside and outside of a neuron’s cell membrane ○ Axon is usually around -70 millivolts (1930s) ○ Reason for difference in concentrations is that special channels in the cell membrane restrict movement of ions in/out of cell Allowing ions to rush across the membrane in a fraction of a second Action potential: sending signals across the neuron ○ Action potential: electrical signal that is conducted along length of a neuron’s axon to a synapse ○ Only occurs when electric shock reaches a certain level ○ Above that threshold increases in the electric shock did not increase strength of the action potential ○ Action potential is all or none Electric stimulation below threshold fails to produce an action potential, whereas electric stimulation above threshold always produces action potential and always at the same strength ○ Neuron “fires” Action Potential Moves across the neuron in a domino effect ○ Action potential occurs due to changes in axon’s membrane channels ○ During resting potential membrane channels for sodium ions are closed ○ When neuron fires , sodium channels in that area of the cell membrane open up, and sodium ions rush in almost instantaneously Goes from -70 millivolts to +40 in less than 1 millisecond ○ This starts a domino effect; as sodium ions rush in, they spread inside the cell, increasing electric charge in neighboring areas → when electric charge in those areas reaches threshold channels in the adjacent cell membrane open and let in more sodium ions, spreading charge even further → influx of sodium ions triggers nearby channels to open → process repeats down entire axon ○ Conduction of action potential is greatly increased by presence of myelin sheath around the axon Myelin sheath prevents electric current from leaking out of axon Myelin doesn’t cover entire axon, clumps around them with little break points between clumps Nodes of Ranvier: current jumps from node to node quickly Process = saltatory conduction ○ Helps speed the flow of info down the axon  ○ Action potential always spreads onward (never backward) b/c sodium channels in each region of the axon are temporarily inactivated after the action potential passes over them Brief period of inactivation = Refractory Period = time following an action potential during which a new action potential cannot be initiated ○ During period electrical and chemical balance of neuron is restored To restore electrical balance, sodium channels inactivate themselves for several milliseconds stopping the inrush of sodium ions Potassium channels open, allowing excess potassium ions in the cell to escape Rapid exit of K ions returns electrical charge of membrane to a negative state To restore chemical balance, a series of specials channels (ion pumps), work to redistribute the ions until concentrations are rebalanced and resting potential is restored Chemical Signaling: Transmission Between Neurons ○ When action potential reaches end of axon it takes on a form that crosses the synaptic cleft ○ N only has one axon, but axon can have hundreds/thousands of branches Terminal buttons = knoblike structures that branch out from an axon Each terminal button has neurotransmitters = chemicals that transmit info across synapse and initiate/prevent new electric signal ○ Action pot in presynaptic neuron travels down length of axon to terminal buttons where stimulates the release of nts from vesicles into the synapses ○ Nts quickly float across cleft and bind to receptor sites on nearby dendrite of postsynaptic n ○ = synaptic transmission ○ When post synaptic n receives nt it may activate nearby channel, which can raise/lower voltage across membrane ○ Depending on timing + voltage inside cell body memb may reach the threshold and trigger a new action pot ○ Nts chemical messages create electrical signal, neuronal communication continues Ns tend to form pathways in the brain that are characterized by specific types of nts ○ 1 nt may be prevalent in 1 part of the brain, and 1 may be prevalent in another ○ Nts and receptor sites act like lock and key system Some nts bind to specific receptor sites on a dendrite Nts leave synapse thru 3 processes ○ Reuptake: nts are absorbed into terminal buttons of presynpatic neuron’s axon or by neighboring glial cells ○ Enzyme Deactivation: can be destroyed by enzymes in synapse, specific enzs break down specific nts ○ Diffusion: nts drift out of synapse, can no longer reach receptors  Nts can bind to receptor sites on pres n = autoreceptors, which detect how much of a nt has been released into a synapse and may stop the release of more Types/Function of NTs ○ Acetylcholine: involved in a # of functions, including voluntary motor control Found in n of brain, synapses where axons connect to muscles + body organs