Sensation And Perception Ch. 9 Physiology And Psychoacoustics

Front 1

acoustic reflex

Back 1

A reflex that protects the ear from intense sounds, via contraction of the stapedius and tensor tympani muscles.

Front 2

afferent fiber

Back 2

A neuron that carries sensory information to the central nervous system. Compare efferent fiber.

Front 3

amplitude

Back 3

The magnitude of displacement (increase or decrease) of a sound pressure wave.

Front 4

audibility curve

Back 4

A map of just barely audible tones of varying frequencies.

Front 5

auditory nerve fibers

Back 5

A collection of neurons that convey information from hair cells to (afferent) and from (efferent) the brain stem. This collection also includes neurons for the vestibular system.

Front 6

basilar membrane

Back 6

A plate of fibers that forms the base of the cochlear partition and separates the middle and tympanic canals.

Front 7

belt area

Back 7

A region of cortex directly adjacent to the primary auditory cortex (A1) with inputs from A1 where neurons respond to more complex characteristics of sounds. Compare parabelt area.

Front 8

characteristic frequency (CF)

Back 8

The frequency to which a particular aud­itory nerve fiber is most sensitive.

Front 9

cochlea

Back 9

A spiral structure of the inner ear containing the organ of Corti.

Front 10

cochlear nucleus

Back 10

The first brain stem nucleus at which afferent auditory nerve fibers synapse.

Front 11

cochlear partition

Back 11

The combined basilar membrane, tectorial membrane, and organ of Corti, which are together responsible for the transduction of sound waves into neural signals.

Front 12

complex tone

Back 12

A sound wave consisting of more than one sinusoidal component of different frequencies. Compare sine wave.

Front 13

conductive hearing loss

Back 13

Hearing loss caused by problems with the bones of the middle ear.

Front 14

critical bandwidth

Back 14

The range of frequencies that are conveyed within a channel in the auditory system.

Front 15

decibel (dB)

Back 15

A unit of measure for the physical intensity of sound. Decibels define the difference between two sounds as the ratio between two sound pressures. Each 10:1 sound pressure ratio equals 20 dB, and a 100:1 ratio equals 40 dB.

Front 16

ear canal

Back 16

The canal that conducts sound vibrations from the pinna to the tympanic membrane and prevents damage to the tympanic membrane.

Front 17

efferent fiber

Back 17

A neuron that carries information from the central nervous system to the periphery. Compare afferent fiber.

Front 18

equal-loudness curve

Back 18

A map plotting sound pressure level (dB SPL) against the frequency for which a listener perceives constant loudness.

Front 19

Fourier analysis

Back 19

A mathematical theorem by which any sound can be divided into a set of sine waves. Combining these sine waves will reproduce the original sound.

Front 20

frequency

Back 20

For sound, the number of times per second that a pattern of pressure change repeats.

Front 21

fundamental frequency

Back 21

The lowest-frequency component of a complex periodic sound.

Front 22

hair cells

Back 22

Cells that support the stereocilia that transduce mechanical movement into neural activity sent to the brain stem; hair cells also receive inputs from the brain.

Front 23

harmonic spectrum

Back 23

The spectrum of a complex sound in which energy is at integer multiples of the fundamental frequency.

Front 24

helicotrema

Back 24

The connection between the tympanic and vestibular canals at the apex of the cochlea.

Front 25

hertz (Hz)

Back 25

A unit of measure for frequency, where 1 Hz equals one cycle per second.

Front 26

high-spontaneous fibers

Back 26

Auditory nerve fibers with high rates (>30 per second) of spontaneous firing; high-spontaneous fibers increase their firing rate in response to relatively low levels of sound. Compare low-spontaneous fibers and mid-spontaneous fibers

Front 27

incus

Back 27

The middle ossicle; the connection between malleus and stapes.

Front 28

inferior colliculus

Back 28

A midbrain nucleus in the auditory pathway.

Front 29

inner ear

Back 29

A hollow cavity in the temporal bone of the skull and the structures within this cavity: the cochlea and vestibular canals.

Front 30

intensity

Back 30

The amount of sound energy falling on a unit area (such as cm2).

Front 31

isointensity curve

Back 31

A map plotting the firing rate of an auditory nerve fiber against varying frequencies at varying intensities.

Front 32

loudness

Back 32

The psychological aspect of sound related to perceived intensity or magnitude.

Front 33

low-spontaneous fibers

Back 33

Auditory nerve fibers with low rates (<10 per second) of spontaneous firing; low-spontaneous fibers require relatively intense sound before firing at higher rates. Compare high-spontaneous fibers and mid-spontaneous fibers.

Front 34

malleus

Back 34

The first ossicle; the malleus receives vibration from the tympanic membrane and is attached to the incus.

