Neuro 48 Visual Motor System

Front 1

so the VOR is it reflexive or voluntary, what are the voluntary movemnts

Back 1

VOR is reflex

VOLUNTARY
1. Saccades: fast, look at stationary
2. Smooth Persuit: slower, look at moving
3. Vergence: disconjugate movemnts

Front 2

WHAT is a disconjugate voluntary eye movemnt? waht about congujate

Back 2

Discionj: vergence. adjest to near/far objects

Conj:
saccades: look at stationary target, fast
smooth persuit: follow moving target, slow

Front 3

what system controls voluntary eye movements

Back 3

visual motor system

Front 4

waht is internuclear opthalmoplegia

Back 4

interruption of MLF

medial rectus is impaired so we loose adduction

can be BL or UL

Front 5

what is hte term that describes the loss of adduciton due to desctuction of hte MLF nad loss of medial rectus control

Back 5

internuclear opthalamoplegia

Front 6

is internuclear opthalmoplegia BL or UL

Back 6

can be either

**its interruption of ascending MLF so medial rectus control is lost so we cant do adduction

Front 7

what CN and what mm raises the eyelid

Back 7

CN 3
levator palpebrae superioris

Front 8

what does hte levator palpebrea superioris do? what cn

Back 8

Cn 3
raises upper eyelid

Front 9

are the lower eye lids innervated with certain mm to open/close

Back 9

nope. they rely on gravity

Front 10

what Cn and what mm closes the eyelid

Back 10

CN VII
obicularis oculi

Front 11

what does hte obicularis occuli do? what cn

Back 11

CN 7
closes eyelid

Front 12

what mm and Cn is respinsible for closing the eye? what about opening

Back 12

close: obicularis oculi, CN 7
open: levator palpebrae superioris, CN 3

Front 13

so what is the helper for levator palpebrae superiors (CN 3)

Back 13

the superior tarsal mm
SNS innervation

**both OPEN the lid

Front 14

waht is the SNS innervation to open the eyelid

Back 14

supeiror tarsal mm

**aids CN 3 and levator palpebrae supeioris

Front 15

what is horners syndrome

Back 15

miosis (eyes constrict, PNS)
Ptosis (upper lid sags, SNS superior tarsal mm. levator is still good)
anhydrosis: dry eyes

Front 16

what sthe cute thing to remember the occular mm and theur innervation

Back 16

LR6 SO4 OA3

Front 17

lesion of what N gives down and out? what mm are involved

Back 17

3

LR "out"
SO "down"

Front 18

what does the superior oblique do? inferior

Back 18

Supeiror: depression, abduction

Inferior: elevation and ABduction

Front 19

what will the eyes do when CN 3 is damaged

Back 19

down and out

LR and SO

Front 20

what are the intraocular mm and what is thier innervation

Back 20

PNS
sphincter pupillae
ciliary

SNS:
dilator pupilae

Front 21

so the PNS innervates the ciliary mm nad sphincter pupillea, what is the ganglion?

SNS does dialtor pupilea, what gang

Back 21

ciliary

superior cervial gang

Front 22

what happnes when ciliary gang causes PNS to contract hte ciliary body

Back 22

the ligaments are less tense and the intrisic elasticity in the lens causes it to ball up and become more spherical

Front 23

for near vision wht do we want the lens to do? how is this accomplished

Back 23

want it to fatten up into a ball

**done be activating PNS (ciliary) and the ciliary mm

Front 24

what structures of hte brainstem are importnat in visual motor system (caudal to rastral)

Back 24

vestibular nuclei
MLF
abducens (and interneurons)
trochelar nucleus
occulomotor complex
edinger westphal
pretectal
interstitial nucleus of cajol

Front 25

so in the visual motor system info goes to the vestibular nuclei, adn then where?

Back 25

to the abducens nucleus

**it can either leave via abducens motorneurons
OR8
*conect with abducens internuclear neurons to get to the CL oculomotor nucleua

Front 26

so the visualr motor path goes from vestibular nuclei, to abducens and will either leave as the abducens N OR go to CL oculomotor nucleus, whre does it go from here

Back 26

trochlear nucleus

**can then leave as troclear N to supply the Superior Oblique

LR4 SO4 AO3

Front 27

where is the edinger westphal nucleus, what does it do

Back 27

in the midbran/diecephalon secteion

its the light white triangle locaterd posterior

**its PNS to sphincter pupillea and ciliary

Front 28

what type of voluntary eye movemnt has a burst tonic fire rate

Back 28

saccades

**FAST, look at stationary movements

Front 29

is saccades cong or discong

Back 29

cong

FAST, look from 1 atationary pbject to the next

Front 30

what is the interstitial nucleus of cajol, is this the only nucleus that does this fx

Back 30

it controls VERTICAL saccades (located near CN 3 nucleus)

**the rostral interstitial nucleus of the MLF also does this (no need to ID)

Front 31

what is the characteristic fire of saccades?

