General Psychology Unit 1 Review (OCR) PDF

General Psychology Unit 1 review (exam 1 material: chapters 1, 2 and 3) What is psychology? Psych – Soul Ology – Scientific study of Psychology – Scientific study of the mind and behavior. Psychologists study everything about the human experience from the...

General Psychology Unit 1 review (exam 1 material: chapters 1, 2 and 3) What is psychology? Psych – Soul Ology – Scientific study of Psychology – Scientific study of the mind and behavior. Psychologists study everything about the human experience from the basic workings of the human brain to consciousness, memory, language, reasoning, personality and mental health. history OF PSYCHOLOGY Psychological perspectives Structuralism – understanding the conscious experience through introspection. - Wilhelm Wundt Functionalism – focused on how mental activities helped an organism adapt to its environment. - William James Psychoanalytic Theory – focuses on the role of the unconscious in affecting conscious behavior. - Sigmund Freud Gestalt Psychology – Focuses on humans as a whole rather than individual parts. - Wertheimer, Koffka, Kohler Behaviorism – focuses on observing and controlling behavior. - Pavlov, Watson, Skinner Humanism - emphasizes the potential for good that is innate to all humans. - Abraham Maslow and Carl Rogers  At some point we started to talk about the mind philosophically (in addition to the spiritual stuff that has always been going on)  Aristotle & mentalism 🡪”nonmaterial” mind 🡪what is consciousness? 🡪Mind vs Psyche The School of Athens , 1509-1511 Raphael Fresco  Dualism “Cogito ergo sum [I think therefore I am].” René Descarte (1596-1650) The mind and body are distinct and separable. And then we started to notice that changes to the brain led to changes in the mind. Phineas Gage (1823-1860) This happened in 1848.  Functionalism William James WILLIAM JAMES (functionalism) William James, shown here in a self-portrait, was the first American psychologist. James drew from the functionality of cognitive processes, establishing functionalism. Functionalism - emphasized how mental activities contributed to basic environmental survival. Mary Whiton Calkins Studied dreams – Woke people up periodically to take notes however trivial. – ”[A dream] merely reproduces in general the persons and places of recent sense perception and that is it rarely associated with that which is of paramount significance in one's waking experience”. Did a dissertation on memory. – Wasn’t given a doctoral degree though. – Paired associates test (recency, vividness, frequency) Margaret Floy Washburn First woman to earn a doctorate in Psychology Researched on animal behavior, and published an authoritative text on the subject. wILHELM WUNDT (structuralism) Wilhelm Wundt is credited as one of the founders of psychology. He created the first laboratory for psychological research. Wundt emphasized structuralism. He focused on understanding the structure and characteristics of the mind through introspection. Introspection - Process by which someone examines their own conscious experience in an attempt to break it into its component parts  SIGMUND FREUD (a) Sigmund Freud was a highly influential figure in the history of psychology. (b) One of his many books, A General Introduction to Psychoanalysis, shared his ideas about psychoanalytical therapy; it was published in 1922. SIGMUND FREUD (psychoanalytic theory) Founded Psychoanalytic theory, a perspective which dominated clinical psychology for many decades. Studied “hysteria” and neurosis. Theorized that many of his patients’ problems arose from the unconscious mind. Believed that one way the unconscious mind could be accessed was through dream analysis. Psychoanalytic theory focuses on the role of a person’s unconscious and early childhood experiences. Freud’s Couch (credit: BBC)  Gestalt psychology Kohler, Koffka and Wertheimer were German psychologists who immigrated to the U.S. to escape Nazi Germany. Gestalt – “Whole” Based on the idea that although a sensory experience can be broken down into individual parts, how those parts relate to each other as a whole is often what the individual responds to in perception. Ideas of Gestalt continue to influence research on sensation Kohler, Koffka, Wertheimer (credit: and perception. Elearning Industry) IVAN PAVLOV (CLASSICAL CONDITIONING) Discovered the concept of classical conditioning. Studied conditioned reflexes in which an animal produced a reflex (unconscious) response to a stimulus (salivating in the presence of food) and, over time, was conditioned to produce the response to a different stimulus (salivating to the sound of a bell) that the experimenter associated with the original stimulus (Food and bell became associated). (Credit: Emaze)  John b. watson (BEHAVIORISM) John B. Watson is known as the father of behaviorism within psychology. Believed that objective analysis of the mind was impossible. Instead he focused on observable behavior and ways to bring that behavior under control. Today, behaviorism is used in behavioral and cognitive-behavioral therapy. B. F. Skinner Concentrated on how behavior was affected by its consequences. Studied the principles of modifying behavior through reinforcement and punishment which he saw as major factors in driving behavior (operant conditioning). ABRAHAM MASLOW (humanism) Proposed a hierarchy of human needs in motivating behavior. Maslow asserted that so long as basic needs necessary for survival were met (e.g., food, water, shelter), higher-level needs (e.g., social needs) would begin to motivate behavior.  