neuro exam 2

afferent vs efferent

afferent = arrive

efferent = exit

thalamus function

primary sensory relay

cerebellum function

fine motor control, gait, balance, motor learning

basal ganglia function

important for control of voluntary movement

hippocampus function

critical for learning and memory

vision

properties of light

frequency/wavelength

intensity/amplitude

vision

what is light

energy; photon = segment of light energy

vision

cornea

clear, protective film covering pupil

refracts light to direct it into pupil

• prevents damage

• keeps in aqueous humor

vision

iris

colored, ring-shaped muscle

contracts and relaxes to adjust pupil size

• regulates how much light enters pupil by contracting

vision

pupil

space inside of iris

where light enters

vision

lens

clear, curved structure behind iris

adjusts shape to focus light onto retina

vision

retina

light-sensitive layer of tissue on inner surface of the eye (like camera film)

vision

photoreceptors

• where are they at in eye

• in retina

• rods: sensitive to low light

• cones: color vision and acuity (fine detail)

vision

bipolar cells

• where are they at in eye

transmit signals from photoreceptors to ganglion cells of optic nerve (CN II)

• in retina

vision

what is phototransduction

turning light into neural signals

vision

what happens after light rays enter eye (outer eye)

• bent by the curvature of the cornea and lens

• converge on photoreceptors in the retina

vision

rods

• where are they concentrated

• description

• in peripheral regions of retina

• sensitive to light and movement

• important for night/low light vision

vision

cones

• where are they concentrated

• description

concentrated in the central retina (fovea) where visual acuity is highest

• mediate color vision

• differential sensitivity to light wavelengths: red, green, and blue

vision

light passes through ___ and ___ before reaching ___

• except at…

through ganglion cells and bipolar cells before reaching photoreceptors

• except at fovea, which has highest density of cones

vision

photoreceptors respond to what in what order

light photons 1st

• bipolar cells 2nd

• ganglion cells last

vision

what modulates signaling between photoreceptors/bipolar cells and bipolar cells/ganglion cells

horizontal and amacrine cells

vision

are there more neurotransmitters in light or dark?

• why

in the dark = more NT

• because rods and cones depolarize at -35, so number of open voltage-gated Na and Ca2 channels is higher

vision

are there less neurotransmitters in light or dark?

in the light = less NT

• because when photons are absorbed by photoreceptors, the cell membrane becomes hyperpolarized to a minimum of -65 mV so number of open voltage-gated Na and Ca2 channels/NT release is reduced

vision

ganglion axons travel from ___ to…

from back of retina forward to join together in the optic nerve

vision

optic nerve axons exit the eye @…

exit @ the optic disc

visual pathways

monocular vs binocular field

monocular = seen by one eye (r eye sees r field)

binocular = seen by both eyes

visual pathways

visual field is focused by eye onto…

retinal field

visual pathways

left vs right retinal field

left retinal field = right visual field

right retinal field = left visual field

visual pathways

retinal ganglion cells from each eye travel along the __

the optic nerve

visual pathways

at the optic chiasm… what crosses over to connect with what and continues on what

• thus, all info from left visual hemifield will travel…

axons from nasal retinal hemifields cross over to connect with axons from temporal retinal hemifields from other eye and continue on optic tract

• thus, all info from left visual hemifield will travel on the right optic tract and vice versa

visual pathways

axons from optic tract will synapse in…

in the lateral geniculate nucleus of the thalamus

visual pathways

axons from the thalamus will travel via..

via optic radiations to the primary visual cortex (V1) in occipital lobe

visual pathways

information from the left visual hemifield is processed in the __ thalamus and occipital lobe

right

visual pathways

how is visual cortex organized

retinotopic organization

visual pathways

adjacent neurons in V1 process signals coming from ___ in retina

adjacent photoreceptors

visual pathways

there is a continuous topographic map of the visual field in the…

grey matter in the primary visual cortex

audiovisual speech perception

what brain area assists with phonemic processing

temporal visual speech area (TVSA)

light is perceived by ____ which connect with neurons that send signals through the… (5)

perceived by photoreceptors

send signals through the…

• optic nerves

• optic chiasm

• optic tracts

• thalamus

• primary visual cortex

what part of communication info is vision important for

• how

important for the INPUT of communication information

• gestures/McGurk effect (vision changes phonological perception)

visual info processing

visual field deficit = not getting sensation or perception?

not getting sensation

visual info processing

agnosia/neglect = not getting sensation or perception?

not getting perception

visual info processing

what is sensation

receptor activation and signal transduction to CNS

visual info processing

what is perception

interpretation of raw sensory inputs

visual info processing

what is the visual pathway

• retina

  • photoreceptors

  • bipolar cells

  • retinal ganglion cells

• optic nerve

• optic chiasm

• optic tract

• lateral geniculate nucleus of thalamus

• optic radiations

• primary visual cortex (V1)

what is the first neuron in the visual pathway?

bipolar cell

T/F:

all info received from the left eye is sent to the right thalamus

false

what type of white matter tract is the optic radiation?

projection

the primary visual cortex has ____ organization

retinotopic

what is the first place in the nervous system that processes sound from both ears?

superior olive

EEG measures electrical signaling corresponding to what aspect of neural signaling?

extracellular post-synaptic potentials

prosopagnosia is most associated with dysfunction in what visual pathway?

ventral stream

heschl’s gyrus displays ___ organization

tonotopic

T/F:

cochlear hair cells contain mechanically-gated potassium channels, which allow K+ to flow into the cell along concentration gradients while opened

true

according to how the superior temporal gyrus is organized, sounds with what in common would have the most overlap in neural activity?

manner of articulation

how is the primary somatosensory cortex organized?

somatotopically

what refers to the sense of position in the body?

proprioception

T/F:

EEG has finer spatial resolution than ECoG

False

what is the minimum number of neurons required for a reflex arc?

