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;
16 Cards in this Set
- Front
- Back
|
Sound characteristics |
= spherical 3D pressure waves generated by vibrating air molecules - amplitude ~ loudness, dB = 20 log[P/P(o)], <140 - frequency ~ pitch; humans: 20 Hz - 20 kHz - complexity ~ timbre |
|
|
Presbycusis |
= hearing loss that occurs in old age |
|
|
Auditory conductance in ear |
External ear - auricle - helps collection of sound - external auditory meatus: 30-100x boost Middle ear - E boost 200x: air -> fluid, large TM -> o. window - attenuation reflex - tensor tympani (CN V) & stapedius (CN VII) mm.'s; loss -> hyperacusis - connection to nosopharynx via ET |
|
|
Basilar membrane |
= base of scala media (stria vascularis -> endolymph: ↑[K], 80mV) of cochlea w/ hair cells - narrower & stiffer @ base -> high frequency - wider & more flexible @ apex -> low frequency => tonotopic map of frequency - also vary in morphology: RA, BMP7 -> fewer, longer stereocilia -> low freq. |
|
|
Organ of Corti |
Hair cells (-45 mV) Support cells Tectorial membrane (gelatinous) <- stereocilia of hair cells: - tip links -> K channels |
|
|
Hair cells |
Stereocilia - deflected away from kinocilia -> hyperpolarize - deflected toward kinocilia -> depolarize Inner -> afferent -> CN VIII (1:3 - I:O) Outer (electromotile)<- efferent<- superior olive - moleculaar motor = prestin; dampen & amplify |-- furosemide |
|
|
Transduction |
Oval window -> perilymph -> basilar membrane -> endolymph & stereocilia (toward kinocilia) -> tip links -> K channels open (@ -125 mV) -> K into cell -> depolarize -> Ca -> NT release |
|
|
Auditory pathway |
Afferent nerves (inner cells) -> spiral ganglion -> CN VIII -> tonotopic organization in brainstem -> dorsal cochlear nuclei: frequency -> ventral cochlear nuclei: localization -- lateral time delay -> medial superior olive -- intensity difference -> lateral s. o. (MNTB) -> inferior colliculus: integration w/ somatosen. -> thalamus (M geniculate) -> temporal lobe |
|
|
Inferior colliculus |
- integration of auditory w/ somatosensory input - filtering out self-generated sounds vs. external - auditory/space map Startle reflex Vestibulo-ocular reflex |
|
|
Processing in auditory cortex |
1° AC ~ superior temporal (& Heschl's) gyrus - tonotopic projection - columnar organization (per frequency) - cells specific for sound combinations 2° AC ~ belt A's: sound combinations processing Wernicke's A - speech comprehension, auditory association A; auditory & visual input |
|
|
Dual stream auditory processing |
Ventral stream: pitch - 1° auditory cortex - inferior frontal gyrus Dorsal stream: location - superior parietal cortex - superior frontal gyrus |
|
|
McGurk effect |
- due to the importance of interaction between auditory & visual input for speech comprehension -> confounding of similar sounds based on perceived visual input (speaker's lips) sound =/= visual input => 3rd, unrelated sound perceived |
|
|
Broca's area |
- part of CC -> projects to motor cortex => speech production & music key determination Lesion -> disorder = Broca's aphasia Connected to Wernicke's A by Arcuate Fasciculus Lesion -> Conduction aphasia |
|
|
Supramarginal gyrus |
- responsible for matching incoming sounds w/ meaningful phonemes |
|
|
Angular gyrus |
- responsible for matching graphemes w/ meaningful phonemes |
|
|
Auditory disorders |
Presbycusis - old age hearing loss <- loss of hair cells (esp. hi frequency) Hyperacusis - low tolerance to sounds due to mm.'s of middle ear, etc. Auditory agnosia - inability to interpret nonverbal sounds Congenital amusia = tone deafness - inability to distinguish Δ in pitch Tinitus - perception of sound in absence of stimulus Acoustic neuroma - tumors of Schwann cell origin -> hearing loss/tinitus Meniere's disease - progressive hearing loss <- excess endolymph (low f) |
