neuro 2 last minute

Fovea

Most sensitive part of the eye made up of almost entirely cones

Optic Disk

Axons from the ganglion cells leave the retina here to form the optic nerve, is a notable blind spot

Ganglion cells are the only cells in the retina that_______

Fire action potentials

Photoreceptors and bipolar cells have a _______ response proportional to heir level of depolarization

Graded

Horizontal cells in eye pathway

Amacrine and horizontal cells

Layers of cells in eye

Ganglion cells, bipolar cells, photoreceptor cells

Rods

Sensitive in dim light, more common in periphery of retina, provide converging input into bipolar cells (thereby increasing input but reducing visual acuity)

Cones

Need brighter light, 1 to 1 connection to bipolar cells, color information

In the dark, _____ channels in the eye are open and kept open by ______, releasing ______

Sodium, cGMP, glutamate

In the dark, the membrane potential of photoreceptors is:

depolarized

In the light, ______ channels are less permeable, as light activates an enzyme called _________ which breaks down cGMP

sodium, phosphodiesterase, cGMP

In the light, the membrane potential of photoreceptors is:

Hyperpolarized

Ganglion and Bipolar cells both have:

center-surround receptive fields

Opponency color theory

Red vs green, blue vs yellow

Yellow is made from:

Red and green

3 types of retinal ganglion cells

Parasol, Midget and Small bistratified cell

Parasol cell

Also known as M-type for magno, contributes to luminance pathway, better for quick detection and motion

Midget cell

Also called P-type, contributes to red-green channel, better for processing color and form more

Small bistratified cell,

contributes to blue-yellow koniocellular pathway

Magno/M-type/Parasol cells are in layers

1-2

Parvocellular/P-type/Midget cells are in layers

3-6

Koniocellular cells are in layers

K1-K6 underneath respective layers of M and P layer

Biaural cues in ears

ITD and ILD, based on difference of sound reception in left and right ears

Spectral cue

HRTF

ITD

Difference in time taken to reach each ear, mainly at LOW SOUND FREQ

ILD

Difference in sound pressure between each ear, the lower the frequency the less difference (functions at high frequency, MAINLY AT HIGH SOUnd FREQ

HRTF

Specifies how body receives sound, puts a vertical cue on sound, think sound bouncing off ear

Ossicle associated with tympanic membrane

Malleus

Ossicle associated with oval window

Stapes

Outer hair cells

Amplify movement of basilar membrane, protects from overstimulation

Apex of basilar membrane

Wide and floppy, better for low freq

Base of basilar membrane

Narrow and stiff, max movement at low-freq

Tip link

Protein filaments connecting successive sterocilia

Hair cells depolarize when deflecting ________ kinocilium

towards

Hair cells hyperpolarize when deflecting _____ from kinocillium

Away

_______ influx after depolarization in hair cells leads to _______ release

Calcium, glutamate

At low frequencies, neurons firing experience __________-

phase-locking

At high frequencies, neurons firing do not experience_____

Phase-locking

Superior olive

Earliest point at which ITD and ILD (biaural cues) are encoded and when BOTH EARS’ INPUT IS RECIEVED

Three regions of auditory cortex

Core, belt, parabelt

Core responds to

Pure tones

Belt responds to

Intermediate complexity sounds

Parabelt responds to

Complex sounds like speech

Superior temporal gyrus is important for processing

phonemes

Posterior superior temporal gyrus (STG) represents _______ speech sounds

fast varying

Anterior superior temporal gyrus (STG) represents _______ speech sounds

slow varying

Semicircular canals are sensitive to

Head rotation

Otolith organs are sensitive to

gravity and tilt

Macula is oriented ______ in saccule

vertically

Macula is oriented __________ in utricle

horizontally

Semicircular canals detect

Angular acceleration

Vestibular nerve receive ____ released by ______ hair cells

Glutamate, depolarized

Pacinian corpuscle

Detects high frequency (speaker type shoot)

Meissner’s corpuscle

Detects lower frequencies

Sour substance ion channel pathway

H+ sneaks in and blocks K+ channels, causing buildup of positive charge and depolarization

GABA blockage

more wanting