PSYC 3510 Behavioral Neuroscience Exam 1 Materials
PSYC 3510 Behavioral Neuroscience Exam 1 Materials PSYC 3510-001
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This 29 page Bundle was uploaded by Erica Britton on Thursday October 13, 2016. The Bundle belongs to PSYC 3510-001 at Auburn University taught by Dr. Barker in Fall 2015. Since its upload, it has received 5 views. For similar materials see Behavior Neuroscience in Psychology (PSYC) at Auburn University.
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Interdisciplinary Perspectives 0819 **Test question Slide 1 Nature vs. Nurture/Motivation Nature of the naturenurture debate has been filled in within the last twenty years by behavioral neuroscience. Specificity of function each inner part of the brain has a specific function rather than the brain as a whole. Hormones have neurotransmitter like functions (addition to our actions are purely chemical). We should be skeptical of this view though!! Bottom line is that our behavior is created by the body/the brain. Slide 2 Minds/Emotion The mind is very different from the brain. Vision and pain are very private processes, so to understand it we can use chemistry. Correlations b/t perception of the mind and aspects vs. what the brain is doing (structure vs. function or body vs. mind to understand this course). The dogs brain produces the dogs mind just like the human brain produces our mind. We use animals to study a lot! They have the brains to allow them to portray emotion unlike the ability to understand why we read things… the brain doesn’t allow this. Slide 3 Why study it? DSM is still far from giving what brain mechanisms are responsible for each disorder. Slide 46 What is it? The four perspectives: Evolutionary why we can study rats and monkeys and place findings on humans Behavioral genetics Anatomical/phys (structure) vs. the Psychological (function) **How do we study the mind? Inference from looking at and studying humans and animal behavior. We can’t just pull out the brain and figure it out, we have to draw the mind out by different tests and questions. It’s interdisciplinary b/c we study it at different levels: ** molar level (intact organism is studied) and molecular level (part of the brain, ppt) We explain things in psychology by talking about how different levels correspond with each other. Slide 7 Why is it interdisciplinary? Because one individual can’t know everything. We’ve got to specialize and have expertise in one level of analysis. We will have to read other literature to learn about other areas of expertise. Like nature vs. nurture, molar and molecular analysis provide more information when we look at them together than alone. Look at sleep and dreams and how it’s split between interdisciplinary studies on Slide 8. Evolutionary/Behavioral Genetic Perspectives What was the human brain designed to do? Essentially we have a very old brain with add on features. Comparative psych comparing behavior of animals / subset of evolutionary psych The data of evolution is no longer bones here and there (what Darwin used), it’s now comparative genetics. Common genes in humans and animals and they’re the genes that are guiding the production of proteins Gene theory/genetics… part of it is genome studies (comparison of genomics with humans and other animals) …adds continuity to the early studies of humans being like animals Changing the nature of a wild nondomesticated fox, took offspring and tamed them and then bred them and kept taming them and breeding until they were fully domesticated (lab breeding studies) BrainBehavior/Physiological Specification of function in the brain Applied medical procedures Suggests that basic neuroscience researchers have very different objectives than medical researchers…but we can use the methodology Lobotomy (20s and 30s) Split brain procedure used for people with seizures, helped to keep them on one side of the brain and affecting the individual less Philosophy of Neuroscience Modern science began in western Europe, hence western way of knowing Following terms on first exam*** Mindbody problem: how are the mind and body related? 0824 / Philosophy of Neuroscience con’t Cartesian dualism from DesCartes / mind and brain/body are separate Our visual world, represented by rays, coming in through the eyes is a sensation of seeing. It takes place in the brain at the pineal gland There is no evidence to support DesCartes beliefs. Today we would look at DesCartes as kind of mentally wrong; he cut apart dogs when the church said no to cutting bodies to understand the sensation of pain. Also thought we were machines; if he could understand the machine he could understand the psychology Our analogy of monism is nice but it’s not evidence. ***40% of our brain can see visual images, gets us closer to understanding it!! Another measure could be visual in addition to magnetic, chemical, etc. Start at 10:00 our psychological experience of those hard science Hard problem of consciousness each psych experience are qualitatively different Second problem is an extension there’s no Rosetta Stone for the transition Know the assumptions as other scientists, and their definitions** Biological (heredity) determinism interacting with a environmental/nurture determinism to make the human mind and behavior. Bio + Environmental Hard or soft determinism *** What is what? Soft is neither here nor there and doesn’t address anything…. Can’t deal with hard determinism Hard means there is no free will because each behavior is determined by the past… Everything you decide at the point of time you decide is influenced by previous conditions o BF Skinner made a case for why there is no free will Barker’s conclusion: free will vs. determinism will be debated for a long time!!!! Mechanism is similar to biological determinism…. Many scientists that believe reductionism is not the best way to explain science* Emergence opposite of reductionism. Child development in the brain, continuously changing and setting up new memories which is the reorganization of neurons, pruning occurs (cell/neuron death as they are unused while others are) Barkers conclusion: emergence is a reasonable assumption that will require evidence that is not yet specifiable Free will is engrained in our culture so it is very hard to think differently than it!! Hard determinism seems more realistic to think about Methodology I Two methods: correlational method and experimental Correlational method taking two independent measurements and doing a correlational statistic to look at the degree of