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PSYCHOLOGY AND SCIENTIFIC THINKING Psychology – the scientific study of the mind, brain and behavior Psychology in Popular cultures Social media, internet TV, movies Self-help books Magazine...

PSYCHOLOGY AND SCIENTIFIC THINKING Psychology – the scientific study of the mind, brain and behavior Psychology in Popular cultures Social media, internet TV, movies Self-help books Magazine Friends/family Observing the world Popular Psychology Knowledge is not always true. All the statements below are false. Most people use only about 10% of brain Not one level of analysis is “best” capacity. Hypnosis enhances the accuracy of our Main Challenges in Psychology memories. 1.) Actions are multiply determined – different The lie-detector (polygraph) test is 90-95% levels of explanation, produced by many accurate at detecting falsehoods. factors The more people present at an emergency, 2.) Psychological Influences are rarely the more likely it is that at least independent – factors are highly one of them will help. associated by one another All effective psychotherapies require clients o Difficult to determine which cause is to get to the root of their problems operating in childhood. 3.) Individual differences among people – Psychology is more than common sense. difference in terms of thinking, emotion, personality, and behavior Common sense – useful for some purposes but o Challenging to find explanations that sometimes it is wrong → use of scientific studies apply to everyone Many psychology findings seem obvious. Scientific Theory – explanation for many findings in the natural world Obvious vs Non-obvious Findings Hypothesis – testable prediction derived from a Obvious Findings scientific theory – conclusions that align with common sense Theory Example: Negative attentional bias or everyday experiences in depression. – unsurprising or self-evident. Hypothesis Example: Depressed individuals – eg: Good partners make good parents will focus more on negative words in a memory test compared to non-depressed Non-obvious Findings individuals. - conclusions that defy common sense or are Confirmation Bias – tendency to seek out counterintuitive evidence that supports our hypotheses and deny - often surprise people or seem illogical evidence that contradicts them without deeper explanation - eg: Burglar alarms are linked to increased “tunnel vision” burglary risk & Winning the Lottery “Are dogs better than cats?” “Are cats better than dogs?”  Hastorf and Cantril (1954) Football Principle #2: Correlation Isn’t Causation Game Study o Dartmouth fans saw Princeton - Correlation-causation fallacy – error in players as committing more assuming that because one thing is penalties and vice versa. associated with another, it must cause the other Psychological Pseudoscience - Variable- anything that can var - Set of claims that seems scientific but isn’t - testable Dangers of Pseudoscience Opportunity Cost (Indirect Harm) – people may forgo opportunities to seek effective treatments Principle #3: Falsifiability Direct harm – cause psychological or physical harm (even death) - Capable of being disproven In ability to think scientifically as citizens - Theory could be proven wrong if there were certain type of evidence against it Warning Signs of Pseudoscience o Risky prediction – good chance of being wrong Overreliance on anecdotes – no cause and effect, no information how representative Principle #4: Replicability the cases are o Anecdote – story about a single - Study findings can be duplicated, ideally by person independent investigators Meaningless “psychobabble” – use of - If it cannot be duplicated, it increases the scientific-sounding words that don’t really odds it was due to chance mean anything Principle #5: Extraordinary claims require o Neuropower extraordinary evidence Talk of “proof” instead or evidence – lacks scientific reasoning which provides - David Hume (18th-century Scottish evidence that supports or contradicts ideas philosopher): the more a claim contradicts ▪ Use “suggests”, “appears”, what we already know, the more persuasive “raises the possibility that” the evidence must be to accept it o “Our new program is proven to reduce social anxiety by at least Principle #6: Parsimony (Occam’s Razor) 50%!” - If two explanations account equally well for Scientific Skepticism - evaluating all claims with a phenomenon, we should generally select an open mind, but insisting on persuasive evidence the more parsimonious one before accepting them - Guideline, not a rule Scientific Thinking Principles PSYCHOLOGY’S ROOTS IN GREEK PHILOSOPHY Principle #1: Ruling Out Rival Hypothesis Psychology = psyche + logos - “are there