Copyright ©Mark Nelson, 2002. All rights reserved.
Chapter 12: Hearing
What you need to know

(exam questions will be a drawn from this subset of material)

Where are the receptor cells that transduce sound information? What are they called?  What form of energy do they transduce  (p. 287-289)

What is the general structural organization of the cochlea?  (p.291, Fig. 12-3)

What are the two main classes of hair cells in the mammalian cochlea? Which are responsible for sound transduction (p. 290-291)

Where are the cell bodies of the hair cells in the cochlea?  (p. 291)

Where are the tips of the stereocilia?  (p. 290-291) 

What differential motion do hair cells detect?  (p. 290-291)

Which of the two membranes is stiffer?  (p.290)

What forms the extracellular fluid around the hair cells?  What's unusual about it? (p. 290)

Where are the transduction channels located? what ion flows through the channel? (p.290)

Is the ionic current through the channels hyerpolarizing or depolarizing?  (p. 290)

Are hair cells spiking or non-spiking? (p. 290)

What mechanisms contribute to frequency tuning of cochlear hair cells?  (p. 292-296)

What does a typical threshold tuning curve look like for an auditory neuron ?  (p. 294, Fig. 12-6)

How does the auditory nerve code what frequencies are present in a complex sound?  (p.296-297)

If the frequency of APs is related to the frequency of the sound, then how is intensity coded by auditory afferents?  (p. 296-297)

What is two-tone suppression?  (p. 296-297)

What two physical cues does a barn owl use to localize the direction of a sound in space?  (p. 300-302)

What physical cue provides information about azimuthal (left-right) position of the source?  elevation (up-down)?  (p. 300-302)

What stage of processing contains a topographic map of sound direction in the barn owl?  (p. 300-302)

Why is the topographic map of auditory space in the barn owl considered to be a computational map?  (p. 300-302)

What additional properties of a sound source do bats analyze (in addition to frequency and spatial direction)?  (p. 302-304)

Where in the bat's brain would you find topographic maps of target distance and target velocity?  (p. 302-304)

Which class of  invertebrates have "true ears" that are capable of detecting high-frequency sound?  (p. 304-306)

What different types of sound receptor organs are found among insects?  (p. 304-306)

What similarities are there in the organization of vertebrate and invertebrate auditory systems?  (p.305-307)