CARL ROGERS (humanism) Carl Rogers developed a client-centered therapy method that has been influential in clinical settings. Client-centered therapy involves the patient taking a lead role in the therapy session. Rogers believed therapists need: - unconditional positive regard - genuineness - empathy The cognitive Revolution By the 1950’s, new disciplinary perspectives in linguistics, neuroscience, and computer science were emerging. The mind became the new focus of scientific inquiry. Noam Chomsky Noam Chomsky was very influential in beginning the cognitive revolution. He believed psychology needed to incorporate mental functioning into its focus in order to fully understand human behavior. Mamie Phipps Clark and Kenneth Clark Feminist Psychology Contemporary psychology Branches of psychology Biopsychology and Evolutionary Psychology Sensation and Perception Cognitive Psychology Developmental Psychology Personality Psychology Social Psychology Health Psychology Industrial-Organizational Psychology Sports and Exercise Psychology Clinical Psychology Forensic Psychology biopsychology Biological psychologists study how the structure and function of the nervous system generate behavior. Research can include: - Sensory and motor systems - Sleep - Drug use and abuse - Ingestive behavior - Reproductive behavior - Neurodevelopment - Plasticity of the nervous system - Biological correlates of psychological disorders Sensation and perception This area of study focuses on both physiological aspects of sensory systems and the psychological experience of sensory information. Sensation – Sensory information (sights, sounds, touch, smell). Perception – Experience of the world which is influenced by where we focus our attention, our previous experiences, and our cultural backgrounds. When you look at this image, you may see a duck or a rabbit. The sensory information remains the same, but your perception can vary dramatically. developmental PSYCHOLOGY Developmental psychology studies the physical and mental attributes of aging and maturation. This can include various skills that are acquired throughout growth. - Moral Reasoning - Cognitive Skills - Social Skills Jean Piaget is famous for his theories regarding changes in cognitive ability that occur as we move from infancy to adulthood.  Personality psychology Focuses on behaviors and thought patterns that are unique to each individual. Studies in this field include conscious and unconscious thinking and identifying personality traits. FIVE FACTOR MODEL Figure 1.14 Each of the dimensions of the Five Factor model is shown in this figure. The provided description would describe someone who scored highly on that given dimension. Someone with a lower score on a given dimension could be described in opposite terms. Social psychology How individuals interact and relate with others and how such interactions can affect behavior. - Prejudice - Attraction - Interpersonal conflicts - Obedience Health psychology Branch that focuses on how individual health is directly related or affected by biological, psychological, and sociocultural influences. The biopsychosocial model suggests that health/illness is determined by an interaction of these three factors. Clinical psychology Focuses on diagnosis and treatment of psychological disorders and problematic patterns of behavior. Study involves clinical therapy and counseling. Cognitive-behavioral therapists take cognitive processes and behaviors into account when providing psychotherapy. This is one of several strategies that may be used by practicing clinical psychologists. Why is research important? At one time in history, people believed the earth was flat and that mental illnesses were caused by possession. People can be very wrong in their ideas about the world when they do not rely on evidence to support their claims. Research is a mandatory process in validating claims. Scientific research is empirical; it is grounded in objective, tangible evidence that can be observed time and time again, regardless of who is observing. Without research, we would only have intuition and groundless assumptions. Through research we are able to prove certain ideas through study and testing. Figure 2.2 Some of our ancestors, across Psychology is a science, therefore, research is the world and over the centuries, required to not only further investigate something believed that trephination—the practice of making a hole in the skull, as but provide verification and support of the findings. shown here—allowed evil spirits to leave the body, thus, curing mental illness and other disorders. (credit: “taiproject”/Flickr) Use of research information Advertising campaigns often claim to be based on “scientific evidence” when in reality it is based off of belief. Thinking critically about claims: - What is the expertise of the person making the claim? - What might they gain if the claim is valid? - Does the claim seem justified given the evidence? - What do other researchers think of the claim? The process of scientific research: Inductive vs Deductive reasoning Deductive reasoning - results are predicted based on a general premise. - All living things require energy to survive (premise), ducks are living things, therefore ducks require energy to survive (conclusion). Inductive reasoning - conclusions are drawn from observations. - You see many fruit growing on trees and therefore assume all fruit grows on trees. 