PART ONE: METHODS OF STUDYING THE NERVOUS SYSTEM

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1 PSYC*2410 Behavioural Neuroscience Chapter 5 Summary The Research Methods of Biopsychology - Two major parts of this chapter: one deals with methods of studying the nervous systems and the other deals with methods of studying behaviour - Keep in mind that most of the methods that area used to study the human brain are used for clinical purpose, for either diagnoses or treatment The Ironic Case of Professor P. - Behavioural neuroscientist who went into the hospital for tests before his brain surgery - Had a brain tumor on his right auditory-vestibular cranial nerve that had to be excised (cut off) - Auditory abilities assessed by measuring ability to detect sounds then by measuring magnitude of the EEG signals evoked in his auditory cortex by clicks in his right ear - Vestibular function (balance) tested by injecting cold water into ear - He did not feel any different until the water was so cold that most people would have been on their knees, puking - Meant hearing in right ear was poor and right vestibular nerve was barely functioning - One last test to establish baseline for surgery because if something wrong was cut the right side of his face would sag - Nurse gives needle - Professor did not regain consciousness for several days and when he did he was incapable of talking, eating or even breathing This case demonstrates that many of the research methods of biopsychology are also used in clinical settings PART ONE: METHODS OF STUDYING THE NERVOUS SYSTEM Methods of Visualizing and Simulation the Living Human Brain - Prior to the early 1970 s biopsychology was impeded by the inability to obtain images of the organ of primary interest: the living human brain - Conventional X-ray photography is useless for this purpose because it is only able to distinguish between structure that differ substantially from their surrounds (ex. a gun in a suitcase filled with clothes or a bone in flesh) - The many overlapping structures of the brain only differ slightly in their ability to absorb the radiation and therefore the X-ray would carry very little information about the shape of the individual structure it has passed through Contrast X-Rays - Useful for visualizing the brain

2 - Contrast x-ray techniques involve injecting into one compartment of the body a substance that absorbs x-rays either less than or more than the surrounding tissue; the injected substance then heightens the contrast between the compartment and the surrounding tissue during x-ray photography - Cerebral angiography a contrast x-ray technique for visualizing the cerebral circulatory system by infusing a radio-translucent dye into a cerebral artery o Most useful for localizing vascular damage, but the displacement of blood vessels from their normal position can also indicate the location of a tumor X-Ray Computed Technology - Computed tomography (CT) a computer assisted x-ray procedure that can be used to visualize the brain and other internal structures of the living body o Revolutionized the study of the human brain in the early 1970 s - During cerebral computer tomography o The patient lies with their head in the center of a large cylinder o X-ray tube on one side that projects an x-ray beam through the head to the x-ray detector on the other side o Both automatically rotate around the head, taking several x-ray photographs that are combined by a computer to generate a horizontal section of the brain o Then they are moved down to another level of the patient s brain and the process is repeated 8 or 9 times o All 8-9 scanned horizontal brain sections are combined to provide a 3D representation of the brain - Success of CT lead to the development of other techniques (ex. MRI) Magnetic Resonance Imaging - Magnet Resonance Imagining (MRI) a procedure in which high-resolution images are constructed from the measurement of waves that hydrogen atoms emit when they are active by radio-frequency waves in a magnetic field o Clearer brain images than CT o High spatial resolution the ability to detect difference in spatial location o Produces 2D and 3D images Positron Emission Tomography - Positron Emission Tomography (PET) a brain-imaging technique that has been widely used in biopsychology research because it provides images of brain activity rather than brain structure; usually by measuring the accumulation of radioactive 2-deoxyglucose (2-DG) or radioactive water in the various areas of the brain - One common version of PET: o 2-DG injected into patient s carotid artery (artery in the neck that feeds the ipsilateral cerebral hemisphere)