the relationship that exists between them. Not the strongest form of evidence o More reading and parental involvement, the more you find in the temporo occipitalparietal junction, compared to kids that were not read to by parents. When you’re visualizing something, you have a part of the brain that’s involved (storytelling) Chapter One / PowerPoints 23 Why do people behave as they do? We ask this a lot in neuroscience. We ask how nature (genes) and nurture (experience and learning) affect who we are. Behavioral NSC has answered the nature side of the debate within the last 20 years. We can use nonhuman animals, because like us their brain produces a mind, to study our behavior as well as chemistry to understand the relationships between our brain and behavior. We also ask questions about motivation, emotions, etc. We rely heavily on chemistry because a lot of psychological processes like pain, or even physical like vision, are private. We have to infer. Bottom line, though behavior is created by the brain Why do we study behavioral neuroscience? To understand how the brain works. More specifically, what brain mechanisms allow for mindstuff. The DSM still has a long way to go in terms of neural mechanisms and disorders… but one day! Behavioral neuroscience The study of the mind and behavior of humans and other animals. Four perspectives Behavioral genetic, evolutionary, anatomical/physiological, psychological Define mind, behavior, and interdisciplinary. Mind is the psychological experiences of humans and animals Behavior is how we act or respond in an environment. Interdisciplinary means we can study behavioral neuroscience at different levels. Interdisciplinary studies (levels, how we use it) We can study at the molar level, which is an intact organism, or at a molecular level, which gets down to the anatomical or electrochemical features of something. Remember the sleep example we can study sleep and dreams… or just brain waves during sleep… or anatomical aspects of sleep in our brain… down to neurotransmitters Perspective 1 Evolutionary What was the human brain designed to do? Essentially we have an old brain with some add on features. What do we use now instead of fossils, like Darwin used? We use comparative genetics and psychology. We can look at how similar our protein structures are to other animals and therefore study them to infer knowledge about us. Perspective 2 Behavioral genetic genes provide recipes for unique brains Gene theory/genetics/genome studies we can use gene theory and genetics to study NSC. Genome studies let us also compare us to other nonhuman animals Lab breeding studies we can look at the interaction of genes and environmental influence. Ex: taming wild foxes and breeding them until tame Perspective 3 Psychological Some examples motivation, emotion, consciousness, learning, memory Perspective 4 Anatomical/physiological Some examples tracking eye movements in schizophrenics… specification of function!! Selfstimulation in rats Applied medical procedures differing from NSC objectives 1. Prefrontal lobotomy was used in the 20s and 30s we would split the front and back of the brain by disrupting connective tissue 2. Splitbrain procedure is still used today. We cut the corpus colossum, severing connections between hemispheres. This helps patients with epilepsy or seizures by restricting seizures to one side of the brain 3. Currently used electroconvulsive therapy used to help treat depression What are ways of knowing? Examples? Different ways to understand human behavior. Math, reason, intuition, science, and art are some examples… even music What characterizes the “Western” way of knowing? Western meaning Europe, their ways of knowing are more scientific and empirical. We use a systematic method to make observations rather than following, say, the church. Modern, scientific Science as a way of knowing what about nonscientific beliefs? Science as a way of knowing is definitely the best way to approach things. We can give the why and how of everything while others can’t. Nonscientific beliefs aren’t bad! They’re beliefs… and they’ll probably never go away. Mindbody problem How the mind and the body/brain can relate to each other Historic solutions Aristotle suggested dualism, that the mind and the body are two separate entities. Rene Descartes furthered this by coining the term Cartesian dualism, that the two are separate entities but they interact at the pineal gland. Pineal gland b/c it was the only structure he could find that wasn’t bilateral.. also small and circular (symbolic) Modern solutions and problems Monism suggest that mind and body are two separate forms of the same entity. Problems hard problem of consciousness, that every conscious process is unique and that there is no rosetta stone for this… we can’t translate all these to fit to each persons standards Assumptions we make to study NSC 1. Determinism that every event has a cause and that cause can be ascertained a. Specifically, our behavior is caused by a combination between biological determinism and environmental determinism b. Hard determinism there is no free will because everything is determined by the past c. Soft determinism that physical processes have cause, but mental processes do not. Doesn’t really help us in this case 2. Mechanism related to biological determinism… the means by which an effect is produced a. Specifically, genes/cells/brains/bodies are the means of our behavior 3. Reductionism way of explaining behavior by reference to more molecular events. a. Seeing color because we have retinas or sadness depends on serotonin levels b. Not highly looked upon 4. Emergence appearance of new properties in the course of development that could not be foreseen!!! a. Examples human mind emerged from the unique organization of an increasingly larger and diff. organized brain b. Reasonable but we need evidence that is not specifiable right now Assumptions from outsiders? Those are fine too! Poets will look at behavior differently and that’s ok. We’re just taking another approach Neuroscience study of the nervous system Biopsychology study of biology of behavior… D.O. Hebb The Organization of Behavior in 1949. Three types of research 1. Human vs. nonhuman a. Human is cheaper and more applicable, but nonhuman have less ethical constraints, comparative aspects, and because their brains are more simple, research shows more fundamental principles 2. Experimental vs. nonexperimental a. Experimental used for causation. Betweensubjects designs use groups for each level of the IV while