1/25 intro to auditory processing

Question 1

Features of a sine wave

Answer 1

Cycle (time between peaks), pitch (frequnecy), intensity (amplitude), phase (location at some time(

Question 2

Human hearing range and decibel

Answer 2

20Hz to 20kHz, 0 to 120 db (120/140 = damage)

Question 3

Fourier analysis

Answer 3

complex sine waves can be decomposed to combo of simple ones

Question 4

Harmoncs

Answer 4

1/n amplitude and Nx frequency (3rd harmonic = 1/3 amp and 3f)

Question 5

What is on an amplitude spectrum

Answer 5

Frequency on x and ampltidue on y, this is the fourier analysis of any complex sound

Question 6

What does a spectrogram show

Answer 6

Time, frequency, and ampltiude (darkness)

Question 7

Parts of ear

Answer 7

Outer (pinna), Middle (tympanic/bones), Inner (cochlea

Question 8

2 impedance matching mechanisms

Answer 8

Lever-arm ratio = malleus bigger than incus, lever action multiplies it
Area Ratio = main factor, tympanic membrane bigger than oval window, pressure/force area

Question 9

Attenuation Reflex

Answer 9

Onset of loud sound/talking tenses muscles to reduce decibles. Just AFTER loud sound, just BEFORE talking

Question 10

Parts of cochlea

Answer 10

Scala vestibuli/media/tympani. perilymph in vest/tym (like extracellular, low K high Na)
Endolymph in media (intra fluid, High K low Na)

Question 11

Anatomy of basilar membrane

Answer 11

Base is narrow/high freq, Apex is wide/low freq. Place coded, tonotopy

Question 12

Organ of corti movement

Answer 12

Hair cells move with basilar membrane pushed onto organ of corti

Question 13

Describe hair cell depol

Answer 13

Movement toward kinocilia depol, away hyperpol due to mechanically gated tip links that open with movement toward.
Endolymph in tip link (+80), perilymph in cell (-70) = LARGE DRIVING FORCE, small movement = big voltage change

Question 14

How encode frequency

Answer 14

Phase locking/volley for low freqs (can keep up)
Tonotopy for all freqs

Question 15

Auditory tuning curve

Answer 15

See what freqs depol to lowest intensity, characteristic frequency is where lowest threshold

Question 16

How encode intensity

Answer 16

Number of active neurons/firing rate

Question 17

How encode location

Answer 17

Interaural timing differences for LOW freqs (EE medial superior olive, coincidence detectors, LOW since wavelength has to be bigger than head).
Superior olive first place binaural!
Interaural intensity diffs for high freqs (sound shadows, EI cells lateral superior olive)
Pinna for vertical localization

Question 18

Auditory pathways

Answer 18

Tonotopic columnar organization
isofrequency bands = analyze freq
binaural bands = analyze location

Question 19

Core Auditory regions/projections

Answer 19

Core A1 respond to simple, project to Belt/Parabel for more complex

Question 20

What/where auditory

Answer 20

Similar to visual, what for ??????