Ascending Auditory

Question 1

primary auditory cortex (A1) (Broadmann’s area 41)

Answer 1

tonotopic map with neurons responding to lower frequencies located anteriorly and neurons responding to higher frequencies more posterior.

located deep in the lateral sulcus and is surrounded by the secondary auditory cortex

Question 2

secondary auditory cortex (AII) (Broadmann’s area 42).

Answer 2

These secondary areas surrounding AI includes Wernike’s Area, an important cortical area for understanding and processing spoken language.

Question 3

How do we determine where a sound is

Answer 3

3 main acoustical cues for sound source localization

Interaural time delays (ITDs)

Interaural level differences (ILDs)

Monaural spectral shape

There are three parallel pathways through the brainstem that appear to encode separately the ITD, ILD, and spectral cues.

Question 4

result because the ears are physically separated in space by the head. Therefore, the direction-dependent differences in path lengths that sound must travel to reach each ear from the source will generate different times of arrival of the sound at the two ears

Answer 4

Interaural time delays (ITDs)

There are three parallel pathways through the brainstem that appear to encode separately the ITD, ILD, and spectral cues.

Question 5

2 ears are separated the head, results in the cue to sound location.

Sound arriving at the ear farthest from the source is effectively attenuated relative to that arriving at the near ear thereby creating direction-dependent differences in the amplitudes, or levels, of the sounds that reach the two ears.

Answer 5

Interaural level differences (ILDs)

There are three parallel pathways through the brainstem that appear to encode separately the ITD, ILD, and spectral cues.

Question 6

change systematically with source elevation. Arise from direction- and frequency-dependent reflection and diffraction of the pressure waveforms of sounds by the pinna that result in broadband spectral patterns, or shapes, that change with location.

Answer 6

Monaural spectral shape

Spectral cue

There are three parallel pathways through the brainstem that appear to encode separately the ITD, ILD, and spectral cues.

Question 7

Central auditory pathway

Answer 7

Lateral Lemniscus–> inferior colliculus–> medial geniculate nucleus of thalamus–> auditory cortex

Question 8

receives both direct projections from the cochlear nuclei and multisynaptic input from the pontine nuclei (the nuclei of the superior olivary complex), is an obligatory relay and integration center for ascending auditory information.

Answer 8

The inferior colliculus

Question 9

From the inferior colliculus fibers project mainly to the ipsilateral _______

Answer 9

medial geniculate

Question 10

______ tract of axons (brainstem) that carries information about sound from the cochlear nucleus. Three distinct, primarily inhibitory, cellular groups are located interspersed within these fibers

Answer 10

The lateral lemniscus

Question 11

ventral cochlear nucleus (VCN), and the other the dorsal cochlear nucleus (DCN) are found on the dorsal and lateral aspects of the______

Answer 11

inferior cerebellar peduncle.

Question 12

Some axons from cells in the cochlear nucleus cross the midline to the opposite side of the brain in the dorsal acoustic stria (from DCN) and trapezoid body (from VCN). These tracts regroup as the _______ and ascend to the inferior colliculus of the midbrain.

Answer 12

lateral lemniscus

Question 13

medial geniculate nucleus

Answer 13

part of the auditory thalamus and represents the thalamic relay between the inferior colliculus (IC) and the auditory cortex (AC).