any alternative explanations for the findings? Have they been excluded?” Psyche – soul, spirit, or mind - Multiple explanations may fit psychological Logos – the study of a subject findings (X → Y or Z → Y) Ancient Greek Philosophers: Socrates, Plato, o Think of ways through experimental and Aristotle debated: design to get at the mind Mind vs. body Historical Study of Psychology/ the Mind o René Descartes (1596-1650) ▪ Human behaviors are 1800s: Roadblocks existed. mechanistic → body (physical o Not possible for the mind to study reflexes) – fast and automatic itself. ▪ Other behaviors are based on o Properties of the mind can’t be reason → mind (soul) – measured. slower but more deliberate, logical thinking o No neuroimaging yet ▪ Dualism – mind and body, although separate, acts Decision making and Franciscus Donders together through the pineal (1868). gland o Dutch physiologist Nativism vs. empiricism (nature vs nurture) o Research Question: How long does it o Nativism – knowledge is innate take a person to make a decision? o Empiricism – knowledge comes from experience DONDERS’ REACTION TIME EXPERIMENT A Modern-Day Mind vs. Body Research Example - Reaction Time (RT): How long it takes to respond to a stimulus. (measured in Lorina Naci, Adrian Owen, and colleagues (2014) milliseconds) Study - 2 conditions Healthy participants and brain-injured o Simple RT – press J when light goes patient. on o Sam- vegetative state for 16 years o Choice RT – press J for left, K for right ▪ Awake but no sign of awareness Watched a suspenseful, eight-minute clip of Hitchcock's Bang! You’re Dead. Moment-to-moment brain activity in relation to the movie content was highly similar. (watch vid) o Choice RT – Simple RT = Decision o FMI Imaging – measures brain Time (typically 100 milliseconds activity difference) o Brain activity increases during o Isolates “decide which button to suspenseful activity in the movie push” o Similar brain activity compared to ▪ How long someone makes a normal people decision o Body is responsive but mind is still Importance o One of the first psychology active experiments to develop psychology Important Points to Consider as science o Mental response cannot be measure The mind is hidden from view. directly but can be inferred from o Access with neuroimaging behavior The mind is difficult to study. A New Science is Born Lasting Scientific Influence of Structuralism In 1879, Wilhelm Wundt developed the first Correctly emphasized the importance of psychology lab in Leipzig, Germany. systematic observation. Scientifically examine consciousness - the o Follows a set of procedure awareness of immediate experience. Wundt’s methods used qualitative and quantitative data. Research Questions included: o Qualitative – description o Quantitative – objective, numerical How different must two colours be to tell them apart? Early work by Ebbinghaus: Memory and How long does it take to react to a sound? Forgetting What thoughts occur when we solve a math problem? – complex thinking - Ebbinghaus (1885) studied lists of nonsense syllables then recalled them WUNDT’S METHODS aloud. (not part of structuralism) o Repeated this until he had no 1. RT experiments. errors. 2. Introspection- method by which trained o 1,000 seconds to learn a list for observers carefully reflect and report on the first time. their mental experiences. o Research Question: How rapidly Visual stimuli or auditory tones. → do we lose learned information? presented stimuli and then report on ▪ After a break, he relearned what you are experiencing when the list. perceiving the stimuli Savings = (Original time to learn list) − (Time STRUCTURALISM: THE ELEMENTS OF THE to relearn list after delay) MIND - Edward Titchener (1867-1927), British student of Wundt. Structuralism aimed to identify the basic elements of the psychological experience. o Wanted to break down consciousness into basic elements or smaller components ▪ Sensations, feelings, images Used introspection. Wanted a comprehensive map of the elements of consciousness. Problems with Structuralism Reports were subjective o Many variations Imageless thoughts WILLIAM JAMES – functionalism o Brought up by Oswald Kulpe o Thinking that occurs without - Influential American psychologist. images or sensory content o Principles of Psychology (1890) – first psychology textbook  - Observations based on the functions of his REEMERGENCE OF THE MIND IN PSYCHOLOGY own mind, not experiments. - Tolman (1948) trained rats to find food in a four-armed maze. ▪ Structuralists asked “what” questions. Functionalists asked “why” questions. o Example: why do we forget things? o Lasting Influence: Perspective has ▪ When a rat was placed in a different arm of been