1. Scientists form ideas (theories/hypotheses) through deductive reasoning. 2. Hypotheses are then tested through empirical observations and scientists form conclusions through inductive reasoning. Psychological research relies 3. These conclusions lead to new on both inductive and theories and hypotheses (or more deductive reasoning. broad generalizations). The scientific method Scientists use inductive reasoning to form theories which then generate hypotheses. Theory – well-developed set of ideas that propose an explanation for observed phenomena. Hypothesis – tentative and testable statement (prediction) about the relationship between two or more variables. - Predicts how the world will behave if the theory is correct. - Usually an “if-then” statement. - Is falsifiable (capable of being shown to be incorrect). The scientific method of research includes proposing hypotheses, conducting research, and creating or modifying theories based on results. 2.2 Approaches to research Clinical or case studies Naturalistic Observation Surveys Archival Research Longitudinal and Cross-Sectional Research Clinical or case studies Clinical or case studies focus on one individual. The studied individual is typically in an extreme or unique psychological circumstance that differentiates them from the general public. - Allows for a lot of insight into a case. - Difficult to generalize results to the larger population. Example: Genie Genie was studied by psychologists after she was found at age 13, having suffered severe abuse and social isolation. Psychologists were interested in the effect social isolation had on her development. (Credit: Captive Humans) Figure 2.7 Observation of behavior in its natural setting. Naturalistic behavior is generally hidden under scrutiny or observation. - Seeing a police car behind you would probably affect your driving behavior. To study the most accurate and genuine behaviors, naturalistic observation has proven most effective. Through naturalistic observations, any feeling of performance or anxiety of the studied individuals is eliminated. Observer bias - when observations may be skewed to align with observer expectations. - Establishment of clear criteria to observe should help eliminate observer bias. Seeing a police car behind you would probably affect your driving behavior. (credit: Michael Gil)  Figure 2.8 (a) Jane Goodall made a career of conducting naturalistic observations of (b) chimpanzee behavior. (credit “Jane Goodall”: modification of work by Erik Hersman; “chimpanzee”: modification of work by “Afrika Force”/Flickr.com) surveys A list of questions that can be delivered in many ways: - Paper-and-pencil - Electronically - Verbally Surveys can be used to gather a large amount of data from a sample (subset of individuals) from a larger population. Surveys can be administered in a number of ways, including electronically administered research, like the survey shown here. (credit: Robert Nyman) Archival research Uses past records or data sets to answer various research questions, or to search for interesting patterns or relationships. A researcher doing archival research examines records, whether archived as a (a) hardcopy or (b) electronically. (credit “paper files”: modification of work by “Newtown graffiti”/Flickr; “computer”: modification of work by INPIVIC Family/Flickr) Longitudinal and Cross-Sectional Research Cross-Sectional Research – Compares multiple segments of a population at a single time (such as different age groups). Longitudinal - Studies in which the same group of individuals is surveyed or measured repeatedly over an extended period of time. Researchers often expect some participants to drop out, particularly in this type of study and therefore often initially recruit a lot of participants. Attrition - reduction in number of research participants as some drop out of the study over time. Longitudinal research like the CPS-3 help us to better understand how smoking is associated with cancer and other diseases. (credit: CDC/Debora Cartagena) Correlational research Correlation – Relationship between two or more variables; when two variables are correlated, one variable changes as the other does. Correlation Coefficient - number from -1 to +1, indicating the strength and direction of the relationship between variables, and usually represents by r. Positive Correlation – Two variables change in the same direction, both becoming either larger or smaller. Negative Correlation - two variables change in different directions, with one becoming larger as the other becomes smaller; a negative correlation is not the same thing as no correlation. Scatterplots are a graphical view of the strength and direction of correlations. The stronger the correlation, the closer the data points are to a straight line. Correlation does not indicate causation Cause-and-effect relationship - changes in one variable cause the changes in the other variable; can be determined only through an experimental research design. Confounding variable - unanticipated outside factor that affects both variables of interest, often giving the false impression that changes in one variable causes changes in the other variable.. Example: As ice-cream sales increase, so does the overall rate in crime. A relationship exists between ice-cream and crime but is it correlation or does one cause the other? In this example, temperature is a confounding variable. As the temperature increases, ice-cream sales increase and people are more likely to be outside increasing crime rates. Designing an experiment EXPERIMENTAL AND CONTROL GROUPS Experimental group - The participants that experience the manipulated variable (group designed to answer the research question). Control group - Participants that do not experience the manipulated variable. - Serve as a basis for comparison and controls for chance factors that might influence the results of the study Experimental manipulation is the only difference between the experimental and control groups, so any differences between the two are due to experimental manipulation rather than chance. DEFINING VARIABLES AND HOW THEY WILL BE MEASURED Operational definition - description of what actions and operations will be used to measure the dependent variables and manipulate the independent variables. Designing an experiment AVOIDING BIAS AND THE PLACEBO EFFECT Experimenter bias - researcher expectations skew the results of the study. Participant bias – participant expectations skew the results of the study. Single-blind study - experiment in which the researcher knows which participants are in the experimental group and which are in the control group but participants do not. (Controls for participant expectations). Double-blind Study - experiment in which both the researchers and the participants are blind to group assignments. (Controls for both participant and experimenter expectations). Placebo effect - people’s expectations or beliefs influencing or determining their experience in a given situation. - When people are given a pill to improve their mood their mood may increase just because they believe it will. - To know if a medication is really having an effect or whether it us a placebo effect, the experimental group receive the medication and the control group receive a placebo treatment (a sugar pill). This is a double-blind study. - Any differences between the groups will be due to the medication. Figure 2.16 Providing the control group with a placebo treatment protects against bias caused by expectancy. (credit: Elaine and Arthur Shapiro) variables Independent Variable – Variable that is influenced/controlled by the experimenter. Ideally this should be the only important difference between the experimental and control group. Dependent Variable – Variable that the researcher measures to see how much effect the independent variable had. In an experiment, manipulations of the independent variable are expected to result in changes in the dependent variable. (credit “automatic weapon”: modification of work by Daniel Oines; credit “toy gun”: modification of work by Emran Kassim) Selecting participants Participants – Subjects of psychological research. Populations are too large for a researcher to include everyone so samples are used. Sample - subset of individuals selected from the larger population. Population – overall group of individuals that the researcher is interested in (e.g. College students). Random Sample - subset of a larger population in which every member of the population has an equal chance of being selected. - This form of sampling is preferred because it is more likely that the selected participants will be Researchers may work with (a) a large representative of the larger population or (b) a sample group that is a subset of the larger population. (credit “crowd”: population (sex, ethnicity, social modification of work by James Cridland; credit economic status etc). “students”: modification of work by Laurie Sullivan)  assigning participants TO GROUPS: experimental OR CONTROL Random Assignment – Method of experimental group assignment in which all participants have an equal chance of being assigned to either group. - Can be achieved using statistical software or by simply flipping a coin. - Prevents systematic differences between groups such as gender or age. Without random assignment, an experiment cannot find a true cause-and-effect relationship. Any relationship could be due to preexisting differences between the groups. Random assignment helps to avoid preexisting systematic differences so that any significant differences between groups can be said to be the result of the manipulation. Reliability and validity Reliability - consistency and reproducibility of a given result. - Would the same test give the same results every time? - Do the instruments/tools used to collect data do so in consistent, reproducible ways? When a study involves observations by multiple people, it is important that they all make observations and record them in the same way. Inter-rater reliability - measure of agreement among observers on how they record and classify a particular event. A reliable, consistent measurement does not always meant that it is measuring something correctly. Validity - accuracy of a given result in measuring what it is designed to measure. - Does a test measure what it is meant to