withingroups designs use one group for all levels. b. Non experimental, can be quasiexperimental where we study something in the real world. It’s more applicable and used when there are ethical constraints IRL but we can’t control confounding variables. Case studies offer in depth knowledge but generalizability is a huge problem 3. Applied vs. pure a. Pure research is curiosity. It is better from the viewpoint of a scientist but government is skeptical of funding research with no immediate benefit to the public b. Applied is to benefit the general public. It’s more widely accepted but we sometimes skip basic understanding just to publish Six divisions of biopsychology 1. Psychopharmacology 2. Neuropsychology 3. Physiological psychology 4. Psychophysiology 5. Comparative psychology 6. Cognitive neuroscience Different between physiological psychology and psychophysiology? Psychophysiology studies the relation between physiological activity and psychological process in human subjects (remember… the relation… psychophysio… close together). Physiological psychology studies the neural mechanisms of behavior Converging operations We can combine different perspectives so that the weaknesses of one division will be compensated for by the strengths of another. Chapter Five / PowerPoint 4 What is the evidence/basis for what we know about brain functioning? Scientific knowledge comes from: inductive (specific observations to general) and deductive (theories to specific) empirical methods experimental and observation These all encompass the scientific method. Steps of scientific method: curiosity, hypothesis, design, perform, analyze, validate, publish Correlation methods fMRI functional magnetic resonance imaging, shows active areas of the brain active areas will use more oxygen and when the oxygenated blood accumulated it will show on the image because of its magnetic properties, BOLD (blood oxygen level dependent) signal Advantages over PET higher spatial resolution image, shows function and structure, can be 2D or 3D, nothing is injected Experimental methods IV / DV change independent variable, measure dependent variable Within subject design – when one group receives all IV treatment levels / within subject control group receives IV treatments, measure taken before and after Between subject design IV treatment levels split one per group / between subject control group group that receives same conditions as experimental group except for the IV Remember corpus colossum example Noninvasive methods pt. 1 brain imaging 1. CAT/CT Scan computer assisted tomography or computerized tomography can show structure of brain with xrays to help visualize the brain and other internal structures 2. MRI magnetic resonance imaging creates high resolution images made from the measurement of waves that hydrogen atoms emit when they are activated by radio frequency waves in a magnetic field a. More clear than CT b. Colorcoded c. High spatial resolution (ability to detect and represent differences in spatial location) 3. fMRI limitations low temporal resolution, slow blood flow 4. PET Scan positron emission tomograph / injects radioactive substance to carotid artery that feeds the brain… active cells take up 2DG and the image shows levels of radioactivity, indicated by color, in the brain a. Uses: 2deox glucose or 2DG 5. Contrast xrays / angiography Contrast xrays involve injecting a substance that absorbs xrays either less or more than the surrounding tissue to heighten the contrast. Angiography uses the infusion of a radioopaque dye into artery. 6. MEG Scan magnetoencephalogram measures changes in magnetic fields on the surface of the scalp produced by changes in neural activity Noninvasive methods pt. 2 recording 1. EEG electroencephalogram is a measure of the gross electrical activity in the brain. Some EEG waves are associated with particular states of consciousness 2. ERP/EP event related potentials or evoked potentials measure brain waves after a brief auditory or visual stimulation 3. EMG tension in muscles measure by taping two electrodes to the surface of the skin over muscle of interest. 4. EOG electrooculogram measures eye movement 5. SCL skin conductance levels, skin produces electricity SCL measure background level a. SCR measures skin conductance response.. transient changes 6. ECG/EKG electrocardiogram measures electric signals of heart beats a. Plethysmograph measures change in the volume of blood in a particular part of the body. CHAPTER 1 BIOPSYCHOLOGY AS A NEUROSCIENCE Neuroscience is the scientific study of the nervous system. It is comprised of several related disciplines; one being biopsychology. The chapter is split into seven sections and each section will characterize the neuroscience of biopsychology in a different way. Four themes of the book: thinking creatively, clinical implications (both learning from diseased brains and applying research to treatment), the evolutionary perspective (specifically comparative approaches), neuroplasticity (the fact that the brain is a changeable organ that grows in response to genes and experiences). 1.1 WHAT IS BIOPSYCHOLOGY? Biopsychology is the scientific study of the biolthy of behavior. Biopsychology did not develop into a major neuroscientific discipline until the 20 century when D.O. Hebb published The Organization of Behavior in 1949. 1.2 WHAT IS THE RELATION BETWEEN BIOPSYCHOLOGY AND THE OTHER DISCIPLINES OF NEUROSCIENCE? Biopsychologists are unique due to their knowledge of behavioral orientation and its’ methods of research that they can bring to the table. Biopsychology pulls information from neuroanatomy, neurochemistry, etc. 1.3 WHAT TYPES OF RESEARCH CHARACTERIZE THE BIOPSYCHOLOGICAL APPROACH? Human vs. nonhuman subjects: Humans are easier to study because they are: cheaper; most lab animals must meet very high standards and are therefore very expensive we have actual human brains (our brains, however, only differ in quantitative measures like size, so the same principles can be applied). Nonhuman animals have three advantages in research: their brains and behavior are simpler, revealing more fundamental brainbehavior interactions comparative approaches can give us insight to an area like cerebral cortex when we can look at an animal with and an animal without one ethics are not as constraining on animals Experimental vs. nonexperimental We use experimental designs to study causation. We can either use different groups of subjects for each condition, called betweensubjects designs, or we can test the same group of subjects under