More CANS Flashcards
What are the structures of CANS?
8CSLIMA
CN 8
Cochlear nucleus
Superior olivary complex
lateral laminiscus
inferior colliculus
medial geniculate body
a1
what kind of receptors are our hair cells?
mechano receptors
what pivots on stereocilia during mechanical stimulation/sheering
cross-linked actin filaments
do stereocilia move independently?
no, they are interlinked and move as a whole bundle
what do the tiplinks have
mechanically-gated cation channels normally open part of the time
What causes the rush of potassium into the hair cell (depolarization)?
stereocilia are deflected shortest to tallest
causes increased firing
depolarization
causes decreased firing
hyperpolarization
what is an important accessory structure?
tectorial membrane
aids in response to sounds
what do our OHCs do
biological mechanical amplifiers
describe upward scale of masking
low frequencies mask the high frequencies
low frequencies have a more gradual slope where high frequencies have a steeper slope
main sensory/afferent fibers
IHC
How many CN VIII fibers go to IHC
90-95%
___ IHC synapses onto _____ different CN VIII fibers
1, 10
amplifiers
OHC
Receives ___ innervation from afferents
5-10%
___ CN VIII fibers attaches to ____ OHCs
1, multiple
divergent
goes from one hair cell to many nerve cells
convergent
goes from a bunch of hair cells to one nerve cell
information ____ to many neurons from one IHC
diverges
information from many OHC _____ on to one neuron
converge
What type of cell do we mostly see on CN VIII fivbers? Explain them
bipolar - two parts, dendrite to pick up and bring it along pathway to cell body then axon going down to terminal boutons to synapse
cell body = spiral ganglion
receive info from cochlea
spiral ganglion = cell body in cochlea spiral
axon runs through IAC (CNS) - cochlear nucleus
What are key factors of AP?
Voltage-gated ion channels
All or none depolarization
Self-propagating—one spot triggers the next spot
Moves forward only (naturally) due to absolute and relative refractory periods
Jumps by salutatory conduction from node of Ranvier to the next node
How do we encode?
frequency, intensity, firing patterns for onset, duration, offset, envelope
Describe frequency encoding
tonotopic organization and phase locking (related to timing and frequency)
Describe intensity encoding
rate of firing of action potentials, how many fibers are firing and which fibers are firing
A plot which represents the “tuning” or frequency specificity of response
tuning curve
What responds to get tuning curves?
BM, nerve fiber/cell, psychoacoustic response of a PT
firing patterns over time
post-stimulus time histogram