measure? A valid measure is always reliable but a reliable measure is not always valid. Ethics: research involving human participants Research involving human participants must adhere to strict guidelines. Institutional Review Board (IRB) – Committee of administrators, scientists, and community members that reviews proposals for research involving human participants. - Exist at any research institution that receives federal support for research involving human participants. - Generally, IRB must approve research proposal before it can proceed. Informed consent - process of informing a research participant about what to expect during an experiment and then obtaining the person’s consent to participate. Includes: - Potential risks involved - Implications of the research - Notification that participation is voluntary - Notification that any data collected will be kept confidential An institution’s IRB meets regularly to review experimental proposals that involve human participants. (credit: modification of work by Lowndes Area Knowledge Exchange (LAKE)/Flickr) Deception Sometimes deception is necessary to prevent the participant’s knowledge of the research question affecting the results as long as it is not considered harmful. Deception – Purposely misleading experiment participants in order to maintain the integrity of the experiment. Debriefing - when an experiment involved deception, participants are told complete and truthful information about the experiment at its conclusion. The Tuskegee Syphilis study Ethical guidelines have not always existed. In 1932, participants were recruited in an experiment studying syphilis in black men. Participants that tested positive were not informed that they had the disease. Although no cure existed at the beginning of the study, a cure was found in 1947 (penicillin), but it was not administered to participants. Many participants unknowingly spread the A participant in the Tuskegee Syphilis disease and many died. Study receives an injection. Ethics: Research involving animal subjects - 90% of psychological research involving animal subjects uses rodents or birds. - Animals make good substitutes because many of their basic processes are sufficiently similar to those in humans. - Animals are used when the research would be unethical in human participants. - Researchers must still aim to minimize pain or distress. Institutional Animal Care and Use Committee (IACUC) - committee of administrators, scientists, veterinarians, and community members that reviews proposals for research involving non-human animals. Rats, like the one shown here, often serve as the subjects of animal research. Biopsychology Biopsychology explores the biological mechanisms that underlie behavior. Among many things, it studies: - Genetics - focusing on how inherited genes can affect not just the physiological, but psychological traits of a person. - The structure and function of the nervous system. - How the nervous system interacts with the endocrine system. Different brain imaging techniques provide scientists with insight into different aspects of how the human brain functions. Left to right, PET scan (positron emission tomography), CT scan (computed tomography), and fMRI (functional magnetic resonance imaging) are three types of scans. (credit “left”: modification of work by Health and Human Services Department, National Institutes of Health; credit “center”: modification of work by “Aceofhearts1968”/Wikimedia Commons; credit “right”: modification of work by Kim J, Matthews NL, Park S.) A gene is a segment of DNA which can associate with a protein A genotype is all the genes that you have. A phenotype is all the genes that you actually express.  A mutation is when a nucleotide changes. This can make a gene associate to a different protein. The brain creates behavior. The brain is made of proteins. Proteins are created by DNA. DNA evolves. Therefore, behavior evolves. Basic Cell Anatomy  Main types of cells in the brain. Neurons Glia Basic Structure of a Neuron Core region called the cell body, or soma Branching extensions, or dendrites, collect information from other cells. Main root is the single axon, which carries messages to other neurons. – A neuron has only one axon, but most have many dendrites. The Basis Neurons of Information Processing: Neurons – Most behaviors are produced by groups of hundreds or thousands of neurons. – Functional groups of neurons, or neural networks, connect wide areas of the brain and spinal cord. – An ongoing effort aims to map the structural connectivity—the physical wiring, or connectome—of the entire human brain. – Each neuron’s appearance is distinctive, but neurons are also the essence of plasticity. Major Parts of a Neuron Subdivisions of Neurons Three basic subdivisions of neurons – Dendrites Gather information from other neurons. – Cell body, or soma Is the core region, which contains the nucleus. Integrates the information. – Axon Carries information to be passed on to other cells. Information Flow Through a Neuron HUMAN GENETICS Studying human genetics can help researchers understand the biological basis underlying the different behaviors, thoughts and reactions of humans. - Why do two people infected by the same disease have different outcomes? - Are there genetic components to psychological disorders, such as depression? - How