Back 31

burst tonic

**fast
**stationary obbects
*vertical: CAJAL (and rostral interstitial nucleus of MLF)
*Horizontal: PRRF (aka HGC)

Front 32

wht are the vertial and horizontal gaze centers for saccades

Back 32

Vertical: cajal and rostral interstitial nucleus of MLF

Horizontal: Paramedian Pontine Reticular Formation (PRRF) also called horizontal gaze center

Front 33

waht isthe PRRF

Back 33

paramedian pontine reticual formation

Horizontal Gaze Control

This is for saccades, fast, cong, stationary objects, burst tonic

Front 34

where is cajol and PRRF on myelin stain

Back 34

Cajal: Vertical, Midbrain, superior to red nucleus

PRRF: Horizontal,

Front 35

where is the horizontal gaze center?

Back 35

in the pons in the little area ant to the cerebral aquaduct

PRRF

Front 36

where are the horizontal and vertical gaze centers for asaccades movement

Back 36

Vertical: midbrain, above red nucleus (cajal and the rostral MLF)

Horizontal: in the pons, PRRF, near the crebral aquaduct just ant to it. (ROSTRAL pons, can see trigeminal motor and sesnory, NO abducens here)

Front 37

at what level of the pons is the horizontal gaze center? is this a single structure or a collection of structures

Back 37

Rostral: trigeminal sesnory and motor are here, NO abducens

its a collection of structures

Front 38

what are the 4 cell types involved with the horizontal gaze center of saccades

Back 38

horizontal gaze: PPRF

1. Omnipause: inhibitory cells that are turned off during sassades

2. BURST: excitatory burst neuron

3. TONIC: tonic excitation, prerositus hypoglossal Nucleus

4. Inhibitory cells: inhibitory Burst neurons. inhibit the antagonistic mm

Front 39

what isthe big clamp that shuts off the horizontal gaze center

Back 39

omnipause cells

**these are inhibitroy but during saccaddes its turneed off to allow excitation

Front 40

what cells do tonic excitation in the horizontal saccades path

Back 40

tonic (step) cells

**prepositus hypoglossal

Front 41

what are omnipause cells

Back 41

they are in the horizontal gaze center (PPRF)

these cells are inhibitory and are turned OFF in order to initiate a saccades

Front 42

what cells are responsible for the characteristic burst tonic AP in saccades (horizontal)

Back 42

Burst:Excitatory Burst neurons, this is the burst of excitation

Tonic: prepositus hypoglossal nucleus, tonic excitation

Front 43

how are antagonistic mm inhibited with horizontal saccades

Back 43

inhibitory burst neurons

Front 44

what happnes when an opniponce cell is turned off

Back 44

the burst cells and the inhibitory burst neurons are active

**this allows the eyes to look in the same direction as the activated HGC, and the antagonist mm are now inhibited

Front 45

so whats the whole process for the sacceds process using HGC (voluntaryli look R)

Back 45

1. omnipauce cells are turned off via L frontal eye field

2. this acts to activate the Burst cells and hte inhibitory Burst cells. burst cells then priject to R abducens nucleus to activat ehte R lateral rectus, it also crosses midline to act on the L oculomotor complex. and move the L medial rectus. (eyes move R).

3. lastly the tonic cells are activated to keep the eye looking R

Front 46

when is hte opnipause active? what does this aloow? what happens when its inactive

Back 46

the opnipase is INHIBIROTY so its active when the eyes arent moving

it is inactive to allow the eyes to move horizontally to look at stationary objects. this frees the burst and the inhibitory burst so the mm can be activated nad the antagonists can be inhibited

Front 47

from the R abducens what happens/

Back 47

1 motor neuron goes to IL (R) Lateral Rectus

1 internuclear neuron goes to CL (L) oculomotor nucleus to activate the L medial rectus

**ta da, the eyes move R. recall there must have been an input to the L frontal cortex area to turn off the omnipause area and activate the R HGC (rostral pons)

Front 48

so if the R abducens is stim whats going on with the L abducens in saccades

Back 48

its being inhibited by inhibitory burst cells (activates the same time the burst cells are activates)

this INHIBITS the antagonists

Front 49

ok so how do we voluntarily get the eyes moving R. what happens in the cortex

Back 49

the L cortex turns off the omnipause cells

**the areas are
L frontal (8)
Supplementary (6)
Parietal (7)

Front 50

what are the cortex areas accosiated with voluntary eye movement (broadman numbers)

activation of the R cortex does what

Back 50

frontal 8
supplementary 6
parietal 7

when the R cortex is activated the L HGC is active and the eyes move L via an active L abducens

