The Ear

Middle ear amplification

20x pressure increase of soundwave

Scala media

Space in the cochlea between the basilar membrane and reissner’s membrane

Scala vestibuli

Space in the cochlea above basilar membrane, connected to the round window

Scala tympani

Space in the cochlea below the reissner’s membrane, connected to the oval window

Basilar membrane

Membrane responsible for frequency discrimination

Tectorial membrane

Cochlear apex

The end of the cochlea with a thin basilar membrane

Cochlear base

The front of the cochlea with a thick basilar membrane

Inner hair cells

Row of cells that allow K⁺ ions to enter the cell when cilia bend towards the tallest cilia, largely connected to afferent neurons

Outer hair cells

Rows of cells that enhance the motion of the basilar membrane, largely connected to efferent neurons

Low frequencies

Frequencies that resonate with the thinner parts of the basilar membrane

High frequencies

Frequencies that resonate with thicker parts of the basilar membrane

Frequency asymmetry

Spontaneous firing

Nerve fibers firing at 0 dB

High SR nerve fibers

Nerve fibers detecting volume of stimuli at <40 dB

Low SR nerve fibers

Nerve fibers detecting volume of stimuli at >40 dB

Stimulus onset

Time of greatest firing rate

Single nerve fiber response

Firing rate related to stimulus amplitude

Pooled nerve fiber response

Firing rate related to stimulus frequency and extreme stimulus amplitude

Half-wave rectification

Superior olive

Part of the brainstem that compare information between ears

Synchronization coefficient