Chapter 5 The Research Methods of Biopsychology

Transcription

1 Chapter 5 The Research Methods of Biopsychology Understanding What Biopsychologists Do This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease, or lending of the program.

2 Methods of Visualizing the Living Human Brain: Structure Cerebral angiography Contrast X-rays inject something that absorbs X-rays less or more than surrounding tissue

3 X-ray computed tomography (CT): 2-D images combined to create a 3-D image

4 Magnetic resonance imaging (MRI): Produces 2-D and 3-D images with high spatial resolution 2-D image 3-D image

5 Methods of Visualizing the Living Human Brain: Function Positron emission tomography (PET) Positron emission tomography (PET) Magnetoencephalography (MEG) Brain image archives Transcranial magnetic stimulation

6 Functional MRI (fmri): BOLD fmris during visual word identification

7 Advantages of fmri over PET Nothing injected Provides both structural and functional information in one image Better spatial resolution Can create 3-D images of activity over the entire brain

8 Other Methods of Brain Visualization Magnetoencephalography (MEG): Provides higher temporal resolution of brain activity changes than fmri Brain image archives: allows researchers to share their raw data Transcranial Magnetic Stimulation (TMS): disrupts brain activity to observe effects on consciousness allows causal inference

9 Recording Human Psychophysiological Activity Recording from the body surface Electroencephalography Muscle tension Eye movement Skin conductance Cardiovascular activity

10 EEG Measuring Brain Waves A measure of the average electrical activity of the brain Some EEG wave forms associated with: Specific states of consciousness Cerebral pathology (such as epilepsy)

11 Some typical electroencephalograms and their psychological correlates

12 Measures of Somatic Nervous System Activity Electromyogram (EMG) measures muscle tension Can be used as a measure of psychological arousal

13 Measures of Somatic Nervous System Activity (continued) Electrooculogram (EOG) records eye movements

14 Measures of Autonomic Nervous System Activity: Electrodermal Appears to reflect activity of sweat glands Skin conductance level (SCL) measures background level Skin conductance response (SCR) measures transient changes

15 Measures of Autonomic Nervous System Activity: Cardiovascular Heart rate Electrocardiogram (ECG, EKG) records electrical signals associated with heartbeats Blood pressure Measured with a sphygmomanometer Blood volume Plethysmography refers to techniques for measuring changes in blood volume in a particular body part

16 Invasive Physiological Research Methods Mainly limited to animal research Lesioning Electrical stimulation Invasive recording methods Manipulating or measuring within the brain

17 Stereotaxic Surgery Used to position experimental devices within the brain Stereotaxic atlas provides coordinates for locating structures within the brain Bregma a point on the top of the skull often used as a reference point Sterotaxic instrument used to hold head steady and guide the device to be inserted

18 Stereotaxic Surgery (continued) Implanting an electrode in the rat amygdala

19 Lesion Methods Remove, damage, or destroy a part of the brain to observe impact on behavior Aspiration lesions suction cortical tissue Radio-frequency lesions heat destroys tissue Knife cuts may damage surrounding area Cryogenic blockade reversible lesion Lesion studies must be interpreted carefully because it is difficult to make small, precise lesions in the brain

20 Lesion Methods (continued) Two methods of deactivating a brain structure: a subcortical knife cut lesion and a reversible lesion by cooling to just above freezing using a cryoprobe

21 Electrical Stimulation Lesioning can be used to remove, damage, or inactivate a structure Electrical stimulation may be used to activate a structure Stimulation of a structure may have an effect opposite to that seen when the structure is lesioned

22 Invasive Electrophysiological Recording Methods Intracellular unit recording Membrane potential of a neuron Extracellular unit recording Firing of a neuron Multiple-unit recording Firing of many neurons Invasive EEG recording

23 Invasive Electrophysiological Recording Methods (continued)

24 Behavioral Research Methods of Biopsychology Neuropsychological Testing Time-consuming only conducted on a small portion of those with brain damage Assists in diagnosing neural disorders Serves as a basis for counseling/caring Provides information on effectiveness and side effects of treatment

25 Approaches to Neuropsychological Testing Single-test Used to differentiate brain damage from functional (psychological) causes Standardized-test-battery Same goal as single-test approach Halstead-Reitan, for example Customized-test-battery Now predominant Characterizes nature of psychological deficits

26 Customized-Test-Battery Approach Began to be used in the 1960s Goal is to characterize the nature of the deficits seen in the brain-damaged patient Begin with a general test and then follow with tests designed to explore the nature of the observed problems

27 Potential Components of the Initial Common Test Battery Wechsler Adult Intelligence Scale WAIS, an IQ test Often fails to detect memory deficits Token test Can detect language-related deficits Language lateralization used to identify language-dominant hemisphere Sodium amytal anesthetize one hemisphere Dichotic listening ear contralateral to dominant hemisphere shows superior hearing ability

28 Tests of Specific Neuropsychological Function Memory exploring nature of deficits Short-term, long-term, or both? Anterograde or retrograde? Semantic or episodic? Explicit or implicit? (repetition priming tests) Language problems of phonology, syntax, or semantics

29 Wisconsin Card Sorting Test (WCST) A test sensitive to frontal lobe damage Figure 5.21, p. 121

30 Behavioral Paradigms Procedures developed for the investigation of a particular behavioral phenomenon Assessment of species-common behaviors Traditional conditioning paradigms Seminatural animal learning paradigms

31 Assessment of Species- Common Behaviors Assessment of behaviors displayed by all members of a species Open-field test general activity Colony-intruder paradigm aggression and defensive behavior Elevated plus maze anxiety Tests of sexual behavior

32 Rat Sexual Behavior Measures Receptive female lordosis Lordosis quotient = lordosis/mounts Measures of male sexual behavior # mounts to intromission # intromissions to ejaculation Interval between ejaculation and next mount

33 Traditional Conditioning Paradigms Pavlovian conditioning Pairing an unconditioned stimulus with a conditioned stimulus Pavlov s dogs Operant conditioning Reinforcement and punishment Self-stimulation Animal works for electrical stimulation

34 Seminatural Learning Paradigms Mimic situations that an animal might encounter in its natural environment Conditioned taste aversion Pairing something that makes an animal ill (emetic) with a taste Challenged existing assumptions about conditioning Animals appear prepared to associate tastes and illness

35 Seminatural Learning Paradigms (continued) Radial arm maze tests spatial abilities

36 Seminatural Learning Paradigms (continued) Morris water maze tests spatial abilities Rat must find hidden platform in an opaque pool Conditioned defensive burying Following a single aversive stimulus delivered from an object, rats will spray bedding at the object Antianxiety drugs decrease the amount of burying behavior