Pers&Sens Exam 2

What is a sound stimulus? What is a sound wave?

sound stimulus: periodic variations in air pressure traveling out from a source

sound wave: the waves of pressure changes that occur in the air as a function of the vibration of a source

the matter/substance in which sound travels through and is necessary to conduct sound is known as ________. How does water vs air & sound vs light travel?

the medium of sound

• in water, sound travels 4 times faster than it does through air

• sound travels fast, but slower than light

the sound waves in which air pressure changes follow a sine wave pattern are called ______

pure tones

amplitude and what unit measures it

difference between max sound and minimum sound pressures, measured by decibel (dB)

the perceptual experience of amplitude is known as _______

loudness

why can loud sounds be dangerous + what happens at 85 dB, 120 dB, and 130 dB

• prolonged contact to sounds over 85dB can cause hearing loss

• louder than 120 dB is painful

• louder than 130dB results in immediate/permanent hearing loss

the time between one peak of high pressure and the next, measuring the number of cycles in a sound that occurs in 1 second is known as ____________, and the physical distance between two consecutive identical points on a wave is known as ____________. What’s the relationship between these two things?

frequency; wavelength of sound

• As frequency increases, wavelength decreases; as frequency decreases, wavelength increases

_______ is the subjective experience of frequency and _____ is used to measure it, and it indicates what? Hz

Pitch; Hz: number of cycles per second

children/young adults can hear from _____ to ______, which is known as the hearing range of humans. With age, ________ hearing range dissipates, at 50, the upper limit is around _________, and ________ frequencies tend to remain stable with age hearing range of humans and how the range changes with age

20 to 20,000 Hz (hearing rnage of humans); highest hearing range dissipates; upper limit at 50 is 12,000 Hz; lowest frequencies remain stable with age

hearing loss may be worse when someone…

had exposure to loud sounds while young

outer ear parts

• pinna

• external auditory canal

• tympanic membrane (eardrum)

function of the pinna

collects sound and funnels it to the auditory canal

function of the external auditory canal

conducts sound from pinna to tympanic membrane, amplifies specific sound frequencies

function of the tympanic membrane (eardrum)

thin elastic sheet that vibrates in response to sounds from external auditory canal

middle ear parts

• eustachian tube

• tensor tympani

• stapedius

• ossicles: malleus (hammer), incus (anvil), and stapes (stirrup)

function of the eustachian tube

connects middle ear with pharynx; equalizes air pressure on either side of eardrum

function of the tensor tympani/stapedius

these muscles attached to malleus and stapes tense in presence of very loud noises

function of the ossicles

conduct sound mechanically to amplify sounds; includes three small bones in inner ear

function of malleus (hammer), incus (anvil), and stapes (stirrup)

malleus (1st ossicle) receives vibrations from the tympanic membrane, transmits them to the incus (2nd ossicle), the incus then transmits them to the stapes (3rd ossicle), and the stapes transmits them to the inner ear

inner ear parts (cochlea, and inside the cochlea)

Cochlea:

• tympanic canal

• middle canal

• vestibular canal

• Reissner’s membrane

• basilar membrane

• tectorial membrane

(inside cochlea :) Organ of Corti:

• hair cells: stereocilia: has inner and outer hair cells

hair cells are located along the _______, and they do what?

Organ of corti; receive vibrations and convert them into neural signals

function of cochlea

snail-shaped structure in inner ear for hearing and sound processing

the tympanic canal, middle canal, and vestibular canal are _________ that do what?

liquid filled chambers; help with balance and detecting head movement

the Reissner’s membrane seperates the _______ and ______, and it is for what?

vestibular and middle canals; for fluid separation

the basilar membrane has _____ that do what? The tectorial membrane causes the ______ to _______

fibers; transmit mechanical input of sound; basilar membrane; vibrate

stereocilia

hairlike parts of hair cells on top of inner and outer hair cells

function of inner and outer hair cells

inner: transduce neural signal/sending info to the brain

outer: receiving info from brain; can suppress noise when stiff and tune to a given frequency when not stiff

small amplitude sounds

• small displacements along cochlea

• tectorial membrane will shear across organ of Corti less forcefully

• hair cells will bend to smaller degree = less NT released

large amplitude sounds

• large displacements along the cochlea

• tectorial membrane will shear across organ of Corti more forcefully

• hair cells bend to larger degree = more NT released

how and where is frequency coded?

how: place coding/temporal coding

where: cochlea and auditory pathways

Place code theory

different locations along basilar membrane respond to different frequencies

Characteristic frequency of the basilar membrane of the cochlea

the frequency to which any particular location on the basilar membrane responds best

frequency and displacement along basilar membrane is defined by _________

tonotopic organization

___________ explains that frequency representation occurs because of a match between sound frequency and firing rates of auditory nerve

temporal code theory

6 steps of a tuning curve for an auditory nerve fiber

1. find lowest point on curve

2. read frequency

3. find what frequency neuron responds to strongly

4. neuron’s response will signal to brain that frequency is same as 3

5. This is the neuron’s characteristics frequency

6. rest of red curve has higher values on Y-axis, meaning that higher intensities of sounds are needed to observe a response higher than baseline from that neuron

the cochlear nucleus is responsible for __________

lateral inhibition (sharpen a frequency by inhibiting the response to nearby frequencies)

the trapezoid body helps do what?