are genetic diseases passed through family lines? THEORY OF EVOLUTION Charles Darwin explored the concept of inheritance of traits throughout generations in his theory of evolution through natural selection. - The organisms that are better suited for their environment will survive and reproduce, while those that are poorly suited for their environment will die off. Characteristics and behaviors that impact survival and reproduction: - Those that help protect against predators. - Those that increase access to food. - Those that help to offspring alive. ”It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is most adaptable to change.” – Charles Darwin GENETIC VARIATION - The genetic difference between individuals. - Contributes to a species’ adaptation to its environment. - Begins when an egg (containing 23 chromosomes) is fertilized by a sperm (containing 23 chromosomes). Chromosome - long strand of genetic information known as DNA. Deoxyribonucleic acid (DNA) - helix-shaped molecule made of nucleotide base pairs. In each chromosome, sequences of DNA make up genes. Gene - sequence of DNA that controls or partially controls physical characteristics known as traits (eye color, hair color etc). A gene may have multiple possible variations or alleles (a specific version of a gene). - A specific gene may code for hair color and the different alleles of that gene affect what the hair color will be.  Genotype vs phenotype (a) Genotype refers to the genetic makeup of an individual based on the genetic material (DNA) inherited from one’s parents. (b) Phenotype describes an individual’s observable characteristics, such as hair color, skin color, height, and build. (credit a: modification of work by Caroline Davis; credit b: modification of work by Cory Zanker) DOMINANT Vs RECESSIVE ALLELES The majority inheritable traits are controlled by more than just one gene and in such cases, they are known as polygenic traits. Some traits are controlled by one gene. Alleles can be dominant or recessive. In the example below, A is the dominant allele for flower color (purple) and a is the recessive allele for flower color (white). Possession of a dominant allele will always result in expression of that phenotype. This could be inherited from one parent (Aa) or both parents (AA). The phenotype of a recessive allele will only be physically expressed if the person is homozygous for that allele, meaning they inherited a recessive allele from BOTH parents (aa). Heterozygous - consisting of two different alleles (Aa). Homozygous - consisting of two identical alleles (AA/aa). (Credit: B4FA)  The synapse (a) The synapse is the space between the terminal button of one neuron and the dendrite of another neuron. (b) In this pseudo-colored image from a scanning electron microscope, a terminal button (green) has been opened to reveal the synaptic vesicles (orange and blue) inside. Each vesicle contains about 10,000 neurotransmitter molecules. (credit b: modification of work by Tina Carvalho, NIH-NIGMS; scale-bar data from Matt Russell) Reuptake Once an action potential has occurred, excess neurotransmitters in the synapse either drift away, are broken down or are reabsorbed. Reuptake involves moving a neurotransmitter from the synapse back into the axon terminal from which it was released. Reuptake involves moving a neurotransmitter from the synapse back into the axon terminal from which it was released. NEUROTRANSMITTERS Neurotransmitter – chemical messenger of the nervous system. Different neurons release different types of neurotransmitters that have many different functions. Biological perspective - view that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems. Acetylcholine – muscle action and memory. Beta-endorphin – pain and pleasure. Dopamine – mood, sleep, and learning. Norepinephrine – Heart, intestines, and alertness. Serotonin – mood and sleep. DRUGS Psychotropic medication - drugs that treat psychiatric symptoms by restoring neurotransmitter balance. Agonist - drug that mimics or strengthens the effects of a neurotransmitter. Antagonist - drug that blocks or impedes the normal activity of a given neurotransmitter. Agonist/antagonist drugs are prescribed to correct neurotransmitter imbalances. E.g. Parkinson’s disease is associated with low levels of dopamine. Dopamine agonists are often prescribed as one form of treatment. Schizophrenia on the other hand is associated with too much dopamine. Many antipsychotic drugs are therefore dopamine antagonists. THE PERIPHERAL NERVOUS SYSTEM The Peripheral nervous system is made up of two different parts: 1. Somatic nervous system - relays sensory and motor information to and from the CNS. 2. Autonomic nervous system - controls our internal organs and glands and can be divided into the Sympathetic and Parasympathetic nervous systems. - Sympathetic nervous system - involved in stress-related activities and functions; prepares us for fight or flight. - Fight or flight response - activation of the sympathetic division of the autonomic nervous system, allowing access to energy reserves and heightened sensory capacity so that we might fight off a given threat or run away to safety. - Parasympathetic nervous system - associated with routine, day-to-day operations of the body under relaxed conditions. - Rest and restore response – relaxes the body after fight or