chapter 11 sensation and perception

auditory response area

the psychologically measured area that defines the frequencies and sound pressure levels over which hearing functions. this area extends between the audibility curve and the curve for the threshold of feeling

loudness

the quality of sound that ranges from soft to loud. usually increase with dB

acoustic prism

the way the cochlea separates frequencies entering the ear to create activity at different places along the basilar membrane

inner hair cells

auditory receptor cells in the inner ear that is responsible for auditory transduction and the perception of pitch

outer hair cells

auditory receptors cells that amplify response of inner hair cells by amplifying vibration of basilar membrane

temporal coding

connection between frequency of sound stimulus and timing of the auditory nerve fiber firing

periodicity pitch

constancy of complex tone's pitch when fundamental frequency and other lower harmonics are remvoed

frequency tuning curve

curve relating to frequency and the threshold intensity for activating an auditory neuron

frequency

the number of times per second that pressure changes of a sound stimulus repeat. Is measured in Hz where 1 Hz is one cycle per second

sound

either physical stimulus for hearing (sound wave) or the perceptual experience of hearing

cochlear amplifier

expansion and contraction of the outer hair cells in response to sound sharpens the movement of the basilar membrane to specific frequency. this Amplifying effect plays an important role in determing the frequency selectivity of auditory nerve fibers

phase locking

firing auditory neurons in synchrony with phase of an auditory stimulus

resonant frequency

frequency most strongly enhanced by resonance.

amplitude

in the case of a repeating sound wave, such as the sine wave a pure tone, amplitude represents the pressure difference between atmospheric pressure and the maximum pressure of the wave

place theory of hearing

theory where sound is indicated by place along the organ of corti at which nerve firing is highest based on Bekesy's traveling wave theory

leisure noise

noise associated with leisure activities

pitch neuron

neurons that respond to specific pitch

audibility curve

a curve that indicates the sound pressure level (spl) at threshold for frequencies across the audible spectrum

equal loudness curve

a curve that indicates the sound pressure levels that result in a perception of the SAME loudness at frequencies across the audible spectrum

presbycusis

a form of sensorineural hearing loss that occurs as a function of age ans is associated with decrease in hearing high frequencies

cochlear partition

a partition in the cochlea extending almost its full length that separates the scala tympani and the scala vestibuli. the organ of corti which contains the hair cells is part of this

frequency spectrum

a plot that indicates the amplitude of the various harmonics that make up a complex tone. Each harmonic is indicated by a line that is positioned along the frequency axis with the height of the line indicating the amplitude of the harmonic

fundamental

a pure tone with frequency equal to the fundamental frequency of a complex tone

periodic tone

a tone whose wave form repeats

pure tone

a tone with pressure changes that can be described as a sine wave

organ of corti

major structure in cochlea partition. contains basilar membrane, tectorial membrane, and receptors for hearing

tympanic membrane

membrane at the end of the auditory canal that vibrates in response to vibrations of the air and transmits these vibrations to the ossicles in the middle ear also called eardrum

basilar membrane

membrane that stretches the length of the cochlea and controls the vibration of the cochlear partition

tectorial membrane

membrane that stretches the length of the cochlea and is located directly over the hair cells (roof) vibrations of cochlear partition cause this membrane to bend the hair cells

middle-ear muscles

muscle attached to ossicles in middle ear.

tonotopic map

ordered map of frequencies...along the cochlea...apex responds to high and base responds to low

base (of cochlear or basilar membrane)

part of the cochlea nearest the middle ear

sound wave

pattern of pressure changes in environment

tone chroma

perceptual similarity of notes separted by one or more octaves

higher harmonics

pure tones with frequencies that are whole-number multiples of the the fundamental frequency

harmonic

pure-tones components of a complex tone that have frequencies that are multiples of the fundamental frequency

pitch

quality of sound ranging from low to high most closely related to frequency

timbre

quality that distinguishes btw notes that have the same pitch, loudness and duration. ex) musical instruments

effect of missing fundamental

removing the fundamental frequency and other lower harmonics from a musical tone does not change the tone's pitch (periodicity pitch)

resonance

resonance is the enhancement of sound frequency through reflection of sound wave

oval window

small membrane coverd hole in cochlea that receives vibrations from the stapes

cochlea

snail-shaped liquid filled structure that contains the structures of the inner the most important of which are the basilar membrane , tectorial membrane, and the hair cells

tip links

structures at the top of cilia that when bent cause CA+ channels to open/close and change physical energy to chemical energy

attack

the build up of sound energy that occurs at the beginning of a tone

auditory canal

the canal through which air vibrations travel from the environment to the tympanic membrane

decay

the decrease in the sound signal that occurs at the end of tone

apex (of the cochlea or basilar membrane)

the end of the cochlea farthest from the middle ear

fundamental frequency

the first harmonic of a complex tone; usually the lowest frequency in the frequency spectrum of a complex ton. tone's other components called higher harmonics have frequencies that are multiples of this

characteristic frequency

the frequency at which a neuron in the auditory system has its lowest threshold

tone height

the increase in pitch that occurs as frequency is increased

octave

tones that have frequencies that are binary multiples of each other

hertz (Hz)

unit for designing the frequency of a tone. one equals one cycle per second

traveling wave

vibration in the basilar membrane in which the peak of the vibration Travels from the base of the membrane to the apex