Study shit

The auditory nerve fibers form the cochlear portion of which cranial nerve

8th

What happens to the discharge rate when the ANF is stimulated by sound?

Discharge rate increases

What is the dynamic range of most ANFs

20-50 dB

What there is no sound, ANFS discharge at their ____

Spontaneous discharge rate

Each Inner hair cell has approximately ___ auditory nerve fibers connecting to it

20

Where is response magnitude measured within a PST histogram?

Steady state part of the response

When looking at a PST histogram, as a stimulus level ___, discharge rate ___

Increases, Increases

A graph that shows the ANF discharge rate during the presentation of a sound stimulus

Post stimulus time (PST) histogram

Threshold refers to the intensity level where the ANF first responds

True

Saturation refers to the intensity level where the firing level starts growing as the stimulus level decreases

False

Thresholds of ANFs are staggered over a range of about ___ dB

60

What is Phase Locking?

Firing on the excitatory phase of the stimulus

Label the major parts of the brain, lobes of the cerebral cortex

Brainstem

Cerebellum

Cerebrum

Frontal

Parietal

Temporal

Occipital

Limbic Lobes

Frequency is coded by ____ and also coded through a secondary mechanism called ——?

Place of stimulation, Phase locking

The major pathways are crossed

Truth

Sound is processed in which lobe of the brain?

Temporal lobe

Things are ordered organized ___ in the auditory cortex

Tonotopically

Method of Limits

Stimulus is presented

Subject indicates whether they heard it or nah

Tester manipulated level of stimulus based on this response

Threshold is determined by averaging “crossover points” of ascending and descending runs

Method of Adjustment

(Similar to Method of Limits)

Subject control stimulus level by turning an unmarked knob

Stimulus changes in continuous fashion

Does NOT have fixed steps

Method of Constant Stimuli

Various stimulus level in random order with equal stimuli in each level

Psychometric function is constructed to determine threshold

What is psychometric functions?

Graph that displays relationship between physical stimulus

For example: Level (dB SPL) and listeners behavioral response probability

Minimum audible pressure

Measure thresholds for one ear using headphones

Minimum audible field thresholds (MAF)

Measured using speakers

Sounds are heard by both ears at the same time for threshold measurement

MAF thresholds are 6dB lower and better than MAP thresholds due to binaural summation

In what of Hz is hearing sensitivity the best

2000 - 5000 HZ

What is the total range of human hearing sensitivity? (Lowest frequency that can be heard up to the highest frequency that can be heard)?

20 - 20000 Hz

When is hearing sensitivity poor?

Below 100 hz and above 10,000

How does binaural summation affect MAF thresholds and MAP thresholds?

When sound is presented to two ears

MAF thresholds tend to be 6 dB lower

Why is sound perceived softer as it gets shorter? Even though the actual level stays the same?

Temporal integration

What is binaural summation?

Occurs when sound is presented to two ears instead of one

What is the difference between MAP (minimal audible pressure) and MAF (minimum audible field)

Map is based on one ear thresholds with headphones while Maf is based on using two ear thresholds from speakers

At what dB SPL do sounds become uncomfortably loud?

100 dB SPL

As a sound gets shorter does the threshold become higher or lower?

Becomes higher

The sound is also being perceived as being shorter

What is temporal summation/integration?

Trading of duration and intensity

When sounds are shorter than 200 MS

Threshold or loudness depends on duration

Absolute Difference (DL)

Smallest perceptible difference between two sounds

Relative Difference Limen

Considers the DL and the starting point

What is the equation for the weber fraction?

Absolute DL divided by the starting point

What range is frequency discrimination the best, for the Weber Fraction ?

600 - 2000

Intensity difference limens

Webers fraction decreases slightly with increasing intensity

At higher levels loudness perception grows faster

What is critical bandwidth? CBW

Bandwidth at which a perceptual change occurs

Critical bands are ___ for higher frequencies and ___ for lower frequencies

Larger, Smaller

CBW

Illustrates that in addition to other factors, bandwidth also plays a role in loudness perception

Pitch and Loudness are ___ attributes of sound

Perceptual

Level (dB SPL) and frequency are ___ attributes of sound

Physical

Pure tone sounds that are less than 5 millisecond in duration sound like __

Clicks

A person is presented with a complex sound with harmonics at 600 Hz, 800 Hz, 1000 hZ, and 1,200 Hz, and asked to match the pitch of the sound to a pure tone. The person will match the pitch to approximately __?

200 Hz

A 500 Hz tone and a 505 Hz tone are presented at the same time, and the same level. The resulting sound will:

Beat in amplitude at a rate of 5 Hz (5 times per second