absorbed into modern-day the maze, it went to the specific arm where it psychology. previously found food. BEHAVIOURISM: THE LAWS OF LEARNING Cognitive Maps - Tolman believed the rat created a cognitive map, a representation of the maze in its - Founded by John B. Watson (1913) mind → bringing the idea of the mind back – how the o Criticized the study of consciousness rat developed a map o Psychological science must be objective The Rebirth of the Study of the Mind o Eliminated the study of mind COGNITIVISM: OPENING THE BLACK BOX Behaviorism - focuses on uncovering the general principles of learning underlying animal and human 1950s and 1960s, in response to the behavior behaviorists. First computer available to the general public in 1954. Information-processing approach - Insights from the digital computer. Understand human behaviour in relation to external/environmental factors. o Can be applied to both humans and animals - Drawing similarities in how the mind works and how B.F. Skinner (1938) examined operant computers work conditioning. o Rewards and punishments and how Cognitive psychology- The study of mental they affect behavior processes. Watson focused on classical conditioning. Perception, attention, memory, emotions, o Associations – things are paired language, deciding, thinking, and reasoning. together Thinking affects our behavior in powerful ways. Lasting Influence: Influential in models of human and animal learning. Interpretation in rewards and punishments. Jean Piaget (1896-1980): children think in different ways than adults. Cognitive-Behavioral Therapy  ▪ Cognitive Neuroscience- Examines the Strong role of childhood experiences – how relationship between brain activity and childhood experiences shape us later in life thinking. Came up with talk therapy Which represents a cognitive model of behavior and which represents a behaviorist Lasting Influence: of Psychoanalysis model of behavior? Criticism: Difficult to falsify. o Very difficult to design experiments to look at the conscious mind Importance of childhood development. o Can affect us later in life The idea that some processing is unconscious. o e.g., biases, priming o Priming – exposed to one type of - B image shows theoretical appraoch stimulus influences the response to a subsequent stimulus PSYCHOANALYSIS - Sigmund Freud (1896), Viennese neurologist THE HUMANISTS REVOLT o Psychoanalysis- Focuses on 1950s in opposition to behaviorism and internal psychological processes of psychoanalysis. which we are unaware. Humanism- Emphasizes unique qualities of o Unconscious- contains thoughts, humans. memories, and desires below the Abraham Maslow (1908-1970). surface of conscious awareness. Psychological disorders result from Behaviorism vs. Psychoanalysis hindering of human needs. TYPES OF PSYCHOLOGISTS: Type Focus Psychological Life is Filled with Symbols Clinical Mental disorders Concept of the unconscious based on Psychologist observations. Psychiatrists Medicine and mental “Freudian Slips” disorders o “I decided to take a summer school curse.” Counselling Temporary problems o “I'm mad you're here.” Psychologist ▪ Reveal hidden meaning School Help children and Dream Analysis - what is the hidden Psychologist youth meaning behind dreams  Developmental Study how and why Selection of the research method is crucial Psychologist people change over for what conclusions you can make. X → Y time. Guiding Principles for Applying the Scientific Experimental Use research Method to Psychology Psychologist methods to study: Perception, attention Guiding Principle #1: Generalizability and memory, - External validity language, thinking, - measure of how useful the results of a study social behaviour. are for a broader group of people or Biological Examine the situations Psychologist physiological bases - Need a representative sample of the of behaviour in population. animals and humans. - Population depends on the research Forensic Assess and diagnose question. Psychologist inmates. Random Selection- Procedure that ensures Conducts research. every person in the population has an equal Industrial- Work with companies chance of being chosen to participate. Organizational to: Psychologist Select/evaluate Random Selection Examples employees Research working environment conditions Non-random selection reduces the generalizability of studies Research Q: How does the average person feel EVOLUTIONARY PSYCHOLOGY about Drake? Applies Darwin’s theory of natural selection Should we ask 100 randomly sampled to human and animal behaviour. people in North America or 100,000 people o E.g., anxiety. in Toronto? o Controversial - evolutionary theory Election data: If polling is non-random, challenges certain religious views, election forecasts can be inaccurate. ideas about human uniqueness, and Guiding Principle #2: Reliability is sometimes misunderstood o E.g., Male baldness, adaptive or - Consistency of measurement not? - A reliable questionnaire should yield similar scores over time = test-retest reliability RESEARCH METHODS Interrater Reliability Research methodology is a way to systemically solve or answer a research problem. Extent to which different people agree on the characteristics they are measuring.  