Transcript Document

Psychology 304:
Brain and Behaviour
Lecture 28
1
The Auditory System
1. What is the structure of the ear and where are the
receptors for sound? (continued)
2. How is information about sound relayed to the brain?
3. What are the major areas of the brain that are
associated with the perception of sound?
4. What is the neurological basis of deafness?
2
By the end of today’s class, you should be able to:
1. describe the structural and functional features of the
inner ear.
2. review the pathway by which auditory information is
transmitted from receptors to the brain.
3. describe the duplex theory of sound localization.
3
4. identify the locations and functions of the primary
cortex, secondary cortex, and association areas for
the auditory system.
5. discuss the three primary causes of deafness.
4
What is the structure of the ear and where are the
receptors for sound? (continued)
• The vibrations of the cochlear fluid are ultimately
dissipated by the round window.
• When hair cells are stimulated, action potentials are
triggered that pass down axons of the auditory nerve—a
branch of cranial nerve VIII.
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The Structure of the Ear
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How is information about sound relayed to the brain?
• Sound information is relayed to the brain via a network of
auditory pathways.
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Pathways of the Auditory System
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Duplex Theory of Sound Localization
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What are the major areas of the brain that are associated
with the perception of sound?
• The majority of thalamic neurons that receive sound
information subsequently project the information to the
primary auditory cortex. Thereafter, information is
projected to the secondary auditory cortex (SII) and
association areas.
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Auditory Areas of the Brain
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• Current theory suggests two large areas of auditory
association cortex: the prefrontal cortex and the posterior
parietal cortex.
• The anterior auditory pathway leading to the prefrontal
cortex is thought to be involved in identifying sounds
(“what”); the posterior auditory pathway is thought to be
involved in locating sounds (“where”).
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Pathways to Auditory Association Cortex
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What is the neurological basis of deafness?
• Although impaired hearing is a common human disability,
complete deafness is rare.
• There are three common classes of hearing impairments:
conductive deafness (outer or middle ear damage),
sensorineural deafness (inner ear damage), and central
deafness (cortical damage).
14
The Auditory System
1. What is the structure of the ear and where are the
receptors for sound? (continued)
2. How is information about sound relayed to the brain?
3. What are the major areas of the brain that are
associated with the perception of sound?
4. What is the neurological basis of deafness?
15