Copyright © 2006 by Allyn and Bacon 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.
Copyright © 2006 by Allyn and Bacon Methods of Visualizing the Living Human Brain - Structure Contrast X-Rays – inject something that absorbs X-rays less or more than surrounding tissue Cerebral angiography X-Ray Computed Tomography (CT) 2-D images combined to create a 3-D one Magnetic Resonance Imaging (MRI) Produces 3-D images with high spatial resolution
Copyright © 2006 by Allyn and Bacon Methods of Visualizing the Living Human Brain - Functional Positron Emission Tomography (PET) Inject radioactive 2-DG Functional MRI (fMRI) Visualizing oxygen flow in the brain Magnetoencephalography (EMG) Measures changes in magnetic fields
Copyright © 2006 by Allyn and Bacon fMRI Vs PET Nothing injected. Provides both structural and functional information in one image Spatial resolution is better than with PET (Note that MEG has better temporal resolution) Can create 3-D images of activity over the entire brain
Copyright © 2006 by Allyn and Bacon Recording Human Psychophysiological Activity Recording physiological activity from the body surface Electroencephalogram (EEG) Muscle tension and eye movement Skin conductance and cardiovascular activity
Copyright © 2006 by Allyn and Bacon 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) Event-related potentials may also be of interest
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Measures of Somatic Nervous System Activity Electromyography – muscle tension Resulting electromyogram (EMG) can be used as a measure of psychological arousal Electrooculography – eye movement Electrooculogram (EOG)
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Figure 5.13
Copyright © 2006 by Allyn and Bacon Measures of Autonomic Nervous System Activity Electrodermal – appears to reflect activity of sweat glands Skin conductance level (SCL) - background Skin conductance response (SCR) – measures transient changes Cardiovascular – blood vessels and heart Heart rate Blood pressure Blood volume
Copyright © 2006 by Allyn and Bacon 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
Copyright © 2006 by Allyn and Bacon Invasive Physiological Research Methods Animal research Lesioning Electrical stimulation Invasive recording methods Manipulating or measuring within the brain
Copyright © 2006 by Allyn and Bacon 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
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Lesion Methods Remove, damage, or destroy a part of the brain to observe impact on behavior Aspiration lesions – suction - cortex Radio-frequency lesions – heat destroys tissue Knife cuts – may damage surrounding area Cryogenic blockade – “reversible lesion”
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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.
Copyright © 2006 by Allyn and Bacon 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
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Pharmacological Research Methods Routes of drug administration Selective chemical lesions Measuring chemical activity in the brain Locating neurotransmitters and receptors
Copyright © 2006 by Allyn and Bacon Routes of Drug Administration Fed to the stomach Injected - described by injection sight: stomach (intragastric) peritoneal cavity (intraperitoneal, IP) large muscle (intramuscular, IM) tissue under the skin (subcutaneous, sc) large surface vein (intravenous, IV) Cannula – used to administer drug directly to brain
Copyright © 2006 by Allyn and Bacon Thinking about routes of drug administration.. What advantage is there to using a cannula to put the drug directly into the brain? Why do the drug dependent often administer drugs IV? Have you ever had an injection SC?
Copyright © 2006 by Allyn and Bacon Selective Chemical Lesions Neural poisons (neurotoxins) selectively target specific nervous system components Kainic or ibotenic acid – destroy cell bodies 6-hydroxydopamine (6-OHDA) – destroys noradrenergic and dopaminergic neurons
Copyright © 2006 by Allyn and Bacon Measuring Chemical Activity of the Brain 2-Deoxyglucose (2-DG) technique Inject animal with radioactive 2-DG and allow it to engage in behavior of interest Use autoradiography to see where radioactivity accumulates in brain slices Cerebral dialysis – measures extracellular concentration of specific chemicals in live animals
Copyright © 2006 by Allyn and Bacon Locating Neurotransmitters and Receptors Dye or radioactive labels used to visualize the protein of interest Immunocytochemistry – based on the binding of labeled protein-specific antibodies Immune response - Antibodies created that bind and remove/destroy antigens (foreign proteins) In situ hybridization – uses labeled RNA to locate neurons with complementary mRNA
Copyright © 2006 by Allyn and Bacon Genetic Engineering Gene knockout techniques Subjects missing a given gene can provide insight into what the gene controls Difficult to interpret results – most behavior is controlled by many genes and removing one gene may alter the expression of others Gene replacement techniques Both are currently being intensely studied
Copyright © 2006 by Allyn and Bacon Cognitive neuroscience – assumptions Each complex cognitive process results from the combined activity of simple cognitive processes (constituent cognitive processes) Each complex cognitive process is mediated by neural activity in a particular area of the brain
Copyright © 2006 by Allyn and Bacon Cognitive Neuroscience Goal is to identify the parts of the brain that mediate various constituent cognitive processes Paired-image subtraction technique – compare PET or fMRI images during several different cognitive tasks
Copyright © 2006 by Allyn and Bacon Behavioral Paradigms Procedures developed for the investigation of a particular behavioral phenomenon Assessment of species-common behaviors Traditional conditioning paradigms Seminatural animal learning paradigms
Copyright © 2006 by Allyn and Bacon 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
Copyright © 2006 by Allyn and Bacon 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
Copyright © 2006 by Allyn and Bacon Seminatural Learning Paradigms Mimic situations that an animal might encounter in its natural environment Conditioned taste aversion Radial arm maze Morris water maze Conditioned defensive burying