Activates muscle movements, contributes to regulation of attention, learning, sleeping, dreaming, memory Alzheimer’s is associated with deterioration of ACh producing ns ○ Dopamine: regulates motor behavior, motivation, pleasure, emotional arousal Plays a role in drug addiction High levels of dopamine in some pathways are linked to schizophrenia Low levels linked to Parkinson’s ○ Glutamate: major excitatory nt → enhances transmission of info between ns GABA = primary inhibitory nt in brain Tends to prevent firing of ns Too much glutamate/too little gaba can cause ns to become overactive, causing seizures ○ Influence mood/arousal Norepinephrine: state of vigilance, heightened awareness of dangers in environment Serotonin: regulation of sleep/wakefulness, eating, aggressive behaviors Low levels of each are implicated in mood disorders ○ Endorphins: chems that act within pain pathways + emotion centers of brain Contraction of endogenous morphine Morphine: Drug that has intensely pleasurable + pain relieving effect Internally produced substance that has similar but less intense properties Dulling experience of pain and elevating moods Nts involve balance ○ Slight imbalance can dramatically affect behavior ○ Sometimes brain causes imbalance, other times behavior does Behaviors: smoking, taking drugs, drinking Drugs Mimic NTs ○ Many drugs that affect the nervous system operate by increasing /interfering/ mimicking manufacture/function of nts ○ Agonists: drugs that increase action of nt ○ Antagonist: drugs that diminish the function of a nt ○ Some drugs alter a step in the production/release of the nt, others have chemical structure similar to nt so drug is able to bind to that nt’s receptor L-dopa, made from dopamine, used to treated Parkinson’s Agonist that elevates dopamine by increasing its production ○ Amphetamine: popular drug that stims the release of norepinephrine + dopamine, blocks their reuptake  Combo creates an excess of nts that flood the synapse, activating receptors over and over Cocaine also blocks reuptake Agonists Norepinephrine and dopamine play critical role in mood control such that increase in either results in euphoria, wakefulness, burst of energy Nore also increase heart rate Overdose can cause heart to contract so rapidly that heartbeats do not last long enough to pump blood effectively ○ Opioids: class of chemically similar drugs either derived naturally from opium poppy (morphine, heroine) or made synthetically (oxycodone, hydrocone, fentanyl) Work in part by acting as agonists for endorphins Feelings of calm and euphoria Highly effective antagonists that decrease release of nts involved in perception of pain Widely prescribed for pain relief Diminish brainstem’s sensitivity to rising levels of co2 in the blood, depressing breathing In overdose this leads to asphyxiation/death Opioid crisis in Canada (19 deaths a day) Naloxone: opioid that acts as an antagonist Binds with opioid receptors, blocking agonists and preventing their effects of neurons ○ Prozac: antidepressant, agonist that blocks reuptake of serotonin, SSRI ○ Propranolol: in a class of drugs called beta blockers Obstruct receptor sites in the heart for norepinephrine, a nt that increases heartbeat Nore cannot bind to these receptors, so the heart rate slows Organization of the Nervous System Neurons work by forming circuits and pathways in the brain Nervous system: interacting network of neurons that conveys electrochemical information throughout the body ○ Neuroscience: study of the nervous system 2 major divisions of the nervous system ○ Central Nervous System Composed of the brain and spinal cord Receives sensory info from external word, processes and coordinates info, sends commands to skeletal/muscular systems for action At top of CNS is the brain = contains structures that support most complex perceptual, motor, emotional, cognitive functions of nervous system Spinal cord branches down from brain  Nerves that process sensory info and relay commands to body connect to the spinal cord ○ Peripheral Nervous System Connects central nervous system to body’s organs and muscles Composed of 2 major subdivisions Somatic: set of nerves that conveys info between skeletal muscles and CNS ○ Humans have conscious control over it ○ Motor n: carry instructions from CNS to muscles - efferent (out of) ○ Sensory n: carry sensory info into CNS - afferent (into) Autonomic: set of nerves that carries involuntary and automatic commands that control blood vessels, body organs, glands ○ Works on its own to regulate bodily systems ○ 2 subdivisions: Sympathetic: set of nerves that prepares body for action in challenging/threatening situations Ex: dilates pupils to let in more light, increases heart rate + respiration to