Example: Two psychologists giving Conduct in real time or video recordings. separate diagnoses (low or high IR?). Also, social media. Example: job interview panel all like a Wearable technologies. candidate (low or high IR?). Robert Provine’s (1996, 2000) Investigation of Guiding Principle #3: Validity Laughter Example - Construct validity Listened to 1200 instances of laughter in - extent to which a measure assesses what it social situations. claims to measure Recorded: Example: Giving a math test to measure o Gender (who tended to laugh numeracy (low or high validity?). more?) Example: Questionnaire to measure o Preceding remarks (what % of depression, but it’s really measuring anxiety laughter was preceded by a funny (low or high validity?). statement?) o Reaction of speaker vs. listener Reliability vs. Validity (who tended to laugh more?) - valid test must also be reliable, but a Results: reliable test can be completely invalid - polygraph Women tended to laugh more than men while men were more likely to be the ones “Distance Index-Middle Width Intelligence Test” eliciting the laughter Example less than 20% of the laughter followed a funny or intentionally humorous statement Subtracts the width of our index finger from our speaker laughed more than the listener in middle finger. social interactions o high test-retest reliability. Wansink and van Ittersum (2013)’s Buffet Study Example o high interrater reliability. Large plate vs. small plate diners o BUT, is this a valid measure of o Chose, consumed, and wasted more intelligence? food TYPES OF RESEARCH DESIGNS Pros and Cons of Naturalistic Observation Descriptive Studies and Correlational Research Studies Psychologists can’t always exert experimental High in external validity. control over variables. o Good starting point. o Example 1: Nutritious vs. non-nutritious o Can be used to study animal maternal diets on the health of babies. behaviour. o Example 2: How often do people laugh Low internal validity in the real world? o Cannot draw cause-and-effect Only describe patterns of behaviour and inferences discover links/associations between variables. 2.) CASE STUDIES - Examine one person or a 1.) NATURALISTIC OBSERVATION - Watching small number of people behavior in real-world settings without trying to Used to study rare brain damage and/or manipulate the situation. unusual conditions.  Can inspire new hypotheses about the brain Potential for dishonesty. and behavior. 4.) CORRELATIONAL DESIGNS - Strength of Henry Molaison (H.M.) association between two variables Experimental operation to remove portions Correlations can be negative, zero, or of the hippocampus. positive. Observed by Dr. Brenda Milner from McGill. o What direction do the variables Inability to form new memories. move in relation to one another for each type? Face Recognition Correlation coefficients range from −1.0 to +1.0. Prosopagnosia – Extreme impairment of the o Higher absolute value means ability to recognize faces. stronger relationship Fusiform face area (FFA) responds specifically to faces. Pros and Cons of Case Studies High level of detail of rare psychological phenomenon. Question: What about external and internal validity? 3.) SELF-REPORT MEASURES AND SURVEYS Self-report measures (Questionnaires) - assess participant characteristics. o Demographics, personality traits, mental illnesses. Surveys- Measure opinions and attitudes. o Market research, political polls. Survey Challenges: People’s responses can vary depending on how the question is presented Correlation ≠ Causation Open-ended vs. multiple-choice format Agree/Disagree format (one statement) vs. multiple-choice format 5.) Experimental Designs Permit cause and effect inferences o Internal Validity Random assignment of participants to conditions. o Randomly sort participants into one Pros and Cons of Self-Report Measures of two groups Manipulation of an independent variable. Easy to administer. Get direct information about emotions, personality, opinions.  