Transcript How do biological psychologists assess the structure and function of

Psychology 304:
Brain and Behaviour
Lecture 4
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Research Methods
1. How do biological psychologists assess the structure
and function of the nervous system? (continued)
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By the end of today’s class, you should be able to:
1. describe the diverse methods used by biological
psychologists to assess nervous system structure and
function.
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How do biological psychologists assess the structure
and function of the nervous system? (continued)
3. Imaging
 Allows researchers to observe the structure and
function of the living brain.
 A number of imaging techniques are available.
Examples:
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Computerized tomography (CT): Computers are
used to enhance X-ray images of the nervous
system. Provides images of brain structure.
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CT Scans (Single Slice and 3D)
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Positron emission tomography (PET): Subjects are
administered a radioactive substance, often
attached to glucose. A scanner detects the
radioactive substance, indicating where glucose
consumption and physiological activity are
greatest. Provides images of brain activity.
Red and yellow indicate areas of high activity.
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PET Scans (Single Slice)
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Functional magnetic resonance imaging (fMRI):
Magnetic fields are used to detect changes in
oxygen flow. A scanner detects brain regions
where oxygen is delivered at higher
concentrations, indicating where physiological
activity is greatest. Provides images of brain
structure and brain activity.
Red and yellow indicate areas of high activity.
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fMRI Scans (Single Slice)
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fMRI Scan (3D)
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4. Recording
 Allows researchers to record the electrical and
magnetic output of the living brain.
 The small electrical charges and magnetic fields that
nerve cells generate are measured using
electrodes.
 A number of recording techniques are available.
Examples:
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Electroencephalography (EEG): Electrodes,
placed on the scalp, measure the electrical
activity of a large number of nerve cells. Changes
in EEG signals that are elicited by the
presentation of sensory stimuli are referred to as
sensory evoked potentials. Provides a measure
of brain activity.
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EEG Recordings Associated with
Different States of Consciousness
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Presentation of
visual stimulus
Sensory Evoked Potentials
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Image 2
Image 1
EEG Recordings for
Comatose Patients
Image 3
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Single cell recordings: Surgically implanted
microelectrodes measure the electrical activity of
single nerve cells. Provides a measure of the
activity of a single neuron. Typically conducted
with nonhuman subjects.
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Single Cell Recording
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5. Electrical Stimulation
 Allows researchers to determine the functions of
distinct brain regions (i.e., functional localization).
 Involves artificially stimulating distinct regions and
assessing changes in behaviour.
 Electrical stimulation is delivered through electrodes;
the electrical current increases the firing of neurons
at the tip of the electrode.
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 Stimulation is applied during neurosurgery.
 Using this method, researchers have identified
brain regions that produce distinct motor
movements. These regions are depicted by the
motor homunculus:
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Primary motor
cortex
The Motor Homunculus
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Research Methods
1. How do biological psychologists assess the structure
and function of the nervous system? (continued)
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