3 2-DG is similar to glucose so will be rapidly taken up by active cells, but does not metabolize so will accumulate in active cells until it is slowly broken down o PET scan is an image of radioactivity (indicated by colour coding) in various parts of one horizontal level of the brain If PET scan taken of patient who engages in reading for 30 seconds after 2-DG injection than the areas of the brain that were most active will be shown on the scan - Usually different levels of the brain are scanned so that the extent of brain activity can be better assessed Functional MRI - Functional MRI (fmri) produce images of the increase in oxygen flow in the blood to active areas of the brain - Possible because of two attributes of oxygenated blood: o 1. Active areas of the brain take up more oxygenated blood than need for their energy requirements and therefore oxygenated blood accumulates in active areas o 2. Oxygenated blood has magnetic properties (because oxygen influences the effect of magnetic fields on iron in the blood) BOLD signal a blood-oxygen-level-dependent (BOLD) signal, which is recorded by fmri and is related to the level of neural firing - Four advantages over PET: o Nothing has to be injected into subject o Provides both functional and structure information in the same image o Higher spatial resolution o Used to produce 3D images of activity of the entire brain Magnetoencephalography - Magnetoencephalography (MEG) a technique for recording changes produced in magnetic fields on the surface of the scalp by changes in underlying patterns of neural activity o Used to monitor brain activity o Major advantage: high temporal resolution ability of a recording technique to detect differences in time (ie. to pinpoint when an event occurred) It can record fast changes in neural activity Brain-Image Archives - Brain-Image Archive contains the raw data collected in a particular study o Other research use archives in access the raw data and compare those data to, or combine them with, their own o Published studies only contain a few summary images in each research paper which makes it virtually impossible for researchers to compare the results to their own findings which is why brain-image archives are beneficial

4 Transcranial Magnetic Stimulation - PET, fmri and MEG can all create images of brain activity but they can only show correlation, not causation - Transcranial Magnetic Stimulation provides casual relations between cortical activity and psychological phenomena - Transcranial Magnetic Stimulation (TMS) technique for disrupting the activity in an area of the cortex by creating a magnetic field under a coil positioned next to the skull; the effect of the disruption on cognition is assessed to clarify the function of the affected area of cortex o Magnetic stimulation temporarily turns off part of the brain while effects assessed o Employed to circumvent (get around) the difficultly that brain-imaging studies have in determine causation Recording Human Psychological Activity - This section deals with psychological recording methods methods of recording physiological activity from the surface of the human body - Five Described: o 1 measure of brain activity scalp EEG o 2 measures of somatic nervous system activity muscle tension and eye movement o 2 measures of autonomic nervous system skin conductance and cardiovascular activity Scalp Electroencephalography (EEG) - Measure of gross electrical brain activity - Recorded through large electrodes by a device called an electroencephalograph (EEG machine) and the technique is called electroencephalography a technique for recording the gross electrical activity of the brain through disk-shaped electrodes (about half the size of a dime), which in humans are usually taped to the surface of the scalp - Scalp EEG reflects the sum of electrical events through the head including action potentials, postsynaptic potentials and electrical signals from the skin, muscles, blood and eyes - Some EEG waves are associated with particular states of consciousness (ex. aroused, relaxed, asleep, deep sleep see Fig. 5.8 on pg. 107) o For example: Alpha waves regular 8-12-per-second, high amplitude waves that are associated with relaxed wakefulness or just before falling asleep - EEG signals decrease in amplitude as they spread from their source so a comparison of signals can indicate the origin of particular waves o This is why EEG activity is often recorded from many sites simultaneously - Psychologist more interested in event related potentials (ERPs) than the background EEG signal o ERPs the EEG waves that regularly accompany certain psychological events One commonly studied type of event related potential is the sensory evoked potential the change in the cortical EEG signal that is elicited by the momentary presentation of a sensory stimulus