each condition, called withinsubjects design. Know IV, DV, and confounding variables. Two nonexperimental ways to research are: Quasiexperimental studies studies of groups of subjects who have been exposed to the conditions of interest in the real world. o Usually used when physical or ethical problems arise, making it hard to assign subjects to certain conditions o They are not true experiments because they are not able to control confounded variables Case studies studies that focus on a single case or subject o They offer more indepth information o Major problem with generalizability Pure vs. applied Pure research is research motivated primarily by the curiosity of the research and done solely for the curiosity of the researcher. Applied research is research intended to bring about benefit to the general public. Scientists think that pure research could potentially be more practical than applied research. Why? When we use applied research, we are immediately trying to the application process before we gain a basic understanding. Many research programs use both approaches. Pure research is more vulnerable to vagaries of political regulation because politicians and the general public have difficulty understanding why research of no immediate practical benefit should be supported. 1.4 WHAT ARE THE DIVISIONS OF BIOPSYCHOLOGY? The purpose of this section is to more clearly understand the following six major divisions of biopsychology: 1. Physiological psychology division that studies the neural mechanisms of behavior through the direct manipulation of the brain in controlled experimentssurgical and electrical methods of brain manipulation are most common. 2. Psychopharmacology similar to above, but focuses on the manipulation of neural activity and behavior with drugs. 3. Neuropsychology the study of the psychological effects of brain damage in human patients. Mainly uses quasiexperiments and case studies. The cerebral cortex is most likely damaged by accident, so a lot of neuropsychology studies it. 4. Psychophysiology studies the relation between physiological activity and psychological processes in human subjects. Uses noninvasive procedures like measuring brain activity from the scalp using electroencephalogram (EEG), or muscle tension, eye movement, etc. Ex: schizophrenics have difficulty smoothly tracking a moving object like a pendulum 5. Cognitive neuroscience studies the neural bases of cognition (higher intellectual processes such as thought, memory, etc.). Newest division of biopsychology, focuses on human subjects and uses noninvasive procedures. Ex: functional brain imaging 6. Comparative psychology deals with the biology of behavior rather than specifically neural mechanisms of behavior; compares behavior of different species in order to understand evolution, genetics, and adaptiveness of behavior. Uses lab and ethological research, the study of animal behavior in its natural environment. Evolutionary psychology and behavioral genetics fall under comparative psychology. 1.5 CONVERGING OPERATIONS: HOW DO BIOPSYCHOLOGISTS WORK TOGETHER? Biopsychologists use converging operations combined approach using multiple different divisions to understand a single problem. The weaknesses of one division are compensated in the strength of another division. Ex: combining neuropsychology and physiological psychology. Ex: using neuropsychology and physiological psychology to understand the psychological effects of damage to the human cerebral cortex. Neuropsychology advantage: deals directly with human patients Neuropsychology weakness: focuses on humans and therefore precludes experiments Physiological psychology advantage: able to use experimental methods on nonhuman animals Physiological psychology weakness: relevance of nonhuman research to human neuropsychological deficits is always questionable 1.6 SCIENTIFIC INFERENCE: HOW DO BIOPSYCHOLOGISTS STUDY UNOBSERVABLE WORKINGS OF THE BRAIN? Scientific inference empirical method that Biopsychologists fundamentally use to study the unobservable. We can measure key events that we can observe and then use these measures as a basis for logically inferring the nature of events that we can’t see. 1.7 CRITICAL THINKING ABOUT BIOPSYCHOLOGICAL CLAIMS The first step to creatively thinking about information is spotting the weaknesses of existing ideas and the evidence on which they are based, called critical thinking. Identifying these weaknesses is a major stimulus for adopting new approaches. The first step in judging the validity of a scientific claim is looking at whether the research was published in a reputable scientific journal. CHAPTER 5 THE RESEARCH METHODS OF BIOPSYCHOLOGY Part 1: Methods of studying the nervous system 5.1 METHODS OF VISUALIZING AND STIMULATING THE LIVING HUMAN BRAIN Xrays are essentially useless for visualizing the brain. Xray beams pass through an object and then onto a photographic plate. Molecules through which the beam passes absorb some of the radiation; thus, only the unabsorbed portions of the beam reach the photographic plate. In the human brain, it’s overlapping structures that are very similar to one another when absorbing X rays, it doesn’t produce an image of the structures it passed through. Contrast Xray techniques involve injecting a substance that absorbs Xrays either less or more than the surrounding tissue. The injected substance will heighten the contrast. One technique is the cerebral angiograph, which uses the infusion of a radioopaque dye into a cerebral artery to visualize the cerebral circulatory system during Xrays. Most useful for localizing vascular damage and the displacement of blood vessels (indication of a tumor) Computed tomography changed the study of the human brain when it was introduced in the 70s. A computed tomograph (CT) is a computerassisted Xray procedure that helps to visualize the brain and other internal structures of the body. Cerebral computed tomography works by putting an Xray beam on one side and an X ray detector on the other that rotate around each other and take multiple pictures. The pictures together create a 3D representation. Magnetic resonance imaging (MRI) is a procedure that creates highresolution images made from the measurement of waves that hydrogen atoms emit when they are activated by radio frequency waves in a magnetic field. More clear than CT Colorcoded, can be 2D or 3D High spatial resolution (the ability to detect and represent differences in spatial location) Positron emission tomograph (PET) was the first brain imaging technique to show brain