pump more O to muscles, diverts blood flow to brain and muscles, activates sweat glands to cool body, inhibits salivation+bowel movements to save energy, suppresses body’s immune responses, suppresses responses to pain/injury Increase likelihood of escape Parasympathetic: Helps body return to normal resting state Reverses effects of SNS Ex: constricts pupils, slows heart rate/respiration, diverts blood flow to digestive system, decreases activity in sweat glands ○ 2 systems coordinate to control many bodily functions Ex: sexual behavior In men PNS engorges blood vessels of penis to produce erection, but SNS is responsible for ejaculation In women PNS produces vaginal lubrication, but SNS underlies orgasm Anxiety can lead to sympathetic nervous system activated leading to premature ejaculation Components of CNS  ○ Spinal cord needed for important tasks that keep you breathing, responding to pain, moving your muscles, walking For some basic behaviors, spinal cord doesn’t need any input from brain Connections between sensory inputs and motor ns in spinal cord mediate spinal reflexes - simple pathways in ns that rapidly generate muscle contractions Reflex arc = neural pathway that controls reflex actions ○ More elaborate tasks require the brain and spinal cord PNS sends message from sensory n thru spinal cord into brain Brain sends command for voluntary movement thru spinal cord to motor n (whose axons project out skeletal muscles) ○ Damage to spinal cord severs connection from brain to sensory and motor n that are essential to perception and movement Location of injury often determines extent of abilities that are lost ○ Dif regions of spinal cord control dif systems of the body Individuals with damage at a particular level of spinal cord lose sensations of touch and pain in body parts below the level of the injury (also lose motor control over those areas) Christopher Reeve = superman actor who injured spinal cord and was paralyzed from the neck down Learning to treat them by focusing on how brain changes in response to injury Related to plasticity 3.4 Structure of the Brain Brain weighs 1300-1400g  Areas of the brain from “bottom to top”, noting dif regions are meant for dif tasks ○ Simpler functions performed at lower levels, and higher functions at higher levels Side by side fashion ○ Two sides are roughly symmetrical but each specializes in some tasks No structure/area in the brain can act alone Individual regions within the brain are organized into large scale networks, which consist of interacting interdependent regions that work together to support complex functions Hindbrain: area of the brain that coordinates info coming into/out of spinal cord ○ “Stalk” rest of brain sits on ○ Controls most basic functions of life: respiration, alertness, motor skills ○ Medulla Extension of spinal cord into skull that coordinates heart rate, circulation, respiration Beginning inside medulla and extending upward is a small cluster of n = Reticular formation = regulates sleep, wakefulness, levels of arousal Experiment where researchers stimulated RF in sleeping cat → caused animal to awaken almost instantly + remain alert Severing connections between RF and rest of brain caused animal to go into irreversible coma Rf remains same delicate balance between alertness + unconsciousness in humans ○ Many anesthetic work by reducing activity in rf ○ Cerebellum: Large structure of the hindbrain that controls fine motor functions Latin for little brain Orchestrates proper sequence of movements and contributes to fine tuning of behavior (smoothing actions to allow for better execution) Initiation of behavior involves other areas of brain Recent research shows cerebellum does more than motor control Involved in broader range of cognitive, social, emotional functions Area of active investigation ○ Pons Structure that relays information from cerebellum to the rest of brain Latin for bridge Midbrain ○ Relatively small in humans ○ Tectum: orients an organisms to the environment Receives stimulus input from eyes, ears, skin and moves organism in coordinated way toward the stimulus ○ Tegmentum: involved in movement and arousal Also helps orient an organism towards sensory stimuli ○ Central location of neurotransmitters involved in arousal, mood, motivation, and brain structures that rely on them Forebrain  ○ Highest level of brain - controls cognitive, emotional, sensory, motor functions ○ Cerebral Cortex: outermost layer of the brain, visible to naked eye, divided into 2 hemispheres ○ Subcortical Structures: areas of the forebrain housed under cerebral cortex near center of the brain Subcortical Structures ○ Nestled into the brain where they are protected ○ Limbic System Thalamus Relays and filters info from all