5 Can be difficult to detect because noise often masks the sensory potential (ex. like detecting a whisper at a rock concert) o Signal part of any recording that is of interest o Noise part that s not o Signal averaging a method used to reduce the noise of the background Take persons response to a stimulus (ex. a click) at the exact time the stimulus starts - say 1000 times - then averages the millivolt value of the responses Then takes the response to a stimulus 1 millisecond (msec) from its start, 1000 times and averages these values Repeats for 2msec, 3msec, 4msec, etc. and averages the responses for each When these averages are plotted, the average response evoked by the click is more apparent because random background EEG is canceled out by the averaging o The analysis of average evoked potentials (AEPs) focuses on the various waves in the averaged signal Each wave characterized by its direction, positive or negative and its latency o May also see small waves in the first few seconds after the stimulus that are not influenced by the meaning of the stimulus for the subject; these are called far-field potentials EEG signals recorded in attenuated form at the scalp because they originate far away for example, in the brain stem - Initially EEG scored high on temporal resolution but failed at spatial resolution - Newer techniques can accurately locate the source of signals which allows them to be colourcoded and plotted on the surface of a 3D MRI scan Muscle Tension - Muscles fibres contract in an all-or-none fashion - When you are relaxed, a few fibres in each resting muscle are contracting to keep the muscle tension - Tense or anxious people high resting levels of muscle tension - Interested in this measure because it is an indication of psychological arousal - Electromyography the usual procedure for measuring muscles tension by recording the gross electrical discharges of muscles o Two electrodes taped to the surface of skin over the muscle of interest - Electromyogram (EMG) resulting record of raw data o Usually raw data from this converted into a more workable form and the integrated signed (ex. the total EMG activity per unit of time) is plotted which results in a smooth curve on a graph (see. Pg. 109 for a diagram) Eye Movement - Electrooculography technique for recording eye movement - Electrooculogram (EOG) resulting record - Horizontal movements measured with two electrodes placed on either side of eye

6 - Vertical one electrode above and one below the eye - The is a steady potential different between the front (positive) and back (negative) of the eyeball which allows the change in potentials to be recorded in this technique Skin Conductance - Emotional thoughts and experiences associated with increase in the skin s ability to conduct electricity - Skin conductance level (SCL) the steady level of skin conductance associated with a particular situation - Skin conductance response (SCR) the transient change in skin conductance associated with a brief experience - Thought that sweat glands are a big part of this as they tend to become active in emotional situation especially those in the hands, feet, armpits and forehead Cardiovascular Activity - Two parts: blood vessel and heart - Relationship between cardiovascular activity and emotions o Ex. white with fear, blushing bride Heart Rate - Electrocardiogram (ECG) recording of electrical signal that is associated with each heart beat through electrodes places the chest - Average resting heart rate of healthy adult 70 beats/minute Blood Pressure - Two measures: o Systoles peak pressure during heart contractions o Diastoles minimum pressure during periods of relaxation Expressed as systoles/diastoles in millimetres of mercury (mmhg) - Average resting blood pressure of an adult 130/70 mmhg - Hypertension 140/90 mmhg serious health hazard - Sphygmomanometer cuff that measures blood pressure Blood Pressure - Plethysmography various techniques for measuring changes in the volume of blood in a particular part of the body o Ex. genitals during sex - Two possible methods: o Wrap gauge around target organ Works for fingers or similarly shaped organs o Shine light through target tissue More blood there is = more light absorbed

7 Invasive Physiological Research Methods - More direct techniques - Often used on laboratory animals - 3 categories: lesion methods, electrical stimulation, invasive recording methods - But first: Stereotaxic Surgery - Means by which experimental devices are precisely positioned in the depths of the brain - Two things required: o Stereotaxic atlas a series of maps representing the 3D structure of the brain that is used to determine coordinates for stereotaxic surgery Bregma the point on the top of the skull where two of the major sutures (seams of the skull) intersect often used as a reference point in rat atlases o Stereotaxic instrument a device for performing stereotaxic surgery, composed of two parts: a head holder and an electrode holder (holds device to be inserted) Electrode holder can be moved for precision in 3 dimensions: Posterior-anterior Dorsal-ventral Lateral-medial Lesion Methods - A part of the brain is removed, damaged or destroyed - Behaviour assessed to determine function of lesioned structure - Four types: o Aspiration Lesions tissue is drawn off by suction through the fine tip of a glass pipette Used when lesions needs to be made in area of the cortical tissue that is accessible to the eyes and instrument of the surgeon o Radio-Frequency Lesions lesions made by from the heat of a radio(high)-frequency current through the target tissue from the top of a stereotaxically positioned electrode Lesion s size and shape determined by current s intensity and duration o Knife Cuts sectioning (cutting) is used to eliminate conduction in a nerve or tract o Cryogenic Blockade (aka. reversible lesions) the temporary elimination of neural activity in an area of the brain by cooling the area with a cryoprobe until neurons stop firing No structural damage Can also be produced with microinjections into the brain of local anesthetics such as lidocaine