activity rather than structure. Commonly, 2deox glucose (2DG) is injected into the carotid artery, that feeds into the brain. Active cells take up the 2DG and the PET scan is an image of the levels of radioactivity, indicated by color, coding in the brain. The most popular tool in cognitive neuroscience is the functional MRI (fMRI) that produces images representing the increase in oxygen flow in the blood to active areas in the brain. It’s possible because active areas of the brain take up more oxygenated blood allowing the oxygenated blood to accumulate in active areas and oxygenated blood has magnetic properties The signal the fMRI records is the BOLD signal (the bloodoxygenleveldependent signal). Four advantages over PET: o Nothing is injected o Shows structural and functional o Higher spatial resolution o Produces 3D images over entire brain, not just a horizontal image Two disadvantages: o BOLD signals and neural activity do not have an easy inference. The relationship is complex and variable o fMRI technology is too slow to capture neural responses Magnetoencephalograph (MEG) is another technique used. It measures changes in magnetic fields on the surface of the scalp that are produced by changes in underlying patterns of neural activity. Advantage over fMRI is its temporal resolution (ability to record fast changes in neural activity) PET, fMRI, and magnetoencephalography have helped cognitive neuroscientists but they can only show a correlation between brain and cognition, but they can’t prove the brain activity caused the cognitive activity. Transcranial magnetic stimulation (TMS) is a technique for affecting activity in an area of the cortex by creating a magnetic field under a coil positioned next to the skull. The magnetic stimulation temporarily turns off part of the brain while the effects of the disruptions are assessed. It’s level of safety, depth of effect, and mechanisms of neural disruption are still questioned but it helps us to determine causation in addition to correlation. 5.2 RECORDING HUMAN PSYCHOPHYSIOLOGICAL ACTIVITY The following measures are used to record physiological activity from the surface of the human body, or psychophysiological recording methods. One measures brain activity, two the somatic nervous system activity, and two the autonomic nervous system activity 1. An electroencephalogram (EEG) is a measure of the gross electrical activity of the brain. It’s useful because some EEG wave forms are associated with particular states of consciousness or particular types of cerebral pathology. a. Accompanying EEG waves with certain psychological events can tell more than just the background EEG signal. We call these eventrelated potentials (ERP). A common ERP is the sensor evoked potential the change in cortical EEG signal that is elicited by the presentation of a sensory stimulus. 2. Tension in muscles is used as an indicator of physiological arousal. It’s measured using an electromyograph. EMG activity is recorded between two electrodes taped to the surface of the skin over the muscle of interest. 3. The technique for recording eye movement is called electrooculograph, and the recording is called an electrooculogram (EOG). 4. Emotional thoughts and experiences are associated with increases in the ability of the skin to conduct electricity. Skin conductance level (SCL) is an index that measures the background level of SC with a particular situation. Skin conductance response (SCR) measures the transient changes. 5. Cardiovascular activity and emotion are also related. The cardiovascular system has two parts: the blood vessels and the heart. Three measures of cardiovascular activity are heart rate, arterial blood pressure, and local blood volume. a. Heart rate An electrocardiogram (ECG/EKG) measures electrical signals associated with each heartbeat. b. Blood pressure expressed as a ratio of systolic (peak during heart contraction) over diastolic (minimum pressure during relaxation) c. Blood volume a plethysmograph measures changes in the volume of blood in a particular part of the body. 5.3 INVASIVE PHYSIOLOGICAL RESEARCH METHODS Invasive techniques used on lab animals fall into three categories: lesion methods, electrical stimulation methods, and invasive recording methods. Used by physiological psychologists Stereotaxic surgery uses experimental devices precisely positioned in the depths of the brain. You need an atlas and an instrument. A stereotaxic atlas locates brain structures like a geographic atlas, however it has shows three dimensions of the brain. The stereotaxic instrument is made up of the head holder and the electric holder (that is inserted). Lesion methods remove/damage/destroy a part of the brain so they can carefully assess the functions of that structure by watching behavior. Aspiration lesions when a lesion is made in an area of cortical tissue that is accessible to the surgeon, aspiration is used the cortical tissue is suctioned out through a fine tipped handheld glass pipette. Radiofrequency lesions small subcortical lesions can be made by passing radio frequency currents through the target tissue, destroying the tissue by heat. Knife cuts sectioning or cutting is used to eliminate conduction in a nerve or tract. Cryogenic blockade alternative to destructive lesions; cryogenic blockades essentially freeze neurons and keep them firing until they warm up again. Also called reversible lesions Electrical stimulation helps to understand the function of a neural structure by electrically stimulating it. The stimulation is delivered through a bipolar electrode. This is an effective tool because it produces behavioral effects, usually opposite to those produce by a lesion. The four invasive electrophysiological recording methods are: Intracellular unit recording records fluctuations in ONE neuron’s membrane potential; performed on chemically immobilized animals (it’s hard to keep the tip of a microelectrode still when an animal is moving) Extracellular unit recording records the action potentials of ONE neuron through a microelectrode whose tip is positioned in the extracellular fluid next to it each time the neuron fires, there’s an electrical disturbance and the blip is recorded at the electrode tip. It gives information on the firing of a neuron but not membrane potential. Multipleunit recording a small electrode records the action potentials of MULTIPLE nearby neurons. These are added up and plotted on a graph per unit in time. Invasive EEG recording a large implanted electrode picks up general changes in electrical brain activity. The