Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
69 Cards in this Set
- Front
- Back
Sense of hearing is for... |
Detecting sounds, perceive and interpret nuances |
|
Sense or balance is for... |
Head and body location, head and body movements |
|
What is sound? |
Audible variations in air pressure |
|
What is sound frequency? |
Number of cycles per second expressed in Hz |
|
What is one cycle? |
Distance between successive compressed patches |
|
Frequency range of human hearing: |
20-20,000 Hz |
|
What is intensity? |
Difference in air pressure between compressed and rarefied patches of air |
|
Auditory pathway stages: |
Sound waves TM Ossicles Cochlea fluid Sensory neuron response |
|
Brainstem nuclei output |
thalamus to A1 |
|
Middle ear: sound force amplification by the... |
ossicles |
|
Pressure: |
force by surface area; greater pressure at oval window than TM, moves fluid |
|
The acoustic reflex: |
Response where onset of loud sound causes tensor tympani and stapedius muscle contraction |
|
Function of AR: |
Adapt ear to loud sounds, understand speech better |
|
Perilymph: |
fluid in scala vestibuli and scala tympani |
|
Endolymph: |
fluid in scala media |
|
Endocochlear potential: |
endolymph electric potential 80 mV more positive than perilymph (perilymph is 0 mV) |
|
Pressure at the ______ window pushes ________ into scala vestibuli, ______ window membrane bulges out |
oval; perilymph; round |
|
Structural properties of the BM |
wider at apex stiffness decreases from base to apex |
|
Research from Georg von Bekesy |
Endolymph movement bends BM near base, wave moves towards apex |
|
Sound causes... |
BM to move upward, reticular lamina up, and stereocilia bends outward |
|
Innervation of hair cells |
one spiral ganglion fiber, one inner hair cell, numerous outer hair cells |
|
Amplification by ______ |
outer hair cells |
|
function of outer hair cells |
sound transduction |
|
motor proteins |
change length of outer hair cells |
|
prestin |
required for outer hair cell movements |
|
Auditory pathway has more _______ at nuclei and more alternative _________ than the visual pathway |
synapses; pathways |
|
Dominant pathway goes from... |
SOC to contra side (but still goes on ipsi side) |
|
Characteristic frequency of neurons in auditory pathway: |
frequency at which neuron is most responsive |
|
Response of neurons in auditory pathway: |
more complex and diverse on ascending auditory pathway in the brainstem |
|
Encoding info about sound intensity |
firing rates of neurons; number of active neurons |
|
Frequency sensitivity: |
basilar membrane |
|
Frequency |
highest at base, lowest at apex |
|
tonotopy: |
systematic organization of characteristic frequency within auditory structure |
|
Phase locking: |
Consistent firing of cell at same sound wave phase |
|
Techniques for sound localization: |
Horizontal (left-right), vertical (up-down) |
|
Localization of sound in horizontal plane |
ITDs, ILDs, duplex theory of sound localization |
|
ITD: |
time taken for sound to reach from ear to ear |
|
ILD: |
sound at HF from one side of ear |
|
Duplex theory of sound localization: |
ITD: 20-20,000 Hz ILD: 2000-20,000 Hz |
|
The sensitivity of binaural neurons to sound localization: |
Monaural, binaural, superior olive |
|
Superior olive: |
cochlear nuclei input to superior olive, greatest response to specific interaural delay |
|
Acoustic radiation: |
axons leaving MGN project to auditory cortex via internal capsule in an array structure of A1 and secondary auditory areas similar to corresponding visual cortex |
|
Neuronal response properties: |
frequency tuning; isofrequency bands |
|
Frequency tuning: |
similar characteristic frequency |
|
isofrequency bands: |
similar characteristic frequency, diversity among cells |
|
Principles in study of auditory cortex |
tonotopy, columnar organization of cells with similar binaural interaction |
|
Lesion in auditory cortex |
normal auditory function |
|
lesion in striate cortex: |
complete blindness in one visual hemisphere |
|
different frequency band information: |
parallel processing, localization deficit |
|
Importance of vestibular system |
balance, equilibrium, posture, head, body, eye movements |
|
Function of semicircular canals: |
detect head movements |
|
Structures of vestib system: |
crista, ampulla, cilia, kinocili, semicircular canals |
|
Crista: |
sheet of cells where hair cells of semicircular canals clustered |
|
Ampulla: |
bulge along canal, contains crista |
|
Cilia: |
project into gelatinous cupula |
|
Kinocilia: |
oriented in same direction so all excited or inhibited together |
|
Three semicircular canals on one side: |
-helps sense all possible head-rotation angles |
|
Each canal paired with... |
another on opposite side of head |
|
Push-pull arrangement of vestib axons: |
rotation causes excitation on one side, inhibition on the other |
|
Vestibulo-ocular reflex (VOR) function: |
line of sight fixed on visual target |
|
VOR mechanism |
senses rotations of head, commands compensatory movement of eyes in opposite direction |
|
connections from semicircular canals to.... |
vestib nucleus, to cranial nerve nuclei --> excite extraocular muscles |
|
Hearing and balance have nearly identical ____ |
sensory receptors (hair cells) |
|
Movement detectors: |
periodic waves, rotational, and linear force |
|
Auditory system: |
senses external environment |
|
vestib system: |
senses movements relative to gravity and environment |
|
auditory system parallels ______ |
visual system |
|
how? |
tonotopy (auditory) and retinotopy (visual) preserved from sensory cells to cortex code |
|
convergence of inputs from lower levels --> |
neurons at higher levels have more complex responses |