8 - Interpreting Lesion Effects o Cannot completely destroy a structure without producing significant damage to adjacent structures o Therefore, be cautious when interpreting lesions or you may incorrectly: Attribute all the behaviours to the lesioned structure Assume the lesioned structure is only responsible for the behaviours observed (even if you didn t destroy it all) - Bilateral and unilateral Lesions o General principle, with exceptions: The behavioural effects of unilateral lesions (restricted to one have of the brain) are much milder than bilateral lesions (involving both sides of the brain) o Most experimental studies of lesion effects bilateral Electrical Stimulation - Delivered across the two tips of a bipolar electrode two insulated wires wound tightly together and cut at the end - Weak pulses of current produced an immediate increase in the firing of neurons near the tip of the electrode - Particular behaviour response depends on: electrode location, parameters of the current and the test environment in which the stimulation is administered Invasive Electrophysiological Recording Methods - Four methods: o Intracellular Unit Recording provides a moment-to-moment record of the graded fluctuations in one neuron s membrane potential Performed on chemically immobilized animals o Extracellular Unit Recording provides a record of the firing of a neuron from the extracellular fluid next to it but no information about the neuron s membrane potential Originally done on one neuron, but now up to 100 simultaneously in the same general area o Multiple Unit Recording graph of the total number of recorded action potentials per unit of time Larger tip that picks up signal from many neurons and slight change in position due to movement of the subject has little overall effect o Invasive EEG Recording EEG signals recorded though large implanted electrodes rather than through scalp electrodes Cortical EEG recorded through stainless steel skull screws Subcortical EEG recorded through stereotaxically implanted wire electrodes

9 Pharmacological Research Methods - Manipulate and record the brain using chemical methods - Drugs that increase or decrease the effects of a particular neurotransmitter and observe the behavioural consequences Routes of Drug Administration - Orally fed - Intragastrically injected though tube into the stomach - Intraperitoneally (IP) injected hypodermically into the peritoneal cavity of the abdomen - Intramuscularly (IM) into a large muscle - Subcutaneously (SC) into the fatty tissue beneath the skin - Intravenously (IV) into a large surface vein ** Problem with all these peripheral routes: many drugs do not readily pass through the Blood Brain Barrier (BBB) **Solution: - Cannula drugs administered through a fine, hollow tube that has been stereotaxically implanted into the brain Selective Chemical Lesions - More selective lesions created by inserting neurotoxins (neural poisons) that have an affinity for certain component of the nervous system o Ex. kainic acid or ibotenic acid taken up by cell bodies at the tip of the cannula o Ex. 6-hydroxy-dopamine (6-OHDA) taken up by neurons that release neurotransmitter norepinephrine or dopamine Measuring Chemical Activity of the Brain - The 2-Deoxyglucose (2-DG) Technique o Animal given radioactive 2DG (similar to glucose see PET section above) o Engages in behaviour of interest o Killed brain removed and sliced o Slices subjected to autoradiography the technique of photographically developing brain slices that have been exposed to radioactively labelled substance such as 2DG so that regions of high uptake are visible (show up as black spots) - Cerebral Dialysis o Cerebral Dialysis a method of measuring the extracellular concentration of specific neurochemicals in behaving animals with a fine tube with a short semi-permeable section is implanted in the brain, and extracellular neurochemicals are continuously drawn off for analysis Locating Neurotransmitters and Receptors in the Brain - Two techniques each involves exposing brain slices to a labeled ligand of the molecule under investigation (the ligand of a molecule is another molecule that is binds to)