EEG signal is not related to neural firing in any obvious way. 5.4 PHARMACOLOGICAL RESEARCH METHODS The following section shows you how psychopharmacologists manipulate and record from the brain using chemical methods. Drugs can be administered in the following ways: Fed to the subject Injected into the stomach through a tube Injected hypodermically into various places (peritoneal cavity, large muscle, etc.) The problem with administering drugs is that they do not readily pass through the bloodbrain barrier. An effective manner that overcomes this barrier is to give the drug in small amounts through a cannula, or a fine hollow tube, into the brain. Surgical, electrolytic, and cryogenic lesion effects are hard to interpret because they affect all neurons in the target area. We can make selective lesions by injecting neurotoxins (neural poisons) that have an affinity for certain components of the nervous system. Ex: when you inject 6hydroxdopamine (6OHDA), it is only taken up by neurons that release norepinephrine or dopamine, leaving other neurons at the target area undamaged. Two techniques used to measure the chemical activity of the brains of lab animals: The 2deoxyglucose technique entails injecting radioactive 2DG and then putting a lab animal in a test situation that holds interest to the animal. Because 2DG is similar to glucose, the source of energy, neurons active during the activity will absorb it but not metabolize it. The subject is killed and the brain is removed and sliced. The slices are subjected to autoradiograph, coated with a photographic emulsion, stored in the dark, and then developed like film. Areas that absorbed 2DG will appear as black spots on the slide. Cerebral dialysis measures extracellular concentration of a specific neurochemical in behaving animals by implanting a tube with a short semipermeable section. This section is positioned in the structure of interest so that extracellular chemicals will diffuse into the tube. Once in the tube, they can be collected for later analysis or a chromatograph (device for measuring chemical constituents of liquids). When trying to find out where a neurotransmitter is located in the brain, we use two techniques that involve exposing brain slices to a labeled ligand (the ligand of a molecule is another molecule that binds to it). Immunocytochemistry used to locate particular neuroproteins by labeling their antibodies with a dye or radioactive element and then exposing slices of brain tissue to the labeled antibodies. Regions of dye in the brain slices mark the locations of the target neuroproteins. Can be used to locate neurotransmitters by binding to their enzymes. In Situ Hybridization used to locate peptides and other proteins. Takes advantage of the fact that all peptides and proteins are transcribed from sequences of nucleotide bases on strands of messengerRNA. Hybrid strands of mRNA with the complementary base sequences are artificially created and used to locate the neurons that release the target neuroprotein. 5.5 GENETIC ENGINEERING Gene knockout techniques work as they sound, they create organisms that lack a particular gene (they “knock out” a certain gene). Gene knockout studies are used to clarify the neural mechanisms of behavior. Ex: creating melanopsin knockout mice (missing melanopsin) to study the role of mel. in regulating the lightdark cycles that control circadian rhythms of bodily function. It appears to contribute to the control of circadian rhythms by light, but it is not the only factor. This is typical of gene knockout studies. Gene replacement techniques show that it is possible to replace one gene with another. Pathological genes from human cells can be inserted in other animals, like mice. Mice that contain the genetic material of another species are called transgenic mice. Another GRT technique replaces one gene with an identical one except for the addition of a few bases that can act as a switch, turning the gene off or on in response to certain chemicals. Green fluorescent protein (GFP) is a protein that exhibits bright green fluorescence when expose to blue light; it became useful in the early 90s when its gene was identified and cloned. Now the general strategy is to active the GFP gene in only the particular cells so that they can be readily visualized either by inserting the GFP gene in only target cells or by introducing it to all cells but expressing it only in the target cells. In the late 90s, an advancement was made by making minor alterations to the GFP gene, resulting in the synthesis of proteins that fluoresced in different colors. Each neuron produced different amounts of three proteins, giving it a distinctive color. Now we can trace the pathways of neural axons to their destinations, called brainbow (called this b/c it’s very colorful). Part 2: Behavioral research methods of biopsychology Now we turn from methods used to study the nervous system to methods that deal with the behavioral side of biopsychology. The major objectives are to control, simplify, and objectify. A single set of procedures developed for the investigation of a particular behavioral phenomenon is a behavioral paradigm. Each paradigm usually has a method for producing a behavior and a method for objectively measuring it. 5.6 NEUROPSYCHOLOGICAL TESTING While a neurologist will assess simple sensory and motor functions in a patient, a neuropsychologist will assess the more subtle changes in perceptual, emotional, motivational, or cognitive functions. Neuropsychological testing is time consuming and only prescribed to a small portion of braindamaged patients, but has three important ways of helping: Assisting in the diagnosis of neural disorders Serving as a basis for counseling and caring for the patients Providing a basis for objectively evaluating the effectiveness of the treatment and the seriousness of its side effects Psychological testing has evolved through the following three distinct phases: Singletest approach before the 1950s, tests were designed to detect the presence of brain damage. Specifically, the goal was to discriminate between patients with problems stemming from structural brain damage OR functional brain damage. This didn’t work as no single tests could be sensitive to all the varied and complex symptoms that could occur. Standardizetestbattery approach became the predominant approach in the 1960s. Instead of a single test, they involved standardized batteries (sets) of tests. An aggregate score below the designated cutoff leads to a diagnosis of brain damage. It can