Front 51

so how does the supeiror coliculus create sys movement

Back 51

its a reflex (mix of reflex and voluntary, the sup colliculus responds to sensory input)

**the sup colliculus will cause the eyes to move to the CL direction

**the middle and intermediate supioer colliculis generate saddaces

Front 52

how does the frontal cortical motor eye field (8) (also supplementary 6, and parietal 7) make the eyes move

Back 52

voluntary saccades

The cortex makes the eyes look in the CL direction

Front 53

what part of sup colliculus induces saccahades, to wht side

Back 53

middle, intermediate

**the eyes move CL to the side that the sup colliculus is activated on

Front 54

does the sup colliculus project directly to the abducens or does it use HGC

Back 54

HGC

Front 55

so the L cortex makes the eyes move R using the HGC, how does VOR make hte eyes move R

Back 55

rotatio of the head to the left

**this makes endo move R and dopolarizes the L hair cells. this activates the L vestibular nuclei which activates hte R abducens (from here its the same)

**the VOR doesn NOT usethe HGC

REFLEX, not voluntary as in the cortex (frontal 8, supplementary 7, parietal 7)

Front 56

does the VOR inhibit the antagonists?

Back 56

?????

Front 57

what is the tecto bulbo spinal tract

Back 57

fibers from the superior colliculus go here and help oriente teh UE and head
**recall the sup colluculus makes sacchades in a "reflex" to a sensory input

Front 58

what path goes directly to abducenst

Back 58

VOR, reflex, bypasses the HCG (PPRF)

Front 59

what things will cause the eyes to look CL

what about IL

Back 59

vestibular nuclei
frontal, supplementary, parietal cortex
supeiror colliculus

Eyes move IL to the...
Abducence
HGC

Front 60

what are some ways we can get a reflex to make the eyes look

Back 60

superior colliculus
VOR (turn head and activate vestibular nuclei)

Front 61

the abducence nucleus receives DIRECT info from what

Back 61

CL vestibular nuclei for VOR

Front 62

what paths project to the PRRF, HCG,

Back 62

sup colliculus
frontal motor

THey both project to the CL HCG, activation of the L sup colliculus or frontal cortex (8) causes hte eyes to move R

Front 63

when the PPRF makes the eyes move do they move IL or CL to the active HCG

Back 63

IL

Front 64

what is the path of pursiut movments

Back 64

recall this is a VOLUNTARY (slow) movement where you track a MOVEING object, we need some sort of visual input

1. Eyes (retina) project to LGN and 1 visual cortex

2. Visual cortex to teh assocaition centers, Frontal (8), supplementary (6), and parietal (7)

3. from cortex to the pontine nuclei

4. Pontine nuclei to floculonodular lobe of cerebellum

5. leave cerebellum via juxtarestiform body and enter the vestibular nuclei

6 from here they go to abducens and occulomotor nuclei to get the eyes to move

Front 65

how does info end up at the vestibular nuclei for pursuit movements

Back 65

1. starts in eyes, goes to LGN and 1 visueal cortex

3. from visual cortex it goes to association areas: frontal (8), supplementary (6), and parietal (7)

4. then it descends to pontine nuclei

5. from pontine to flocculonodular lobe of cerebellum

6. leaves cerebellum via juxtarestiform and enters the vestibular nuclei

from this point its the same as all others it goes to abducens and occulmotor

Front 66

verggence movemnets are associated with what? w

Back 66

accomidation

1. eyes converge (sidcong of eyes, BL medial rectus activation)

2. Ciliary body contracts and lens becomes round

3. pupillary sphincter activates (pupils constrict)

*8the last two are PNS, ciliary gang

Front 67

what part of the bran controls the disconjugate mevements seen in vergence? what does it do

Back 67

midbrain supraocculomotor area

**BL projections to CN 3 for BL activation of medial rectus

(can also be BL to abducene to release from the convergence)

Front 68

what can stim the Abducens or occulomotor BL

Back 68

midbrain supraocularmotor area

**convergence, dysconjugate movements

Front 69

what does hte midbrain supraoculomotor area do/.

Back 69

activates abducens or occulomotor BL for convergence and divergence




**dynconjugate mvmnts seen in accomidation

Front 70

what is the accomidation triad

Back 70

1. eyes converge
2. pupil constricts (sphincter pupilea)
3. lens fattens up (ciliary)