10 o o Immunochemistry a procedure for locating particular proteins in the brain by labeling their antibodies with a dye or radioactive element and then exposing slices of the brain tissue to the labeled antibodies Regions of dye or radioactivity accumulation in the brain slices mark the locations of the target neuroprotein Enzymes and proteins and only neurons that release a particular neurotransmitter contain all the enzymes for synthesis, this method can be used to locate neurotransmitters In Situ Hybridization a technique for locating particular proteins in the brain; molecules that bind to the mrna that directs the synthesis of the target protein are synthesized and labeled with dye or radioactive element, and brain slices are exposed to them, they bind to the complementary strands marking the location of the neurons that release the target neuroprotein Genetic Engineering Gene Knockout Techniques Procedures for creating organisms that lack a particular gene - Knockout mice: mice that are the products of gene knockout techniques - Behavioural studies of knockout mice more difficult to interpret that first anticipated for 3 reasons: o Most behaviour traits are influenced by the activities of many interacting genes o Elimination of a gene often influences the expression of other genes o The expression of genes can be influenced by experience - Potential way to avoid some of these problems: o Antisense drugs: molecules with a sequence of nucleic acids complementary to that of the mrna associate with a target organ can deactivate the mrna and block the expression of a gene o However, turning this concept into practice is difficult because: The drug must be resistant to breakdown by the body, non-toxic and specific to the mrna being targeted Techniques must be available to deliver the drug to particular neural systems Gene Replacement Techniques Procedures for creating organisms in which a particular gene has been replaces with another - Transgenic mice: mice that contain the genetic material of another species - Can replace a gene with one from another species or; - Replace a gene with one that is identical except for the addition of a few bases that can act as a switch, turning a gene off or on in response to particular chemicals

11 PART TWO: BEHAVIOURAL RESEARCH METHODS OF BIOPSYCHOLOGY - Behavioural Paradigm a single set of procedures developed for the investigation of a particular behaviour phenomenon Neuropsychological Testing - Extremely time consuming so only prescribed for a small portion of brain-damaged patients - Can help patients in 3 important ways o By assisting in the diagnosis of neural disorders o By serving as a basis for counseling and caring for the patients o By providing a basis for objectively evaluating the effectiveness of the treatment and seriousness of side effects Modern Approaches to Neuropsychological Testing - Changed rapidly since the 1950 s - Evolved through 3 distinct phases: o Single-test approach (Before the 1950 s) Developed to distinguish between structural and functional brain damage Unsuccessful because no single test can detect all the varied and complex psychological symptoms that could potentially occur in a brain-damaged patient o Standardized-Test-Battery Approach (1960 s) Objective: identify patients with brain damage Set of tests rather than single test Halstead-Reitan Neuropsychological Test Battery o Set of tests performed poorly by brain-damaged patients in comparison to healthy patients Scores of all tests added and if they are below the cut-off line that indicates brain-damage Detects between neuropsychological patients and healthy patients, but not between neurological and psychiatric patients Customized-Test-Battery Approach Started in 1960 s and when proven successful used more frequently Objective: characterize the nature of the psychological deficits of each braindamaged patient First, series of general tests given to determine nature of the symptoms (ex. memory problem) Then, series of customized tests selected to characterize in more detail the symptoms revealed by the common battery test (ex. reveal the nature of the memory problem) Differ in 3 aspects from the previous tests:

12 Designed to measure aspects of psychological function that have been spotlighted by modern theories and data (ex. short-term and long-term memory are different) Interpretation of tests doesn t rely primarily on the patient s score because often brain damage changes the strategies used to perform a test but not the overall score Requires a more skillful examination to select the right tests to give to patients Tests of the Common Neuropsychological Test Battery - Outlines the tests commonly used in the customized battery tests - First are the general tests that would be performed - Second there is a section of the customized tests that would be selected for particular patients Intelligence - Wechsler Adult Intelligence Scale (WAIS) o Often first test, because knowing a patient s IQ can help interpret results from subsequent tests o Current version WAIS-III includes 14 subtests o Tests may help draw inferences about patient s dysfunction Low verbal ability scores left hemisphere Low performance scores right hemisphere Memory - WAIS often fails to detect memory deficits despite the two memory tests because they are the two forms of memory least likely to be disrupted by brain damage o General knowledge memory ex. Who is Queen Elizabeth? o Digit span the longest sequence of random digits that can be repeated correctly 50% of the time most people have a digit span of 7 - However, memory problems rarely escape notice because they are noticed through discussions with the patients or reported by family members Language - Patient who has not taken the WAIS test can be quickly screened for language-related deficits with a token test a preliminary test for language-related deficits that involved following verbal instructions to touch or move tokens of difference shapes, sizes and colours Language Lateralization - Usually one hemisphere is more involved with language than the other (most often the left, but in some people the right) - Test used to determine which hemisphere is dominant for language