determine the direction of sound

function of superior olives

receives info from both ears; critical for sound localization

sound info from the brain passes through the _______ and then to the auditory cortex

inferior colliculus

the __________ processes sound signals then sends them to the cerebral cortex

medial geniculate nucleus

Auditory pathway

cochlea → auditory nerve → cochlear nucleus → then to contralateral (dominant, brain path on opposite side of ear) or ipsilateral path (brain path on same side as ear)

auditory info projects to the _________auditory cortex & the primary auditory cortex located within the ____________ is responsible for what?

auditory cortex; temporal lobe; the primary auditory cortex receives input from the medial geniculate nucleus, and both ears project to both sides

when neruons organize within a region in the brain according to different frequencies in which they respond, this is known as __________, and the __________ displays this. What other areas are involved in auditory processing (5 areas)?

tonotopic organization; primary auditory cortex; other areas include:

• auditory core region

• rostral core

• rostrotemporal core

• belt

• parabelt areas

what and where pathways of hearing

what (ventral): speech perception and music perception

where (dorsal): localization of sound in space

What is hearing loss, what tests hearing loss

• Reduced ability or inability to hear in one or both ears

• audiometer tests hearing; the result is an audiogram

sensorineural hearing loss is _______ and can be caused by what? What is tinnitus

permanent; damage to the cochlea, auditory nerve, primary auditory cortex, or hair cells; perceiving sounds when none are present

conductive hearing loss, it’s 3 potential causes, and what is otosclerosis?

conductive hearing loss: sound doesn’t reach the cochlea (damage to the auditory canal, torn tympanic membrane, or damage to ossicles)

Otosclerosis: calcification of the ossicles

what are hearing aids and cochlear implants and who are they for

hearing aid: amplifies acoustic sound (for mild to severe hearing loss)

cochlear implant: converts sound into electrical signals, directly stimulating the auditory nerve (for severe sensorineural hearing loss when hearing aids will work for them)

the collection of frequency components whose values are all whole-number multiples of a single lowest frequency is known as the ________

harmonic spectrum

When the brain perceives the lowest frequency of a harmonic series (the fundamental frequency) even when that frequency is completely removed from the sound, this is referred to as the ________

missing fundamental effect (residue pitch)

The perceived sound differences between different instruments even when playing the same pitch (quality of sound) is known as ________

timbre

Changes in acoustics/changes in the onset and offset of sound affect how we perceive which things?

timbre, articulation, and identity (e.g. sharp transition/abrupt stop, vs smooth flow)

how sound localization works and what does it use

Ears detect differences in how acoustic waves reach the left and right ear; uses interaural level/time differences

Interaural level difference

difference in loudness and frequency distribution between two ears (difference in amplitude between two ears)

Interaural time difference

time interval between when a sound enters one ear and when it enters the other ear (e.g. left or right ear first?)

the media superior olives are ________ to time differences; how is interaural time difference computed in the medial superior olives (3 steps)?

sensitive; Sound → cochlear nucleus → synapse in medial superior olives where info from right/left cochlea is combined

what is the cone of confusion?

A perceptual blind spot where sounds create the same interaural time and interaural level differences

elevation perception, what it helps with, & spectral shape cue provides info about _____

sounds coming from above us or below us, helps with spatial localization and detecting distance from a sound; elevation

reverberation vs echo

reverberation: brain perceives one continuous sound, sound 2 detected (<40/50 ms)

echo: brain perceives separate repetition of a sound (>50 ms)

relationship between sound frequency and its travel distance + example

Low-frequency sounds travel much farther than high-frequency sounds because they lose less energy to the environment (e.g. club music, only hear rumbles from far away)

identifying specific sound-producing objects from a set of sounds from different objects at varying and overlapping frequencies is known as ____________

auditory analysis

spatial segregation

sounds coming from same location grouped together, and sounds coming from different locations not grouped together

temporal segregation

sounds linked in time grouped together, and sounds not correlated with one another not grouped together

spectral segregation

sounds that overlap in harmonic structure grouped together, and sounds that do not overlap in harmonic structure are not grouped together

spectral sensitivity

if harmonics are provided through different sources, the brain combines them and we hear one sound, if sounds aren’t perfect harmonics, this will not work

what is the brain doing to achieve sound restoration

brain filling in missing auditory info

function of vestibulo-spinal reflex and where this happens

balance and postural control through organs inside ear

function of visual stability & what’s its also called

Perceive a steady world even though our body and eyes constantly move; aka vestibulo-ocular response

function of regulation of blood pressure & what the vestibulo-autonomic reflex is

• Adjusting how much oxygen goes to the brain when moving

• Vestibulo-autonomic reflex: communicates between the inner ear and the nervous system

what info does the vestibular system provide? Location of vestibular system in the human body?

balance and spatial orientation; located in inner ears

what are the vestibular organs

• 3 semicircular canals (anterior, posterior, horizontal)

• 2 otolith organs: utricle and saccule

vestibular organs detect what? They do not respond to what?

detect changes in acceleration/movements of any amplitude in any direction (forward, sideways, upward, etc.)