successfully discriminate between neurological patients and healthy patients, but they can’t discriminate between neurological and psychiatric patients. Customizedtestbattery approach today the objective of neuropsychological testing is not merely to identify patients with brain damage, but to characterize the nature of the psychological deficits of each braindamaged patient. We administer a common battery of tests and then, depending on the results, we select a series of tests customized to each patient. o These tests differ from earlier tests in three ways: (1) newer tests are designed to measure aspects of psychological function that have been spotlighted by modern theories, (2) the interpretation of the tests results often does not rest entirely on how well the patient does, and (3) the customizedtestbattery approach requires more skill and knowledge on the part of the neuropsychologist Tests of the Common Neuropsychological Test Battery Intelligence an IQ tests is nearly always included. The Wechsler Adult Intelligence Scale (WAIS) is the most popular test. It can help to interpret the results of subsequent tests. Memory the WAIS assesses general knowledge and the digit span subtest identifies the longest sequence of random digits that a patient can repeat correctly 50% of the time (avg. is 7). These two forms of memory are least likely to be disrupted by brain damage, however. Language WAIS can assess language. If a patient is not taking the WAIS, the token test can be used. It involved two different shapes, two different sizes, and five different colors. Lateralization of language the hemisphere of the brain that language is dominant in varies. A test to assess this is included in the common test battery. Two specific tests are the sodium amytal test (injects the anesthetic sodium amytal into either the left or right carotid artery in the neck that anesthetizes the ipsilateral, same side, and leaves the contralateral, opposite side, largely unaffected) and the dichotic listening test (three digits are presented to one ear at the same time that three different digits are presented to the other ear… subjects report more of the digits heard by the ear contralateral to their dominant hemisphere) Tests of the Specific Neuropsychological Function Memory four fundamental questions about memory impairment are asked after discovering that it exists o Does it involve shortterm, longterm, or both? o Are any deficits in longterm memory anterograde (memories affected after the damage), retrograde (memories affected before the damage), or both? o Do any deficits in longterm memory involve semantic memory (knowledge of the world) or episodic memory (personal experiences)? o Are any deficits in longterm memory deficits of explicit memory (memories of which the patient is aware and can express verbally), implicit memory (memories demonstrated by improved performance of the patient without the patient being conscious), or both? Repetition priming tests are able to assess this pattern. Language tests are further administered to clarify the nature of the problem. For example, whether the nature of the problem is with phonology, syntax, or semantics. Braindamaged patients may have one of these but not the others, so testing speech problems must include tests of each capacity. We can use the Wisconsin Card Sorting Test to assess damage to the frontal lobe. The test involves specific cards and the patient is asked to sort them. The examiner will let the patient know when they are sorting them incorrectly, however patients with damage to their frontal lobes continue to sort on the basis of one sorting principle for 100 or more trials after it has become incorrect. 5.7 BEHAVIORAL METHODS OF COGNITIVE NEUROSCIENCE Cognitive neuroscience is predicated on two related assumptions. The first is that each complex cognitive process results from the combined activity of simple cognitive processes called constituent cognitive processes. The second is that each CCP is mediated by neural activity in a particular area of the brain. A main goal of cognitive neuroscience is to identify the parts of the brain that mediate various CCP. The pairedimage subtraction technique has become one of the key behavioral research methods. Using a simple PET scan wouldn’t be effective because much of the activity recorded would be associated with other processes. The pairedimage technique involves obtaining PET or fMRI images during several different cognitive tasks. The tasks only differ in a single constituent cognitive process. The brain activity can be estimated by subtracting the activity in the image associated with one of the two tasks from the activity in the image associated with the other. Interpretation of difference images is complicated because there is still substantial activity going on when we sit quietly and let our minds wander. This is called the brain’s default mode, which is made up of the default mode network (medial and lateral parietal cortex, medial frontal cortex, and lateral temporal cortex). Another difficulty results from the noise associated with random cerebral events that occur during the tests. The noise created can be reduced with a technique called signal averaging. 5.8 BIOPSYCHOLOGICAL PARADIGMS OF ANIMAL BEHAVIOR Behavioral paradigms used can be split into three categories: speciescommon behaviors, traditional conditioning paradigms, and seminatural animal learning paradigms. Paradigms for assessment of SpeciesCommon Behaviors Behaviors displayed by virtually all members of a species, or at least by all those of the same age and sex, are called species common behaviors. Some examples are grooming, eating, and copulating. The openfield test places a rat in a large, barren chamber and records its activity. It is common to count the number of boluses (pieces of excrement) dropped by an animal. The colonyintruder paradigm observes encounters between the dominant male rat and a smaller male intruder. The elevated plus maze is also a test of defensiveness that is used to study in rats the anxiety0reducing effects of drugs. The measure of anxiety is the proportion of time the rats spend in the protected closed arms rather than on the exposed arms. Sexual behavior is studied mostly by the copulatory act itself. Common measures of male rat sexual behavior are the number of mounts required to achieve intromission (male inserting his penis into female’s vagina), the number of intromissions required to achieve ejaculation, and the interval between ejaculation and the reinitiation of mounting. The most