Transcript Peripheral Nervous System - UBC Psychology`s Research Labs

Psychology 304:
Brain and Behaviour
Lecture 4
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Research Methods and The Structure of the Nervous
System
1. How do biological psychologists assess the structure
and function of the nervous system? (continued)
2. What are the primary divisions of the nervous system?
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By the end of today’s class, you should be able to:
1. discuss the goals and methods of EEG, MEG, and
electrical stimulation.
2. describe lesioning techniques.
3. distinguish between the central and peripheral
nervous systems.
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How do biological psychologists assess the structure
and function of the nervous system?
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.
 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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Beta waves
(15-20 Hz)
Alpha waves
(8-12 Hz)
Delta waves
(1 Hz)
EEG Recordings Associated with
Wakefulness and Sleep
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Image 2
Image 1
EEG Recordings for
Comatose Patients
Image 3
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Magnetoencephalography (MEG): A recording
technique in which magnetic sensors (SQUIDs) are
placed on the scalp. The sensors measure the
magnetic activity of a large number of nerve cells.
Provides a measure of brain activity.
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Presentation
of visual
stimulus
MEG Recording and Plot on 3D
Image of Participant’s Head
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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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Primary
motor
cortex
The Motor Homunculus
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 A recently developed form of stimulation is repeated
trans-cranial magnetic stimulation. Magnetic pulses
are applied to the scalp, creating an electrical current
below the stimulation site.
This method reduces the symptoms associated with
depression, mania, obsessive-compulsive disorder,
and post-traumatic stress disorder.
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6. Lesion
 Allows researchers to determine the functions of
distinct brain regions (i.e., functional localization).
 Involves examining the consequences of naturallyoccurring or deliberately produced injuries to neural
tissue (i.e., lesions).
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 A number of techniques exist to create deliberate
lesions. Examples:
Aspiration lesions
Radio-frequency lesions
Cryogenic blockade
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A Lesion in Wernicke’s Area
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Example of the speech of an individual with
Wernicke’s aphasia. The individual is describing a
picture of a child taking a cookie.
“Uh, well this is the ... the … of this. This and this and
this and this. These things going in there like that. This
is … things here. This one here, these two things
here. And the other one here, back in this one, this
one look at this one.”
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What are the primary divisions of the nervous
system?
• The nervous system is comprised of two major divisions:
1. Central Nervous System (CNS)
 The CNS is located in the skull and spine.
 The CNS consists of two subdivisions: The brain and
spinal cord.
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Brain
Spinal
Cord
The CNS
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2. Peripheral Nervous System (PNS)
 The PNS is located outside of the skull and spine.
 The PNS consists of nerves that extend throughout
the body.
These nerves: (a) carry sensory information about
the external and internal environment to the CNS,
and (b) carry motor signals from the CNS to other
regions of the body.
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The PNS
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Research Methods and The Structure of the Nervous
System
1. How do biological psychologists assess the structure
and function of the nervous system? (continued)
2. What are the primary divisions of the nervous system?
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