1. A person has unilateral hearing loss. Based only on this limited amount of information, which of the following statements best indicates a likely site of lesion?

A. Acoustic division of the eighth cranial nerve
B. Superior olivary complex
C. Lateral lemniscus
D. Primary auditory cortex

Comment: Unilateral damage to the auditory pathway after the first synapse in central nervous system does not lead to unilateral deafness because of the extensive crossing of information. The only sites where a lesion can produce deafness in one ear are the peripheral auditory structures, eighth nerve, or cochlear nuclei.

2. Preferential loss of perception of high-frequency sounds is best explained by which of the following conditions?

A. Degeneration of hair cells at the apex of the cochlear
B. Degeneration of hair cells at the base of the cochlear
C. Damage to the lateral superior olivary nucleus
D. Damage to the inferior colliculus

Comment: Whereas the lateral superior olivary nucleus is important for localizing high-frequency sounds, this does not imply that it is where high-frequency sounds are selectively processed for perception. Indeed, there is a parallel path for all frequencies through the dorsal cochlear nucleus, which does not synapse in the lateral superior olivary nucleus. By contrast, when hair cells of the base of the cochlea have degenerated all transductive machinery for high-frequency sounds is lost.

3. Which of the following contributes most of the axons in the trapezoid body?

A. Inferior colliculus
B. Superior olivary nucleus
C. Dorsal cochlear nucleus
D. Anteroventral cochlear nucleus

Comment: The superior olivary nucleus contributes a small number of axons to the trapezoid body. But by far, most axons come from the anteroventral cochlear nucleus.

4. Which is not a property of the medial superior olivary nucleus?

A. Important for processing low-frequency sounds
B. Receives an inhibitory input from the nucleus of the trapezoid body
C. Receives monosynaptic input from the ipsilateral and contralateral anteroventral nucleus
D. Projects to the inferior colliculus

Comment: Neurons of the nucleus of the trapezoid body synapse with the lateral, not medial, superior olivary nucleus. This is part of the mechanism for localizing high-frequency sounds. The medial superior olivary nucleus is part of the circuitry for localizing low-frequency sounds.

5. Which of the following statements best describes the connections/functions of the brachia of the two colliculi?

A. The brachia of the two colliculi are both afferent structures because they carry sensory information.
B. The brachia of the two colliculi are both efferent structures because they carry information from each of the colliculi to other brain structures.
C. The brachium of the inferior colliculus is an afferent structure because it transmits auditory information, and the brachium of the superior colliculus is an efferent structure because it transmits information about eye movement control.
D. The brachium of the inferior colliculus is an efferent structure because it transmits information away from the inferior colliculus, and the brachium of the superior colliculus is an afferent structure because it brings information into the superior colliculus.

Comment: Whereas afferent and efferent are often used interchangeably for sensory and motor, this is not true. Afferent means to bring information—whether sensory or motor in function—to a structure, whereas efferent means to bring information away from that structure.

6. Which of the following best completes this sentence: The inferior colliculus

A. receives convergent auditory information from all of the lower auditory brain stem nuclei.
B. receives information only from the dorsal cochlear nucleus.
C. receives information only from the anteroventral cochlear nucleus.
D. receives convergent information from the medial and lateral superior olivary nuclei.

7. The medial geniculate nucleus projects tonotopically to which of the following cortical areas?

A. Primary auditory cortex
B. Secondary auditory cortex
C. Tertiary auditory cortex
D. Auditory association cortex

8. Which of the following best describes the location of the various cortical auditory areas?

A. The areas are organized in strips from primary cortex rostrally, to higher-order areas caudally.
B. The areas are organized in strips from primary cortex caudally, to higher-order areas rostrally.
C. The areas are largely organized in a concentric scheme, with the primary area peripheral and the higher-order area central.
D. The areas are largely organized in a concentric scheme, with the primary area central and the higher-order area peripheral.

9. The auditory “what” and “where” pathways

A. are for sound identification and localization.
B. engage temporal and parietal cortical areas, respectively.
C. engage cortical areas supplied by the middle and anterior cerebral arteries, respectively.
D. are preferentially localized to the arcuate and uncinate fasciculi.

10. Diffusion tensor imaging (DTI) can be used to identify brain pathways in humans noninvasively. Using this approach, which of the following best describes the arcuate fasciculus?

A. This is a relatively straight path between the temporal and frontal lobes.
B. This is a C-shaped structure connecting the temporal and parietal lobes.
C. This is C-shaped tract linking the temporal lobe with the frontal lobe.
D. This is a relatively straight path that connects temporal with occipital lobes.