senses (except smell) and transmits it to cerebral cortex Relays info to a variety of locations Actively filters sensory info, giving more weight to some inputs, less weight to others Closes pathways of incoming sensations during sleep Hypothalamus Regulates body temp, metabolism, blood sugar levels, hunger, thirst, sexual behavior Lesions to parts of hypot can result in overeating, and other parts to a complete lack of appetite Messages from cerebral cortex sent to hypothalamus to trigger the release of hormones ○ Plays role in sex Electric stimulation of some areas of hypot in cats can produce hissing and biting, while other areas produce what seems to be intense pleasure ○ McGill rat study delivered electric current to rat, found when they were able to press bar to trigger their own stimulation they did it several thousands time in 1 hour Hippocampus Critical for creating new memories and integrating them into a network of knowledge so that they can be stored indefinitely in other parts of the cerebral cortex Someone with damage to h can only hold info for some seconds before they forget the info and the experience that produced it (Scoville & Milner) ○ Memory of learned habitual routines/emotional reactions remains intact Amygdala Plays central role in many emotional processes, particularly the formation of emotional memories Attaches significance to previously neutral events that are associated with fear, punishment, or reward  When in emotionally arousing situations, amygdala stimulates hippocampi to remember many details surrounding the situation Particularly involved in encoding events as fearful ○ Basal Ganglia Set of subcortical structures that directs intentional movements and plays a role in reward processing Receive input from CC and sends outputs to motor centers in brainstem Part of BG = Striatum = important role in control of posture and movement Parkinson’s damaged midbrain that normally supplies striatum with dopamine Striatum also plays role in reward processing ○ Nucleus Accumbens has been linked to various kinds of rewards (including social reward such as approval) ○ Pituitary Gland (endocrine system) Endocrine System ○ Network of glands that produce/secrete hormones into the bloodstream Horms = chemical messages that influence wide variety of functions Ex: metabolism, growth, sexual development ○ Works closely with nervous system ○ Main glands Thyroid: regulates bodily functions such as body temp + heart rate Adrenals: regulate stress responses Pancreas: controls digestion Pineal: secretes melatonin, influencing sleep-wake cycle ○ Overall functioning is orchestrated by pituitary gland PG: master gland of the body’s hormone producing system, which releases hormones that direct the functions of many other glands in the body  ○ Hypothalamus sends hormonal signals to pituitary gland which then sends them to other glands to control stress, digestive activities, and repro processes Ex: sense threat, sensory n sends signals to hypot, stimulating release of ACTH from PG, stimulating adrenal glands to release horns that activate the sympathetic nervous system ○ Plays a key role in sexual behavior and reproduction Ovaries in females which make estrogen Testes in males which make testosterone Neither hormone is exclusive to one gender Cerebral Cortex ○ Wrinkled surface you see when looking at the brain with the naked eye ○ Smooth part of surface = gyri, indentations/fissures = sulci Triumph of evolution Crumpling allows for more surface area confined in a smaller space ○ Functions of cerebral cortex can be understood at 3 levels: Separation of the cortex into 2 hemispheres Functions of each hemisphere Role of specific cortical areas Organization Across Hemispheres ○ 1st level of organization divides 2 hemispheres ○ Almost symmetrical in looks and functions ○ Contralateral Control: each hemisphere controls opposite side of the body  ○ Cerebral hemispheres are connected to each other by commissures = bundles of axons that make communication possible between parallel areas of the cortex in each half Largest = Corpus Callosum = connects large areas of cc on each side of brain, supports communication of info across hemispheres Organization Within Hemispheres ○ Distinguishes functions of dif regions within each hemisphere of the brain ○ Each hemisphere of cc divided into 4 lobes ○ Occipital Lobe: processes visual info Sensory receptors in the eyes send info to thalamus, sends info to primary areas of occipital lobe, where simple features of stimulus are extracted Features are then processed into more complex map, leading to comprehension of what’s being seen Damage to this area of brain gives at least parietal blindness, as people are able to process info but not interpret it ○ Parietal Lobe: processes info about touch Contains somatosensory cortex Strip of brain tissue running from top of brain down to the sides Each part of somatosensory cortex maps onto a particular part of the body ○ Can be illustrated as distorted figure = homunculus Body parts rendered according to how much cortex is devoted to them Different parts of motor cortex correspond to dif body parts Motor cortex initiates voluntary movements + sends messages to basal ganglia, cerebellum, spinal cord ○ Temporal Lobe: responsible for hearing and language Primary auditory cortex in temporal lobe is analogous to somatosensory cortex in parietal lobe Receives sensory info from ears based on frequencies of sounds Secondary areas of temporal lobe then process info into meaningful units (speech and words)  Also contains areas that interpret meaning of visual stimuli and help us recognize common objects in the environment ○ Frontal Lobe: specialized areas for movement, abstract thinking, planning, memory, judgment Contains motor cortex Other areas in it coordinate thought processes that help us manipulate info and retrieve memories Can use this to plan behaviors and interact with others Executive that sets us apart from most other species Organization within specific lobes (3rd level) ○ Involves representation of info within specific lobes in the cortex ○ Hierarchy of processing stages from primary areas handles fine details of info all the way up to association areas Association areas: composed of ns that help provide sense and meaning to info registered in the cortex Ex: ns in primary visual cortex are highly specialized Some detect horizontal orientation, others movement, others info about human vs nonhuman forms Association areas interpret info extracted by primary areas to make sense of what’s being perceived Ex: ns in primary auditory cortex register sound frequencies but it’s the as of temporal lobe that allow us to understand them ○ Mirror Neurons: active when an animal performs a behavior, and when another animal observes that animal performing the same behavior Found in the frontal + parietal lobe Been found in birds, monkeys, humans More highly activated when watching a behavior with a purpose Seem to be related to recognizing the goal someone has in carrying out an action + the outcome of that action Controversy interpretation of mirror n in humans Some researchers claim impairment to motor n contribute to difficulties with understand other people (as in autism) ○ Neurons in association areas are usually less specialized + more flexible than neurons in primary areas Can be shaped by learning/experience to do job more effectively Brain Plasticity ○ Sensory cortices are not fixed ○ Can adapt to changes in sensory inputs → plasticity Ex: if you lose finger in accident, the somatosensory area that represents that figure is initially unresponsive (no sensory input going into that part of the brain), but it eventually becomes responsive to stimuli of fingers adjacent to the missing one ○ Functions of brain areas can be reassigned to accommodate changing input from the environment  ○ Suggests sensory inputs compete for representation in each cortical area Phantom Limb Syndrome ○ Patients can feel their missing limbs moving, even in coordinated gestures ○ Sometimes even report pain ○ Researchers stimulated skin surface in various regions around face, torso, arms while monitoring brain activity in amputees and non-amputee volunteers Displayed the somatosensory cortical areas were activated when skin was stimulated, enabling researchers to map how touch is represented in somat cortex for dif areas of the body In the amputees, stimulating areas of the face and upper arm activated an area in the somat cortex that previously would’ve been activated for the missing hand Face and arm represented in somat in area adjacent to where person’s hand would’ve been represented Stimulating the face/arm produced phantom limb sensations ○ Can be explained by brain plasticity ○ Cortical representations for face and upper arm normally lie on either side of the representation for the hand Face and upper arm areas were larger in amputees New face and arm representations were now contiguous with each other Experts in certain fields have larger brain areas depending on what information they use and need the most ○ Taxi drivers → hippocampi, pianists → somat fingers ○ Plasticity works to help us adapt to our environments Physical exercise can increase number of synapses and promote development of new neurons in the hippocampi ○ Some researchers believe this activity-dependent brain plasticity is relevant to treating spinal cord injuries Cultural Neuroscience: study of how culture and neurobiological processes influence