Exam 1 Sensation and Perception

Decibel scale is a

log scale describing sound pressure level

Human hearing is sensitive around

4000

compression

higher air pressure (top)

rarefactions

lower air pressure (bottom)

Fourier Analysis

breaking complex sounds into pure tones

Fourier Synthesis

adding pure tones together to make complex sound

spectrogram

Spectrum is plotted over time

harmonics

the lines above the lowest horizontal line in a spectrum

fundamental frequency

the lowest horizontal line in a spectrum

What does the darkness of the lines in a spectrum

amplitude

equal loudness curves

Curves where each one represents amplitude and frequency combos that sound equally loud.

acoustic reflex

muscles tense with loud sounds and self-generated sounds (chewing)

Afferent cranial nerve

cranial nerve 8

Efferent cranial nerves

Cranial nerve 5 and 7

First way middle ear amplifies sound

the angle of articulation between ossicles allows them to work as levers

Second way middle ear amplifies sound vibrations

concentrates energy from large surface area of ear drum to smaller surface area of oval window.

Ototoxicity

Hair cell damage caused by drugs that are toxic to ICH’s, OHC’s or both

Otoacoustic emission

Sound generated by OHC causing backward propagation of wave through vestibular canal, oval window, and ossicles. Occurs in response to sound and is measured with instrument in ear canal

Place theory

Different frequencies displace different regions of the cochlear partition.

Phase locking

Auditory nerve fibers lock on to a part of a sound wave and fire each time it occurs. Allows fibers to fire at rate to match frequency of sound.

Volley principle

multiple hair cells/fibers work together to frequency match a sound that is too high frequency for any of them to do alone

Characteristic frequency

Lowest point in 2-tone suppression graph, as it is the smallest amplitude

What tones displace more locations of the cochlear membrane

complex tones

Which sounds displace more of the cochlear partition and activate more hair cells

loud sounds

When an auditory nerve fiber is stimulated by amplitudes well above threshold it will respond…

to its characteristic frequency and to frequencies above/below its characteristic frequency

When an AN fiber is stimulated by amplitudes well above threshold it will respond with…

max rate of firing

The firing rate of AN fibers depend on

the amplitude AND frequency of the stimulus

Afferent axons

axons that synapse with inner hair cells send information to the brain

Efferent axons

axons that synapse with outer hair cells send information from the brain

3 cochlea canals

vestibular, middle, and tympanic canal (clockwise)

3 cochlear membranes

Reissner’s, basilar and tympanic

Across-fiber patterning

each active AN fiber is only conveying a piece of the info so brain must put together what is coming from all the other fibers

Labeled line coding

The brain gets specific and accurate info regarding the frequency of the sound based on which AN fiber is active.

2-tone suppression

When multiple frequencies are present in a sound, the responses of AN fibers is different/smaller than if they were stimulated by a pure tone. Due to mechanical changes in the basilar membrane

Timbre

The perceptual quality of a sound, which depends on the frequency and intensity of the harmonics as well as other aspects of the sound such as attack and decay

what part of the ear breaks down a sound

cochlea

The most important factor in how much of a pitch difference we will perceive between 2 tones is

percent frequency difference between the 2 tones

Wave of fluid displaces…

organ of corti where hair cells are embedded

Place code

way of coding for the frequency of high frequency sounds

Volley principle is an example of

across fiber patterning

Place code of a pure tone is an example of

labeled-line coding

Frequency matching

A way of coding for the frequency of low frequency sounds

Rate saturation causes

Labeled lined coding to no longer work because fibers can fire at a very high rate outside of their characteristic frequency

pure tones activate

primary auditory cortex

prosody

right hemisphere; musical aspects of speech

Fluent aphasia

Damage to Wernicke’s. Lack of comprehension/speaks nonsense but articulate speech

Non-fluent aphasia

Damage to Broca’s area, no articulate speech. Difficulty with motor production

Apraxia of speech

damage to broca’s area and insula; tripping over speech sounds/words