Download Lecture 9

Chapter 5
The Research Methods
of
Biopsychology
Understanding What
Biopsychologists Do
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Methods of Visualizing the Living
Human Brain - Structure
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Contrast X-Rays – inject something that
absorbs X-rays less or more than surrounding
tissue
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Cerebral angiography
X-Ray Computed Tomography (CT)
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2-D images combined to create a 3-D one
Magnetic Resonance Imaging (MRI)
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Produces 3-D images with high spatial resolution
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Methods of Visualizing the Living
Human Brain - Functional
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Positron Emission Tomography (PET)
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Functional MRI (fMRI)
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Magnetoencephalography (EMG)
• Inject radioactive 2-DG
• Visualizing oxygen flow in the brain
• Measures changes in magnetic fields
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fMRI Vs PET
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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
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Recording Human
Psychophysiological Activity
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Recording physiological activity from the body
surface
Electroencephalogram (EEG)
Muscle tension and eye movement
Skin conductance and cardiovascular activity
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EEG – measuring “brain waves”
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A measure of the average electrical
activity of the brain.
Some EEG wave forms associated
with:
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Specific states of consciousness
Cerebral pathology (such as epilepsy)
Event-related potentials may also be
of interest
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Copyright © 2006 by Allyn and
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Copyright © 2006 by Allyn and
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Measures of Somatic Nervous
System Activity
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Electromyography – muscle tension
• Resulting electromyogram (EMG) can be
used as a measure of psychological arousal
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Electrooculography – eye movement
• Electrooculogram (EOG)
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Copyright © 2006 by Allyn and
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Figure 5.13
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Measures of Autonomic Nervous
System Activity
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Electrodermal – appears to reflect activity of
sweat glands
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Skin conductance level (SCL) - background
Skin conductance response (SCR) – measures
transient changes
Cardiovascular – blood vessels and heart
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Heart rate
Blood pressure
Blood volume
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Measures of Autonomic Nervous
System Activity - Cardiovascular
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Heart rate
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Electrocardiogram (ECG, EKG) records electrical
signals associated with heartbeats
Blood pressure
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Measured with a sphygmomanometer
Blood volume
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Plethysmography refers to techniques for measuring
changes in blood volume in a particular body part
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Invasive Physiological Research
Methods
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Animal research
Lesioning
Electrical stimulation
Invasive recording methods
Manipulating or measuring within the
brain
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Stereotaxic Surgery
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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
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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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Copyright © 2006 by Allyn and
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Electrical Stimulation
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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.
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Invasive Electrophysiological
Recording Methods
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Intracellular unit recording
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Membrane potential of a neuron
Extracellular unit recording
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Firing of a neuron
Multiple-unit recording
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Firing of many neurons
Invasive EEG recording
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Pharmacological Research Methods
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Routes of drug administration
Selective chemical lesions
Measuring chemical activity in the brain
Locating neurotransmitters and
receptors
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Routes of Drug Administration
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Fed to the stomach
Injected - described by injection sight:
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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
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Thinking about routes of drug
administration..
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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?
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Selective Chemical Lesions
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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
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Measuring Chemical Activity of the
Brain
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2-Deoxyglucose (2-DG) technique
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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
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Locating Neurotransmitters and
Receptors
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Dye or radioactive labels used to visualize the protein of
interest
Immunocytochemistry – based on the binding of labeled
protein-specific antibodies
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Immune response - Antibodies created that bind and
remove/destroy antigens (foreign proteins)
In situ hybridization – uses labeled RNA to locate neurons
with complementary mRNA
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Genetic Engineering
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Gene knockout techniques
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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
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Cognitive neuroscience –
assumptions
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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
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Cognitive Neuroscience
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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
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Behavioral Paradigms
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Procedures developed for the investigation of a
particular behavioral phenomenon
Assessment of species-common behaviors
Traditional conditioning paradigms
Seminatural animal learning paradigms
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Assessment of Species-Common
Behaviors
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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
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Traditional Conditioning Paradigms
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Pavlovian conditioning
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Pairing an unconditioned stimulus with a conditioned
stimulus
Pavlov’s dogs
Operant conditioning
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Reinforcement and punishment
Self-stimulation
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Animal works for electrical stimulation
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Seminatural Learning Paradigms
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Mimic situations that an animal might
encounter in its natural environment
Conditioned taste aversion
Radial arm maze
Morris water maze
Conditioned defensive burying
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