Example 1 Between-subjects Design Can we say that the anxiety drug works in example 1? Example 2 Within-subject Design - participants are their own control group Participants must be blind to what group they are in. Example 3 Independent vs. Dependent Variable - IV: Variable that is manipulated. - DV: Variable the experimenter measures to see if the manipulation has an effect. Simply believing nicotine was present, reduced cravings! Confounds EXPERIMENTER EXPECTANCY EFFECT ▪ Experiments have high internal validity if the IV is the only difference between groups. Confounding variables- Any variable (not the IV) that differs between the experimental and control groups. Experimenter expectancy effect- Researchers’ hypotheses lead them to unintentionally bias the outcome. Double blind designs (experimenter and participants unaware of treatment) prevent this. Demand Characteristics Placebo Effect ▪ Cues that participants pick up allowing them ▪ Improvement because you expect to guess the researcher’s hypothesis. improvement.  o “The effects of horror movies on mood.” o “An investigation of caffeine and memory.” ▪ vs. “Study on University Students’ Film Preferences” Reactivity - Refers to the tendency of participants to change their behavior when they know that they are being observed. - Their behavior might become more positive or negative, depending on the situation. Social Desirability Bias/Positive Impression Management 2. Variance – how loosely or closely scores are related - Our tendency to respond in ways that we feel are more appropriate or socially Range- difference between the highest and acceptable to others. lowest scores - Response sets- Tendency of participants to distort their self-report responses in a Standard Deviation- how far each data positive way. point is from the mean - Try to impress researcher. Calculating Range Example: PSYCHOLOGY AND STATISTICS IQ scores Sample 1: 80, 85, 85, 90, 95 Descriptive statistics - Organize data into meaningful patterns and summaries. Mean = 87; Range: 95 - 80 = 15 1. Central tendency - Where the group data IQ scores Sample 2: 25, 65, 70, 125, 150 tends to cluster, three main measures: Mean = 87; Range: 150 - 25 = 125 mean, median and mode Range vs. Standard Deviation Same range, but different standard Mean is affected by outliers, but the median deviations. and mode are not Standard deviation is smaller for a vs. b. Normal Distribution ETHICAL ISSUES IN RESEARCH DESIGN The Tuskegee Syphilis Study (1932 to 1972)  Participants, 399 African American men, Peripheral Nervous System were diagnosed with syphilis, but not informed. divided into two branches Somatic nervous system - controlling and ▪ Not given treatments, even though coordinating voluntary movement. treatments were available. o Anything we have control over Autonomic nervous system - controls the Stanley Milgram’s Obedience Experiments involuntary actions of our internal organs (1960s). and glands; has two divisions. o Parasympathetic division – rest Measured the willingness of study and digest participants to obey an authority figure. o Sympathetic division – fight or Administered “shocks” to a “learner”. flight Ethical Guidelines for Research Research Ethics Boards (REBs) that oversee research on humans and animals. Informed consent: Participants must know what is involved in the study prior to participation. Purpose Duration Any potential risks or adverse effects Right to withdraw Debriefing At the end of the study, participants should Brain Mapping Methods be fully debriefed about the true nature of the research. Phrenology was one of the earliest methods Should be informed of any deception that (1800s) was used. First way to map the brain THE BRAIN-BEHAVIOUR NETWORK Feels bumps on people’s heads and equate them with behavioral characteristics Biological Psychology - studies the relationship between the nervous system and behavior Skull → Brain→ Psychological Traits The Brain-Behaviour Network Is falsifiable → mappings were not correct Major contribution: spatial organization Communicates via neurons Vast communication Brain Damage and Neuropsychology network. Link areas of damage to cognitive function. ▪ Central nervous system o Humans vs. animals. (CNS) → brain and spinal cord ▪ vs. Peripheral nervous system (PNS) → all nerves outside the brain and spinal cord  ▪ Neuropsychological tests are ▪ Damage to temporal lobe administered. ▪ Long, complete sentences with no ▪ Measure: reasoning, attention, meaning, adding unnecessary words and memory, verbal and spatial ability. creating made-up words. ▪ E.g., Montreal Cognitive ▪ "You know that smoodle pinkered and Assessment (MOCA). that I want to get him round and take care of him like you want before.” ▪ Test to see whether or not people are prone for ▪ “It even stepped my horn. They make Alzheimer’s disease my favourite nine to severed and now I’m a been habed by the uh stam of ▪ See if people are adverse