Front 35

masking

Back 35

Using a second sound, frequently noise, to make the detection of another sound more difficult.

Front 36

medial geniculate nucleus

Back 36

Part of the thalamus that relays auditory signals to the temporal cortex and also receives input from the auditory cortex.

Front 37

middle canal (scala media)

Back 37

Tympanic and vestibular canals, containing the cochlear partition.

Front 38

middle ear

Back 38

An air-filled chamber containing the middle bones or ossicles. The middle ear conveys and amplifies vibration from the tympan­ic membrane to the oval window.

Front 39

mid-spontaneous fibers

Back 39

Auditory nerve fibers with medium rates (10–30 per second) of spontaneous firing. The characteristics of mid-spontaneous fibers are intermediate between low-spontaneous fibers and high-spontaneous fibers

Front 40

organ of Corti

Back 40

A structure on the basilar membrane composed of hair cells and dendrites of auditory nerve fibers.

Front 41

primary auditory cortex (A1)

Back 41

The first area within the temporal lobes of the brain responsible for processing acoustic information.

Front 42

psychoacoustics

Back 42

The study of the psychological correlates of the physical dimensions of acoustics; a branch of psychophysics.

Front 43

rate–intensity function

Back 43

A map plotting the firing rate of an auditory nerve fiber in response to a sound of constant frequency at increasing intensities.

Front 44

rate saturation

Back 44

The point at which a nerve fiber is firing as rapidly as possible and further stimulation is incapable of increasing the firing rate.

Front 45

Reissner’s membrane

Back 45

A thin sheath of tissue separating the vestibular and middle canals.

Front 46

round window

Back 46

A soft area of tissue at base of the tympanic canal that releases excess pressure remaining from extremely intense sounds.

Front 47

sensorineural hearing loss

Back 47

Hearing loss due to defects in the cochlea or auditory nerve.

Front 48

sine wave

Back 48

A waveform for which variation as a function of time is a sine function. Also called pure tone. Compare complex tone

Front 49

spectrum (pl. spectra)

Back 49

A representation of the relative energy (amplitude) present at each frequency.

Front 50

stapedius

Back 50

The muscle attached to the stapes in the cochlea; tensing the stapedius decreases vibration.

Front 51

stapes

Back 51

The third ossicle; connected to the incus on one end, the stapes presses against the oval window of the cochlea on the other end.

Front 52

stereocilia (s. stereocilium)

Back 52

Hairlike extensions on tips of hair cells that initiate the release of neurotransmitters when they are flexed.

Front 53

superior olive

Back 53

An early brain stem region in the auditory pathway where inputs from both ears converge.

Front 54

tectorial membrane

Back 54

A gelatinous structure attached on one end, extending into the middle canal floating above inner hair cells and touching outer hair cells.

Front 55

temporal code

Back 55

Tuning of different parts of the cochlea to different frequencies, in which information about the particular frequency of an incoming sound wave is coded by the timing of neural firing as it relates to the period of the sound. Compare place code.

Front 56

temporal integration

Back 56

The process by which a sound at a constant level is perceived as being louder when it is of greater duration. The term also applies to perceived brightness, which depends on the duration of light.

Front 57

tensor tympani

Back 57

The muscle attached to the malleus; tensing the tensor tympani decreases vibration.

Front 58

threshold tuning curve

Back 58

A map plotting the thresholds of a neuron or fiber in response to sine waves with varying frequencies at the lowest intensity that will give rise to a response.

Front 59

timbre

Back 59

The psychological sensation by which a listener can judge that two sounds that have the same loudness and pitch are dissimilar. Timbre quality is conveyed by harmonics and other high frequencies.

Front 60

tonotopic organization

Back 60

An arrangement in which neurons that respond to different frequencies are organized anatomically in order of frequency.

Front 61

two-tone suppression

Back 61

A decrease in the firing rate of one auditory nerve fiber due to one tone, when a second tone is presented at the same time.

Front 62

tympanic canal (scala tympani)

Back 62

A fluid-filled passage that extends from the round window at the base of the cochlea to the helicotrema at the apex.

Front 63

tympanic membrane

Back 63

The eardrum; a thin sheet of skin at the end of the outer ear canal. The tympanic membrane vibrates in response to sound.

Front 64

vestibular canal (scala vestibuli)

Back 64

A fluid-filled passage that extends from the oval window at the base of the cochlea to the helicotrema at the apex.

Front 65

volley principle

Back 65

An idea stating that multiple neurons can provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but does not fire on every period.

Front 66

white noise

Back 66

Noise consisting of all audible frequencies in equal amounts. White noise in hearing is analogous to white light in vision, for which all wavelengths are present.