13 - Important for interpreting results and also plan the surgery (to avoid the language areas if possible) - Two widely used tests of language lateralization o Sodium amytal test a test involving the anesthetization of first one cerebral hemisphere and then the other to determine which hemisphere plays the dominant role in language Dominant hemisphere mute for about 2 minutes Non-dominant minor speech errors o Dichotic listening test a test of language lateralization in which two different sequences of three spoken digits are presented simultaneously, one to each ear, and the subject is asked to report all of the digits heard Subjects correctly report more digits of the digits heard by the contralateral (opposite-side) to their dominant hemisphere for language Tests of Specific Neurological Function - This sections describes a few of the thousands of tests that would be used to clarify the nature of the general problems exposed by the common battery Memory - Following the discovery of a memory impairment - four fundamental questions must be answered. o Does the memory impairment involve: Short-term memory; or Long-term memory; or Both? o Are any deficits in long-term memory: Anterograde affecting the retention of things learned after the damage; or Retrograde affecting the retention of things learned before the damage; or Both? o Do long-term deficits involve: Semantic memory memory for knowledge of the world; or Episodic memory memory for personal experiences? o Are any deficits in long-term memory deficits of: Explicit memory memories of which the patient is aware and can thus express verbally; or Implicit memory memories that are demonstrated by the improved performance of the patient with the patient being conscious or them; or Both? - Many patients display severe deficits in explicit memory but none in implicit memory; repetition priming tests are used to test this

14 - Repetition priming tests test of implicit memory; in one example, a list of words is presented for patients to study but not remember, then fragments of the original words are presented and the subject is asked to complete them o Ex. p u _ p which is fragments of the original word on the list purple o Amnesic patients can often complete the words as well as healthy subjects o However, they have no conscious memory of any of the words on the original list or even reading the list Therefore, they display good implicit memory of experiences without explicit memory of them Language - If a patient has speech problems it could be one of 3, problems with: o Phonology the rules governing the sounds of language o Syntax the grammar of the language o Semantics the meanings of the language - Reading problems can also vary ex. dyslexic patients o Some can remember the rules of pronunciation but have difficultly pronouncing words that do not follow the rules ex. come and tongue o Some can pronounce simple familiar words based on memory but have lost the ability to apply the rules ex. they cannot pronounce non-words such as trapple or fleeming Frontal Lobe Function - Injuries to the frontal lobes are common - Wisconsin Card Sorting Test a neuropsychological test that evaluates a patient s ability to remember that previously learned rules of behaviour are no longer effective and to learn to respond to new rules o Performance on this test is sensitive to frontal lobe damage o Deck of cards with different shapes, colours and number of symbols on each o The patient is not told how to sort the cards o As they begin to sort they are told whether each card is placed correctly or incorrectly o As soon as they discover the sorting pattern (ex. by colour) it is switch to another one (ex. by shapes) and the cards being sorted by colour are said to be incorrect o A patient with frontal lobe damage will continue to sort by the original rule for 100 incorrect trials or more - They have a problem called perseveration difficulty learning and remembering that previously appropriate guidelines for effective behaviour are no longer appropriate Behavioural Methods of Cognitive Neuroscience - Cognitive neuroscience a division of biopsychology that focuses on the use of functional brain imaging to study the neural bases of human cognition o Predicated based on two related assumptions

15 Each complex cognitive process results from the combined activity of simple cognitive processes called constituent cognitive processes Each constituent cognitive process is mediated by neural activity in a particular area of the brain o One of the main goals is to identify parts of the brain that mediate various constituent cognitive processes - One key behavioural research method in such research is the paired-image subtraction technique the use of PET or fmri to locate constituent cognitive processes in the brain by producing an image of the difference in brain activity associated with two cognitive tasks that differ in terms of a single constituent cognitive process o Ex. interested in the part of the brain that causes subjects to make a word association o Difficulty with measuring this is there are many other parts of the brain involved: seeing the word, reading the words and speaking o Solution: take a PET or fmri of two difference activities that only different by one constituent cognitive process Ex. One of the subjects reading nouns from a computer screen and the second of the subjects saying an associated word with the one on the computer screen (ex. truck drive) Then subtract the activity images that they recorded during the two tasks to obtain a difference image which illustrates the areas of the brain that are specifically involved in the constituent cognitive process of forming the word association One problem with this is the noise that will also be recording (ex. thinking about being hungry, seeing a fly on the screening, wondering how much longer the test will last) This can be overcome with signal averaging discussed earlier o Often averages of many subjects are combined to create a mean difference image o However, the problem: if two subjects had specific but different patterns of cortical activity, the averaged image would reveal little about either Serious problem because cortical localization of cognitive abilities in people vary substantially; and The area of the cortex that controls a particular ability can change in an individual as a result of experience o r damage Biopsychological Paradigms of Animal Behaviour - Paradigms for Assessment of Species-Common Behaviours o Used to study species-common behaviours behaviours that are displayed in the same manner by virtually all like members of a species or at least by those of the same age and sex (ex. swimming, eating, drinking, copulation, fighting, etc.)