common measure of female rat sexual behavior is the lordosis quotient (the proportion of mounts that elicit lordosis, the stance and posture that shows the female is receptive to the male mount). Traditional conditioning paradigms learning paradigms play a major role in biopsychological research for three reasons… (1) learning is a phenomenon of primary interest to psychologists, (2) they provide an effective technology for producing and controlling animal behavior, and (3) it is possible to infer much about the sensory, motor, motivational, and cognitive state of an animal from its ability to learn and perform various responses. The Pavlovian conditioning paradigm pairs an initially neutral stimulus (conditional stimulus) with an unconditional stimulus a stimulus that elicits an unconditional (reflexive) response. As a result of these pairings, the conditional stimulus will elicit a conditional response. In the operant conditioning paradigm, the rate at which a voluntary response is emitted is increased by reinforcement or decreased by punishment. o The selfstimulation paradigm allows animals to press a level and deliver electrical stimulation to particular sites in their own brains, usually pleasure centers support selfstimulation. Seminatural animal learning paradigms these are designed to mimic situations that an animal might encounter in its natural environment. Development of these stemmed in part from the assumption that forms of learning tending to benefit an animal’s survival in the wild are likely to be more highly developed. A conditioned taste aversion is the avoidance response that develops to tastes of food whose consumption has been followed by illness. This ability to readily learn the relationship between a taste and the subsequent illness increase their chances of survival. o The discovery of conditioned taste aversion challenged three widely accepted principles of learning: (1) that animal conditioning is always a step by step process (taste aversions can be learned in a single trial), (2) showed that temporal contiguity is not essential for conditioning (rats acquire taste aversions even when they aren’t sick until several hours after eating), and (3) it challenged the principle of equipotentiality the view that conditioning proceeds in the same manner regardless of what you’re investigating (rats appear to have evolved to readily learn associates between tastes and illness; it takes great difficulty to learn relations between color of food and nausea) The radial arm maze was designed to study spatial abilities. It is an array of arms, usually eight or more, radiating from a central starting area. At the end of each arm is a food cup, which may or may not be baited. Another design used to study spatial abilities is the Morris water maze. The rats are placed in a circular, featureless pool of cool milky water, in which they must swim until they discover the escape platform. It is useful for assessing the navigation skills of brain lesioned or drugged animals. In conditioned defensive burying, rats receive a single aversive stimulus (a shock, air blast, or noxious odor) from an object mounted on the wall of the chamber just above the floor, which is littered with bedding material. After a single trial, most rats learn that the test object is a threat and responds by flinging bedding material at it with its head and forepaws. This design is used to study the neurochemistry of anxiety. CHAPTER 2 EVOLUTION, GENETICS, AND EXPERIENCE We are the intellectual product of a Zeitgeist, the general intellectual climate of our culture. 2.1 THINKING ABOUT THE BIOLOGY OF BEHAVIOR: FROM DICHOTOMIES TO INTERACTIONS We tend to exclusively think about our existence in dichotomies: good or bad, right or wrong, etc. When questioning our behavior, our thinking in terms of dichotomies is illustrated by the two questions we ask: 1. Is our behavior physiological or psychological? 2. Is it inherited or is it learned? The conflict of whether we are physiological or psychological rose to prominence following the th Dark Ages, in response to a 17 century conflict between science and the Roman Church. When the Dark Ages occurred, many people turned to art and commerce (the Renaissance). Renaissance followed, discontent following the church, started to study things by directly observing them giving birth to modern science. Rene Descartes, a French philosopher, resolved the conflict with his philosophy that gave one part of the universe to science and the other part to the Church. He argued that the universe is composed of two elements: physical matter and the human mind. This philosophy became known as Cartesian dualism and reiterated the fact that the human brain and the mind are separate entities. We also have conflict in thinking about the development of behavioral capacities and whether it is inherited or if we acquire them through learning, commonly called the naturenurture issue. Early North American experimental psychologists were committed to the nurture side of things, while Europe was focused on ethology, the study of animal behavior in the wild, and therefore sided with instinctive behaviors or the nature side of the debate. Problems with thinking about the biology of behavior in terms of traditional dichotomies There are two lines of evidence against physiologicalorpsychological thinking: 1. Even the most complex psychological changes, like changes in selfawareness, can be produced by damage to, or stimulation of, parts of the brain a. Oliver Sacks’s The Case of the Man Who Fell Out of Bed, asomatognosia 2. Some nonhuman species, particularly primate species, possess abilities that were once assumed to be purely psychological and thus purely human a. G.G. Gallup’s research showing selfawareness in chimpanzees using mirrors Lines of evidence against the natureornurture thinking: 1. Factors other than genetics and learning were shown to influence behavioral development, like fetal environment, stress, nutrition. This changed the dichotomy from “genetic factors or learning” to “genetic factors or experience” 2. It was argued that behavior always develops under the combined control of both nature and nurture, not under the control of one or the other. People, incorrectly, started to think in terms of “How much of it is the result of genetics?” and “How much of it is the result of experience?” a. We should be looking at nature and nurture from an interactive perspective rather than an additive perspective. The importance of this
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