for fortment of my annulment which is now dementia forever.” Localization of Function: Specific functions are ▪ Spared production, impaired served by specific areas of the brain. comprehension. Specific cognitive functions are for certain o Can’t understand speech – can areas – makle assumptions in different speak fully cognitive processes – see where damage is Double Dissociation Example 1: Language (Broca’s Aphasia) If damage to one area causes function A to ▪ Production is impaired by frontal lobe be absent while function B is present, and damage. damage to another area causes function B o Tan; "Walk dog”; "book book two to be absent while function A is present. table" Specific brain areas are involved in specific functions- tie one area to one function o Alright…Uh…stroke and un…I …huh tawanna guy…H…h…hot tub and…And the…Two days when uh…Hos…uh…Huh hospital and uh…amet…am…ambulance. ▪ Able to understand speech. Electrical Stimulation: Early Work o Not able to produce full Wilder Penfield (1891 –1976), neurosurgeon sentences of speech ▪ Stimulate brain with electrical probes→ Assess function. ▪ E.g., Motor cortex, temporal lobes ▪ Brain cells use electrical activity to send information. ▪ Did a lot of surgery with epilepsy patients – cut into skulls Example 2: Language (Wernicke’s Aphasia) ▪ Patients are awake during surgery  ▪ Did experiments – stimulated parts ▪ Magnetic fields to indirectly visualize brain of the brain and looked at what structure. happened to the patients o All of the water molecules and ▪ Useful because it gave evidence that tissues are going to line up neurons use electricity to send according to magnetic field messages o Apply radio frequency current ▪ Useful to localization content o Measure different amounts of energy Recording Electrical Activity from the Brain from the disturbance Electroencephalograph (EEG) ▪ Measures the release of energy from water molecules in biological tissues in relation to Hans Berger (1929) the magnetic field and application of a Measures electrical activity via electrodes radiofrequency current. on the skull. Detects electrical change in the range of milliseconds (ms). Better at when vs. where information. o Really good at timing – really fast (ms scale) Functional Techniques – injected with tracer Positron emission tomography (PET) ▪ Measures consumption of a radioactive glucose-like molecules to give a picture of neural activity. ERP (event-related potential) are derived from averaging EEG signals. o Based on average of EEG brain waves o Changes in activity in relation to change to cognitive events o Demonstrate fast timing information (millisecond scale) P3 ERP (event-related potential) component plays a role in attention and stimulus Functional MRI (fMRI) novelty. ▪ Uses magnetic fields to visualize brain Neuroimaging Techniques activity using changes in blood oxygen level. Structural Techniques o blood-oxygen-level-dependent Computed tomography (CT) (BOLD) signal ▪ X-rays to construct three-dimensional o How the brain is using oxygen – images. parts usin more oxygen will be more Magnetic resonance imaging (MRI) active (shown in fMRI)  Magnetic fields are being applied to influence neural activity Can either enhance activity or it could interrupt/inhibit activity Visual memory = Green Auditory memory = Red THE BRAIN’S COMMUNICATORS Both = Yellow PET and fMRI measures activity on the scale of seconds → better spatial information Magnetoencephalography (MEG) Detects brain Early concept of a nerve net. activity by Camillo Golgi developed a new staining measuring technique (1870s). tiny magnetic o Solution of silver nitrate, < 1% of fields cells become stained. generated by ▪ Neurons are their own the brain. structures Spatial distributions of magnetic fields that Neuron doctrine (Santiago Ramón y can be superimposed onto an MRI scan. Cajal). Temporal (ms scale) and spatial o Individual nerve cells transmit information. signals and are not continuously linked with other cells. Deep Brain Stimulation (DBS) What are Neurons? Modify brain function Neuron: nerve cell specialized for communication. through implanted Conduct action potential electrodes. Electrified membrane gives it special o Implant pulse properties. generator into 86 billion neurons, with 160 trillion synaptic chest connections between them Potential treatment for disorders (e.g., Parkinson’s Disease, obsessive-compulsive disorder, or depression). Invasive Transcranial magnetic stimulation (TMS) Applies strong and quickly changing magnetic fields to the surface of the skull that can either enhance or interrupt brain function. Parts of the Neuron Regulate blood flow. o Found in blood-brain barrier. Dendrites Increase accuracy of neural