3

what part of the motor hierarchy contains cell bodies for upper motor neurons?

primary motor cortex (M1)

denervation atrophy and fasciculations on right side of tongue..

• what region of motor hierarchy is most likely to be the region impacted?

• what side is the lesion on

brainstem

right side lesion

which CN is the one that supplies most muscles of tongue

7: hypoglossal

if a lesion is in brainstem, that impacts what portion of movement most

motor execution

if the nerves that supply muscles of the larynx were damaged, which speech subsystem would be impacted most?

phonation

which stages of swallow are voluntary?

oral prep

oral transport

M1 is organized in what 2 ways?

somatotopically

by place of articulation

spastic dysarthria is related to dysfunction of..

motor execution

T/F:

speech characteristics of childhood apraxia of speech overlap with those of acquired apraxia of speech

true

T/F:

swallowing disorders will always have a neurogenic cause

false

damage to laryngeal motor control will impact which phase of swallowing the most?

pharyngeal

where is the swallowing central pattern generator located?

brainstem

T/F:

consequences of dysphagia are only related to getting nutrition and hydration and preventing pneumonia

false

T/F:

dysphagia can result from conditions only impact sensory systems and not motor systems

true

visual info processing

the primary visual cortex has ____ organization

retinotopic

visual info processing

visual signals are processed by cell populations within retina and then ___ to the cortex for more processing

project

visual info processing

what is a receptive field

region of sensory space on body where a stimulus will change the firing activity of a sensory neuron

visual info processing

what is feature detection

certain cortical neurons receive visual info and respond to only certain scene features

visual info processing

why does cortical visual processing need to use myelinated neurons

visual cortex must get relevant info from visual signal and elaborate/integrate info into a unified experience, must be very fast

visual info processing

what is parallel processing?

the brain’s capability to process visual components simultaneously (see face instead of separate eyes, nose, etc)

visual info processing

after primary visual cortex (V1), where does further visual processing happen?

V2, V3, V4, V5

visual info processing

dorsal stream

• towards what lobe

• what does it do

• __ pathway

• output is what

towards parietal lobe

analysis of visual motion - navigating space

where pathway

output: parietal cortex

visual info processing

ventral stream

• towards what lobe

• what does it do

• __ pathway

• output is what

towards temporal lobe

perception of visual world - recognizing objects

what pathway

output: hippocampus and anterior temporal lobes

visual info processing

agnosia: what is it?

• does problem happen before or after V1?

problem with perception/recognition

• problem is after V1

visual info processing

neglect: what is it

• does problem happen after or before V1?

problem with attention/awareness

• problem is after V1

visual info processing

visual field deficit: what is it

• problem is before or after V1?

loss of vision in certain part of visual field

problem getting to and within V1

visual info processing

agnosia affects what stream

ventral

visual info processing

neglect affects what stream

dorsal

visual info processing

visual agnosia is caused by a lesion to what

caused by a lesion to visual association cortex, sparing primary visual cortex

visual info processing

visual form agnosia vs associative visual agnosia

visual form: cannot recognize, copy, match, or discriminate simple visual stimuli

associative visual agnosia: can draw copy but not identify what it is, may identify if holding object

visual info processing

prosopagnosia

face blindness - inability to recognize familiar faces, including own face

visual info processing

prosopagnosia associated with damage to dysfunction in (3)

lingual gyrus

parahippocampal gyrus

fusiform gyrus

visual info processing

spatial neglect

• associated with damage where?

deficit in attention to one side of space

associated with damage to the attention networks (often R hemi stroke)

imaging

spatial resolution: low vs. high

low: can see overall brain structure, not single neurons

high: can see single neurons or small groups of neurons in specific brain areas

do techniques that measure the entire brain have low or high spatial resolution?

low spatial resolution

is there a correlation between spatial and temporal resolution?

no

imaging

temporal resolution: low vs. high

low: we can only get snapshot of brain processes every few seconds, minutes, or hrs

high: we can see changes that are ms apart (like in an AP)

imaging

are pre- or post-synaptic currents measurable from surface of skull

post-synaptic are measurable from surface

imaging

how does EEG measure neural activity

measures voltage changes from millions of neurons at scalp using metal discs or cup electrodes

• electrodes need direct connection to skin

EEGs measure voltage changes arising from _____ from neurons near the scalp

post-synaptic potentials

could you measure signaling from hippocampus with EEG?

no, hippocampus is too ventral/too deep

imaging

people with hearing loss have ____ visual-evoked potentials

• why

higher

they rely more on visual information