• don’t respond to constant velocity

function of hair cells inside the vestibular organs, and what does each hair cell have?

• transduce mechanical movements into neural energy

• Each hair cell has stereocilia

How stereocilia work when head is at: resting state, when head movements occur, depolarization, and hyperpolarization

resting: stereocilia not bent

• head movements cause stereocilia to bend, and causes a change in voltage

depolarization: stereocilia bend in the direction of kinocilium

hyperpolarization: stereocilia bend in the opposite direction of kinocilium

the otolith organs are the organs responsible for what?

detecting acceleration of the head and identifying when the head is being held at a tilted angle (linear acceleration and gravity)

the utricles contain 30,000 _______ that detect changes in ________ acceleration, whereas the saccules contain 15,000 _______ and detect changes in ________ acceleration

hair cells; horizontal; hair cells; vertical

the otoconia contains crystals lying on top of a gelatinous layer known as the _______ that detect ___________. the striola is a band that determines ____________. Deflection of hair cells is caused by ___________ due to __________

otolithic membrane; linear acceleration, head tilt, and gravity; the direction of the kinocilium; displacement of the otoconia; linear acceleration and gravity

the hair cells are embedded in the ___________, and they do what?

gelatinous layer; convert movement into electrical signals

the semicircular canals sense _____________. The three canals are ________________. When the head is rotated, _______ in the canals does what?

rotational movements; anterior, posterior, and horizontal; Fluid; moves in one or more canals

each canal has an _________ that hold the hair cells, and each _______ contains a _________, which is a ___________. The bottom part of the _________ is known as the ________, which contains ~7000 hair cells involved in transduction

ampulla; ampulla; cupula, gelatinous membrane; cupula; crista

hair cells’ _________ will ______ in response to fluid movement

stereocilia; bend

different rotations cause hair cells __________ in one or more canals. The push-pull effects state that….?

deflection; one ear has depolarized hair cells, the other ear has hyperpolarized hair cells (opposite arrangement)

When the head is turned to the left vs right, what happens? Where does endolymph move and which ear is depolarized/hyperpolarized?

head turns to left: endolymph moves to the right, left ear depolarized, right ear hyperpolarized

head turns to right:endolymoh moves to the left, right ear depolarized, and left ear hyperpolarized

the more hair cells bend, the larger the change in ________, and higher amplitude movements have a __________ change in voltage than __________

voltage; larger; small amplitude movements

when angular acceleration changes __________ over time, this means that the rate at which an object speeds up or slows down its rotation oscillates smoothly

sinusoidally

the cupula deflects based on the ________ of _________ during ___________. During acceleration, the cupulla bends in ________ of _________, and in deceleration, the cupulla gets pushed in _________ of when it was ___________

inertia; surrounding fluid (endolymph); acceleration and deceleration; the opposite direction of head movement; the opposite direction of when it was accelerated

experienced speed of turning; when exiting a merry-go-round, this results in the _________ associated with __________

illusion of self-rotation; deceleration

exponent for turning sensation

around 1.3 (—> response expansion)

passive translation

participant physically moved through space by external force

how the perception of tilt works (30 degrees)

if tilted 30 degrees to the right, and someone perceives it as 30 degrees to the right, this means someone has an accurate tilt perception

what is vestibular neuritis, what causes it, and what is its symptom

• This is the disease that causes vertigo

• caused by an inflammation of the vestibular nerve

• Symptom: vertigo

What is vertigo, what causes it, and what are it’s symptoms?

vertigo is a symptom, a feeling

Causes: benign paroxysmal positional vertigo (BPPV): small calcium particles accumulate in canals

Symptoms: feel as if world is spinning, off-balance, dizziness, nausea, vision difficulty

what causes labyrinthitis, and what are its symptoms

Causes: inflammation of vestibular and cochlear nerve

Symptoms: vertigo, tinnitus, and/or hearing loss

causes and symptoms of motion sickness

Causes: disagreement between the vestibular organs and vision

Symptoms: feeling sick, nausea, dizziness, headaches

illusion of self-motion (vection), example and cause

example: standing on beach, staring down at wave going back into ocean, makes you feel like you are moving

Cause: Eyes sense movement, but the vestibular sense does not

definition of light

psychological experience of amount of light that gets reflected by a surface; electromagnetic energy

wavelength is the _________, intensity is the ____________, and frequency is the ___________

distance between peaks; height of the wave; number of waves per unit of time

properties of light

• scattered/diffracted

• absorbed

• reflected

• transmitted

• refracted

human field of view in degrees (sides, up, and down)

110 degrees to side visible to both eyes, 60 degrees up, and 80 degrees down

the _______ is the protective membrane of the eye, and the _____ is the clear surface that focuses light towards the retina, and the _______ is within the cornea. The _____ is the c olored muscle in the eye, and the ______ is it’s opening

sclera; cornea; anterior chamber; iris; pupil