one another ○ Growing evidence that culture impacts neurobiology ○ Ex: people from Western + Eastern cultures process visual info differently Westerners focus more on focal objects, whereas Easterners focus more on background 3.5: Genes, Epigenetics, and the Environment: (on midterm 2) Gene: major unit of hereditary transmission Genes are organized into large threads = chromos = strands of DNA wound around each other in a double helix configuration ○ DNA in chromos produce protein molecs thru mRNA Communicates copy of dna code to cells that produce proteins ○ Chromos come in pairs (humans have 23 each) Similar but not identical Inherit 1 from father and 1 from mother  Selection of each pair given to you is random Males = XY, Females= XX ○ Determined by what you receive from father As a species we share about 99% of the same DNA, but a portion varies across individuals ○ Children share most of this variable dna with their parents Share half their genes with each parent, ¼ with grandparents, etc ○ Probability of sharing genes = degree of reatedness ○ Most genetically related people = monozygotic twins Develop from splitting of fertilized egg, share 100% of their DNA ○ Dizygotic twins develop from 2 separate fertilized eggs, share 50% of their genes Researchers try to determine relative influence of genetics on behavior ○ One method of determining this is to compare a trait shown by monozygotic twins with the same trait among dizygotic twins Enlists twins who were raised in same household, minimizing impact of the environment ○ Finding monozygotic twins with higher presence of a specific trait suggests genetic influence ○ If one twin has schizophrenia odds other one will is 27% in diz, 50% in monoz 50% likelihood can be traced to genetic factors Other 50% must be due to environmental influences ○ Genetic can contribute to development/likelihood/onset of a variety fo traits ○ Must always take the environmental context intoconsideration, as genes express themselves within an environ, not in isolation Epigenetics: the study of environmental influences that determine whether or not genes are express, or the degree to which they are express, without altering the basic DNA sequences that constitute the genes themselves ○ Environment can influence gene expression through epigenetic marks ○ Epigenetic marks = chemical modifications to dna that can turn genes on/off Dna methylation: adding a methyl group to DNA Role of epigenetic writers Switches off the methylated gene Gene is still there but its contents are not expressed Histone modification: adding chemical modifications to proteins called histones that are involved in packaging dna Dna is tightly wrapped around groups of histone prots Can either switches genes on/off ○ Experience can create epigenetic differences between monozygotic twins They are epigenetically indistinguishable early, but then accumulate experience that separates their identicality ○ Epigenetic marks play a role in learning + memory ○ Studies have linked epigenetic changes with responses to stress ○ Epigenetics may play role in transmitting consequences of trauma across generations  Holocaust survivors inherited reduced methylation of FKBP5, associated with regulation of stress response Epigenetics play key role in long lasting effects of early experiences ○ Notable difference sin mothering styles of rats Some mother spend a lot of time likcing and grooming young pups (high LG mothers), others spend little time doing so (low LG mothers) Researchers found pups of high LG moms are much less fearful as adults when placed in stressful situations Same effects obtained when offspring of high LG mothers are raised by low LG mothers, and vice versa ○ Effects were accompanied by physiological changes When in fear inducing situations adult rats raised by high LG moms showed lower levels of severela stress related hormones Increase evidence of hippocampal serotonin → elevated mood ○ Increased serotonin response produced by high LG mothers triggers a decrease in DNA methylation of the glucocorticoid receptor gene → greater expression of gene and corresponding ability to respond calmer to stress ○ Rats raised by low LG moms showed increased DNA methylation of glucocorticoid receptor gene → reduced expression of gene, corresponding inability to respond calmly to stress ○ Children raised in economically disadvantaged niehgborhoods showed greater DNA methylation in genes linked to inflammation and smoking Epigenetic changes may constitute a biological pathway engenders long term health disparities ○ Epigenetics linked to depression, schizo, ptsd Heritability: measure of the variability of behavioral traits among individuals that can be accounted for by genetic factors ○ Calculated