flight (aka rest and digest). The Sympathetic and Parasympathetic nervous systems complement each other to maintain homeostasis, a state of equilibrium in the body. THE BRAIN AND SPINAL CORD THE BRAIN - Comprised of billions of interconnected neurons and glia. - Bilateral (two-sided). - Can be separated into distinct lobes but all areas interact with one another. THE SPINAL CORD - Delivers messages to and from the brain. - Has its own system of reflexes. - The top merges with the brain stem and the bottom ends just below the ribs - Functionally organized into 30 segments, each connected to a specific part of the body through the PNS. - Sensory nerves bring messages in and up to the brain; motor nerves send messages out to the muscles and organs. - In moments of survival, automatic reflexes allow motor commands to be initiated without sending signals from sensory nerves to the brain first, allowing for very quick reactions. The two hemispheres Lateralization - concept that each hemisphere of the brain is associated with specialized functions. - The left hemisphere controls the right side of the body. - The right hemisphere controls the left side of the body. The surface of the brain is covered with gyri and sulci. A deep sulcus is called a fissure, such as the longitudinal fissure that divides the brain into left and right hemispheres. (credit: modification of work by Bruce Blaus) FOREBRAIN STRUCTURES The forebrain is the largest part of the brain. It contains: - The cerebral cortex – higher level processes - Thalamus - sensory relay - Hypothalamus - homeostasis - Pituitary gland – master gland of the endocrine system - Limbic system – emotion and memory circuit CEREBRAL CORTEX: LOBES OF THE BRAIN Cerebral cortex - surface of the brain that is associated with out highest mental capabilities such as consciousness, thought, emotion, reasoning, language and memory. It can be broken up into four lobes, each with a different function. THE ENDOCRINE SYSTEM A series of glands that produce hormones to regulate normal body functions. The Hypothalamus links the nervous system and endocrine system by controlling the pituitary gland. Pituitary gland – serves as the master gland, controlling the secretions of all other glands. Thyroid – secretes Thyroxine which regulates growth, metabolism and appetite Adrenal gland - secretes hormones involved in the stress response. Gonad - secretes sex hormones, which are important for successful reproduction, and regulate sexual motivation and behavior. Pancreas - secretes hormones that regulate blood sugar. neurotransmitters Major Neurotransmitters and How They Affect Behavior Neurotransmitter Involved in Potential Effect on Behavior Acetylcholine Muscle action, memory Increased arousal, enhanced cognition Beta-endorphin Pain, pleasure Decreased anxiety, decreased tension Dopamine Mood, sleep, learning Increased pleasure, suppressed appetite Gamma-aminobutyric acid (GABA) Brain function, sleep Decreased anxiety, decreased tension Glutamate Memory, learning Increased learning, enhanced memory Norepinephrine Heart, intestines, alertness Increased arousal, suppressed appetite Serotonin Mood, sleep Modulated mood, suppressed appetite This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.  How Do Neurons Communicate and Adapt? A chemical message Varieties of neurotransmitters and receptors Neurotransmitter systems and behavior Adaptive role of synapses in learning and memory A Chemical Message Otto Loewi (1921) – Frog heart experiment; first isolation of a chemical messenger Role of the vagus nerve and neurotransmitter acetylcholine (ACh) in slowing heart rate – Acetylcholine First neurotransmitter discovered in the peripheral nervous system and central nervous system (CNS); activates skeletal muscles in the somatic nervous system (SNS) and may excite or inhibit internal organs in the autonomic nervous system (ANS) The Basis of Neural Communication in a Heartbeat Heart rate changes to match energy expenditure and body’s nutrient and oxygen needs. Loewi – Demonstrated that a frog’s vagus nerve contains a chemical that tells the heart to slow its rate. – Later identified two messenger chemicals: excitatory message (speed up) and inhibitory message (slow down). Neurotransmitters Neurotransmitter – Chemical released by a neuron onto a target with an excitatory or inhibitory effect – Outside the CNS, many of these chemicals circulate in the bloodstream as hormones (have distant targets, action slower than that of a neurotransmitter) Loewi’s discoveries led to the search for more neurotransmitters and their functions. – Actual number of transmitters not known: 60 confirmed, 200 posited Structure of Synapses Second discovery facilitated by the discovery of electron microscope 30 years later (1950s) – Determined neurotransmitters packaged in vesicles at end terminal of axon Chemical synapse – Junction where messenger molecules (neurotransmitters) are released from one neuron to excite or inhibit the next neuron. – Most synapses in the mammalian nervous system are chemical. Chemical Synapse Depicted Parkinson Disease More than 50 years after James Parkinson’s descriptions, French neurologist Jean-Martin Charcot named the condition Parkinson’s disease. Three findings have helped researchers understand its neural basis. – Substantia nigra had degenerated on the side