16 Open Field Test a method for recording and scoring the general activity of an animal in a large, barren chamber Sometimes measures number of lines crossed or number of boluses (pieces of excrement) Fearfulness low activity and high number of boluses Fearful rats highly thimotaxic rarely venture away from the walls of the test chamber and rarely engage in such activities as rearing and grooming Rats often fearful when placed in new environment but this declines with exposure Tests of Aggressive and Defensive Behaviour Colony Intruder Paradigm a paradigm for the study of aggressive and defensive behaviours in male rats; a small male intruder rate is placed in an established colony in order to study the aggressive responses of the colony s alpha male and the defensive responses of the intruder o Sometimes score defensiveness by looking at the response to the experimenter when he tries to pick the rat up Lowest no reaction Highest biting Elevated Plus Maze an apparatus for recording defensiveness or anxiety in rats by assessing their tendency to avoid the two open arms of a plus-sign-shaped maze mounted some distance about the floor or a lab o Commonly used to study anxiolytic (anxiety-reducing) drugs Increase time spent on open arms Tests of Sexual Behaviour Measures of male rat sexual behaviour o # of mounts required for intromission o # of intromissions required for ejaculation o Interval between ejaculation and the re-initiation of mounting Measure of female rat sexual behaviour o Lordosis quotient proportion of mounts that elicit lordosis Lordosis the arched-back, rump-up, tail-to-the-side posture of a female rodent indicating she is receptive to sexual activity, which serves to facilitate intromission - Traditional Conditioning Paradigms o Pavlovian conditioning paradigm a paradigm in which the experimenter pairs an initially neutral stimulus (conditional stimulus) with a stimulus (unconditioned stimulus) that elicits a reflexive response (unconditional response); after several pairings, the neutral stimulus elicits a response (conditional response)

17 o Operant conditioning paradigm a paradigm in which the rate of a particular voluntary response is increased by reinforcement or decreased by punishment o Self-stimulation paradigm a paradigm in which animals press a lever to administer reinforcing electrical stimulation to their own brains - Seminatural Animal Learning Paradigms o Conditioned Taste Aversion avoidance response that develops to tastes of food whose consumption has been followed by illness. Receive Emetic nausea-inducing drug after consuming an unfamiliar food Single conditioning learn to avoid food after only one trial Increases their chances of survival Rats as neophobic afraid of new things, so only try new things in small quantities Challenged three views o o o That animal conditioning requires a step-by-step process Temporal continguity rats acquire an aversion even when they become ill several hours after eating Principle of equipotentionality the view that conditioning proceeds in basically the same manner regardless of the particular stimuli o Rats readily learn associations between taste and illness but more difficult to learn associations with food colour and nausea Radial Arm Maze 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. Tests spatial abilities Depends on ability to navigate quickly and accurately though environment based on external cues because the arms are all identical and figure out which ones are most likely to contain food and water Morris Water Maze designed to study spatial abilities of rat; rats are put in a milky cool water until they discover an escape platform Use external cues to navigate to platform Extremely useful for assessing the navigational skills of lesioned or drugged animals Conditioned Defensive Burying rats receive a single aversive stimulus (ex. shock, air blast, noxious odor) from an object mounted on the wall of the chamber just above the floor which is littered with bedding material; rats learn after a single trial that the bedding is a threat Used to study neurochemistry of anxiety