as a proportion ranging from 0-1 0 = genes do not contribute, 1 = genes are the only contributing factor Indicate that inviidual differences are caused by varying degrees of genetic and environmental contributions Almost all human behavior is between.3-.6 Intelligence =.5 ○ 4 important drawbacks Abstract concept: tells us nothing about specific genes that contribute to trait Population concept: guidance for understanding differences across individuals in population rather than abilities within an individual Dependent on Environment: meaningful only for environmental conditions in which it was computed → may change drastically under other enviro conditions Not fate: not useful for determine how individuals will respond to particular environmental conditions/treatments Investigating the Brain  Studying damaged brain ○ Much research seeks to link loss of specific perceptual, motor, emotional, cognitive functions with specific areas of brain damage ○ Damaged is dif than atypical More appropriate to use neurotypical, not normal Paul Broca ○ Had patient who lost capacity to produce spoken language Carl Wernicke ○ Patient with an impairment in language comprehension but not speech production Phineas Gage ○ Iron rod went thru his frontal lobe changing his personality completely Before accident he was mild mannered, quiet, conscientious, hard working After he was irritable, irresponsible, indecisive, profane ○ Allowed scientists to better understand frontal lobe and its interactions with the limbic system Right and Left Hemispheres ○ Disorders can threaten ability of brain to function ○ Severe epilepsy → seizures begin in one hemisphere and spread to other via the corpus callosum ○ To alleviate seizures drs can severe corpus callosum = split brain procedure Helps with seizures but produces some unusual behavior ○ Normally any info that initially enters left h is also registered in right h and vice versa Info comes in and travels across corpus callosum ○ Person with split brain, info entering one hemisphere stays there ○ Roger Sperry Asked person with split brain to look at center spot on a screen, then projected a stimulus either on the left or right side of the screen, isolating stim to opposite h ○ Hemispheres specialized for dif kinds of tasks Language processing/speaking left hemisphere activity But if asked to reach behind screen with their left hand and pick up objec they just saw there would be disconnect and they wouldn’t be able to do so Electroencephalography (EEG): device used to record electrical activity in the brain ○ Electrodes placed on outside of head, EEG can amplify electrical signals several thousand times, providing visual rep of electrical activity (measure electrical activity on scalp) ○ Researchers can determine amount of brain activity during dif experiences and states of consciousness Ex: distinct electric activity when awake vs when asleep  ○ Can be used to see brain activity when engaged in psychological functions such as learning, perceiving, remembering ○ Used for: disorders of electrical activity (epilepsy, sleep, migraine) and cognitive research ○ Noninvasive, relatively inexpensive it is widely used (research/medicine) David Hubel & Torsten Wiesel inserted electrodes into occipital lobes of anesthetized cats, observed patterns of action potential in individual ns ○ Amplified action potential with loudspeaker so they could hear signals as clicks, see them on an oscilloscope ○ Flashed lights in front of cats, discovered ns in primary visual cortex are activated whenever a contrast between light + dark occurs ○ Found each n responde vigorously to only when presented with a contrasting edge a particular orientation Studies since then have advanced this response to contrast, shape, color ○ Ns in the visual cortex = feature detectors b/c they selectively respond to certain aspects of a visual image Other studies have identified a variety of features detected by sensory neurons ○ Some visual processing ns in temporal lobe are activated only when detecting faces Specialized for processing faces so damage to this area results in an inability to perceive faces Neuroimaging Techniques ○ Structural brain imaging provides info about basic structure of brain + allows clinicians/researchers to see changes/abnormalities ○ Functional brain imaging: provides info about activity of the brain while people perform various kinds of cognitive/motor tasks Structural Brain Imaging ○ Computerized Axial Tomography (CT scan) One of first neuroimaging techniques Scanner rotates a device around person’s head and takes series of x ray photos from dif angles Computers combine images to provide view from any angle Show dif densities in tissue of brain Higher density looks whiter (like skull)