opposite to that showing the symptoms. – Symptoms appeared when the level of dopamine (DA was reduced to less than 10% of normal in the basal ganglia). – In rats, selectively destroyed dopamine-containing neurons produced symptoms of Parkinson disease and confirmed the role of dopamine in a neural pathway connecting the substantia nigra to the basal ganglia. Terms to Learn Structure of Chemical Synapses Synaptic vesicle Presynaptic membrane (presynaptic) (axon terminal) Storage granule Postsynaptic membrane (presynaptic) (dendritic spine) Postsynaptic receptor Synaptic cleft (space (postsynaptic) between) Anterograde synaptic Tripartite synapse transmission Transporter Neurotransmission in Five Steps Anterograde synaptic transmission is the five-step process of transmitting information across a chemical synapse from the presynaptic side to the postsynaptic neuron. 1. The neurotransmitter is synthesized somewhere inside the neuron. 2. It is packaged and stored within vesicles at the axon terminal. 3. It is transported to the presynaptic membrane and released into the cleft in response to an action potential. 4. It binds to and activates receptors on the postsynaptic membrane. 5. It is degraded or removed, so it will not continue to interact with a receptor and work indefinitely. Anterograde Synaptic Transmission Steps 1 and 2: Neurotransmitter Synthesis, Packaging, and Storage Neurotransmitters are derived in two general ways. – Synthesized in the axon terminal Building blocks from food are pumped into cell via transporters, protein molecules embedded in the cell membrane – Synthesized in the cell body According to instructions in the DNA (peptide transmitters) Transported on microtubules to axon terminal Origins of neurotransmitters – Peptide – Lipid – Gaseous – Ion Step 3: Neurotransmitter Release At the terminal, the action potential opens voltage-sensitive calcium (Ca2+) channels. Ca2+ enters the terminal and binds to the protein calmodulin, forming a complex. The complex causes some vesicles to empty their contents into the synapse and others to get ready to empty their contents. – Exocytosis Step 4: Receptor-Site Activation After release, the neurotransmitter diffuses across the synaptic cleft to activate receptors on the postsynaptic membrane. – Transmitter-activated receptors – Ionotropic receptor – Metabotropic receptor – Autoreceptor – Quantum (pl. quanta) Step 5: Neurotransmitter Inactivation After a neurotransmitter has done its work, it is quickly removed from the receptor sites and from the synaptic cleft. Inactivation is accomplished in at least four ways. 1. Diffusion 2. Degradation 3. Reuptake 4. Astrocyte uptake The Versatile Synapse In the nervous system, synapses vary widely, and each type is specialized in location, structure, function, and target. A wide variety of connections makes the synapse a versatile chemical delivery system. Through connections to the dendrites, cell body, or axon of a neuron, transmitters can control the actions of the neuron in various ways. Electrical Synapses Gap junction – Contain connexin proteins on adjacent cell membranes connect to form hemichannels, which allow ions to pass between the two neurons. – Constitute a regulated gate between cells because they can be either open or closed. – Can eliminate brief information flow delay – Allow glial cells and neurons to exchange functions and selectivity for specific size molecules. – Allow for dual chemical and electrical synaptic transmission (mixed synapse).  Excitatory and Inhibitory Messages Excitatory synapse Inhibitory synapse – Typically located on dendrites – Typically located on cell body – Round vesicles – Flat vesicles – Dense material on membranes – Sparse material on membranes – Wide cleft – Narrow cleft – Large active zone – Small active zone Excitatory and Inhibitory Zones Dendritic Spines; Small but Mighty Dendritic spines – Mediate learning. Each spine must be able to act independently, undergoing changes that its neighbors do not undergo. – Provide the structural basis for our behavior, skills, and memories. – Impairments in forming spines characterize some kinds of mental disability, and the loss of spines is associated with the dementia of Alzheimer disease. Evolution of Complex Neurotransmission Systems Chemical transmission may have its origins in the feeding behavior of single-celled creatures. – Digestive juices are secreted onto prey via exocytosis (release of neurotransmitter). – Prey is captured via endocytosis. This process parallels the release of neurotransmitters for communication in more complex creatures. Classes of Neurotransmitters Neurotransmitters can be classified into groups based on their chemical composition. – Small-molecule transmitters – Peptide transmitters – Lipid transmitters – Gaseous transmitters – Ion transmitter Small-Molecule Transmitters Table 5-1 Best-Known and Well-Studied Small-Molecule Neurotransmitters Class of quick-acting Acetylcholine (ACh) neurotransmitters Amines Dopamine (DA) Norepinephrine (NE, or noradrenaline [NA]) Synthesized in the axon Epinephrine (EP, or adrenaline) terminal from dietary nutrients Serotonin (5-HT) and packaged ready for use in Amino acids axon terminals Glutamate (Glu) Gamma-aminobutyric acid (GABA) Glycine (Gly) Histamine (H) Purines Adenosine Adenosine triphosphate (ATP) That’s all Folks! Good LUCK!