transmission ▪ Branchlike extensions that receive information. ▪ Increases surface area. Cell body (soma) ▪ Contains mechanisms to keep the cell alive. ▪ Where information assembles. Oligodendrocytes ▪ Contains nucleus ▪ Promote new connections and healing. Axons and Axon Terminals ▪ Produce the myelin sheath around axons→ Action potential is generated Increases speed → of action potential Transmits signals to other neurons. o Myelin sheath – white fatty Synaptic vesicles are spherical sacs substance to wrap axon containing neurotransmitters. o Allows specific information in the brain across synapse Synaptic Transmission Neurons communicate via a combination of electrical and chemical signals o Electrical – going down the axons o Chemical signals – synapse (neurons) Action Potential electric impulse that travels down the axon triggering the release of neurotransmitters (+40 mV). Electrochemical Gradient of the Neuron ▪ Neuronal membrane has an electric potential difference. ▪ A neuron is at rest when it is not sending an electrical signal. Synapse = all components in figure. ▪ During this time, the inside of the neuron is negative relative to the outside → resting Synaptic cleft = gap between two potential connecting neurons through which messages are transmitted chemically o Resting Potential: -70 mV Glial Cells – caretakers of brain Initiating an Action Potential Astrocytes Neurotransmitters open ion channels.  Rapid sequence of changes in the voltage Psychoactive Drugs – impacts brain, moods across a membrane occurs. When a high enough level is reached an Agonists increase activity of the action potential is triggered. neurotransmitter system o Threshold of Excitation: -55mV → o Opioids (like codeine and morphine) slightly less negative (trigger value) mimic endorphins o Increase activity Reuptake inhibitors o Anti-depressants – keep serotonin longer o Keep neurotransmitter in synapse Antagonists decrease activity of the neurotransmitter system o Dopamine blockers for schizophrenia o Decrease activity of neurotransmitter MAJOR PARTS OF THE BRAIN Depolarization – it becomes less negative and be in trigger threshold Repolarization – goes slowly back to resting potential stage Hyperpolarization – super negative, more than resting value Action Potential Is an all-or-none response. o Fire or does not fire o Needs threshold of excitement Cerebral Cortex Is followed by an absolute refractory period. Frontal: Executive functions, motor o Limits maximal firing rate planning, language, and decision making. Parietal: Processes touch information; Neurotransmission integrates senses. Receptor sites are specialized to receive Temporal: Processes auditory information, only certain types of neurotransmitters. language, and long-term memory. o Lack and key Occipital: Processes visual information. Reuptake: when neurotransmitters go back Two cerebral hemispheres connected by the into the axon terminal. corpus callosum (white huge mater) o Recycled back to presynapse Key Neurotransmitters  Outer layer of cortex contains grey matter. Railroad worker in 1848. Inner part is white matter. Iron rod exploded and thrust into his head. o Diffusion tensor imaging (DTI) → Destroyed most of his left prefrontal structural cortex. Remarkable behavioral changes following Split Brain Surgery injury (“no longer Gage”). Procedure that involves severing the corpus o More impulsive, less callosum to reduce the spread of epileptic Parietal Lobe seizures. Contains the somatosensory cortex → sensation, similar to motor cortex Relays visual and touch information to the motor cortex. Spatial perception. Unilateral neglect. Fail to attend to opposite side of damage. → ignoring one side Frontal Lobes Executive functioning o Mental flexibility o Command center Body is mapped onto motor cortex. Broca’s area and speech production. Prefrontal cortex responsible for: Thinking, planning, language Mood, personality, self-awareness, self- control Temporal Lobe A role in hearing, understanding language, and storing long-term memories. Auditory cortex and Wernicke’s area (both top of lobe), responsible for speech comprehension Bottom part contains the fusiform face area (FFA) → people not able to see faces Occipital Lobe Located at the back of the brain. Phineas Gage Specialized for vision. Limbic System Emotion and Memory Amygdala - emotion Hippocampus - memory Sensation relay and basic biological needs. Thalamus – sensory information Hypothalamus – biological needs Brain Stem - Serves as a relay station between the cortex and rest of the nervous system Consists of: ▪ Cerebellum: balance and motor skills o “mini brain” ▪ Pons: dreaming, sleep, arousal ▪ Medulla: vital functions o Heart rate, breathing