Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bio 373L > Lab 3: Oculomotor Muscle Control > Flashcards

Lab 3: Oculomotor Muscle Control Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the objective

A

-measure and investigate the activity of medial and lateral rectus muscles during eye movement (saccades, pursuit, vestibular ocular reflex and vergence)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

how many muscles does the human eye have attached to its exterior surface and how are the grouped

A

6

into 3 groups(antagonistic pairs) that control horizontal, vertical and torsional movement/position of eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the names of the muscles that move the eyes along the VERTICAL axis

A

-medial rectus muscle (move towards nose… ADDUCTS)
-lateral rectus muscle (turns away from nose… ABDUCTS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the names of the muscles that move the eyes along the HORIZAONTAL axis

A

-superior rectus muscle (turns up… elevates, with slight rotation towards nose… intorts)
-inferior rectus muscle(turns down…depresses, with slight rotation away from nose… extorts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the names of the muscles that move the eyes along the TORSIONAL axis

A

-superior oblique muscle(rotates top of eye towards the nose (intorts) with slight depression
-inferior oblique muscles(rotates away from nose… extors with slight elevation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DO eyes have a tonic component or a phasic component

A

BOTH: innervafted by motor neurons that have electrical activity

-tonic component: control position of eye
-phasic component: control velocity of the eye movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

is the relationship between eye position commands and firing frequency of the motor neuron linear

A

YEP! So is the relationship between eye velocity commands and firing frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the path of eye velocity commands

A

direct path
-from specialized brain formations to the motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the path of eye position commands

A

-product of integration of eye velocity commands sent along an indirect path to a neural integrator(network of neurons function as this)
-the output of the neural integrator provides the eye position commands to motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 5 types of eye movements

A

1) Saccades
2) Pursuit
3)Vestibular Ocular Reflex
4) Vergence
5) Optokinetic reflex

for this test we will look at the four because thjey have usinque electrical change activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In this experiment the subect will perform tasks that will generate electrical activity that willa lter the stnading voltage between the front and back of the eye that is correlated withhorizontal eye movement true or false

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the record of electrical activity called for eye movement

A

electrooculogram ECG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is saccadic movement (saccades)

A

-what we use to read
-these movements rotate both eyes so that image of interest falls on the FOVEA (fovea centralis(focal point): region of retina that sees in detail
-movements are quick (v=as high as 800 degrees of movement/second) to make uo for poor vision that occurs during it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the fovea centralis

A

focal point
-region of the retina that sees in detail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

HOw are sacadic movements accurate

A

-system uses an internal estimate of eye potision from its neural integrator to guide and stop the saccades

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is pursuit

A

-when the eyes follow a moving object like a ball
THEORY: movement keeps fovea pointed at the moving target

-initial delay (latency) is present
-this delay appears as a saccadic movement that help the eye cathc up and then it turns to pursuit once it starts to follow the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is there an initial delay in pursuit movement

A

-because the signal from the eye that indivated that the ball is movement hs be to conducted through the many synapses of the brain

essentially by the time the eye percieves that the ball is moving and recognizes it, and determines that it needs the eye to continue following it, it makes a delauy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is vestibular ocular reflex (VOR)

A

-reflex keeps image locked (stationary) on retina as the head moves
-it is a phasic movement
-simple central reflex arc that involes threeneurons ONLY

How does it work?

1.semicircular canalds of ear detect head movement velocity
2.this info then goes through afferent nerve and interneuron
3. then to the motor neurons of oculomotor muscles
4. oculomotor muscles now will rotate at the VELOCITY OF HEAD MOVEMENT (it matches it)_ so the image stays on the RETINA

Eyes held on throuhg tonic response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is VOR faster than pursuit

A

because it si a simpole neural reflex arc that only involves three neurons

19
Q

if the velocity of eye movement doesnt match the velocity of head movement, would VOR work

A

NO

similarily, if the semicircular canalds of the ear did not get the correcr velocirty of the head , it also would not work

20
Q

If eyes did not jave tje tonic response neural circuit what would happen

A

-eyes are hekd on the image throuhgha. tonic response along a indirect path through a revertabrating neural circuit between afferent and motor neurons
-it is a short term memoruy device that prevents the eyes from drifting away as the head moves

21
Q

What is vergence movement

A

-moves fovea of each eye to an object close to far (diverge), or far to close (converge)
-PREVENTS DOUBLE EYE VISION

22
Q

Whas the difference between the eye movement in vergence and in saccades

A

vergence: eyes move inopposite direction

saccades: eyes move in same direction

23
Q

Convergence vs divergence

A

Converge: movbe from far to close

diverge: move from close to far

24
Q

Optokinetic reflex

A

-think when a large object is moving in front of you (has to take up a large portion of your retinaie field of vision) is moving, it seems as though you are noving too but in opposite diredction

textbook definition: is active when the ful field of vision has moved across a large portion of the retina

-similar to VOR but is better for slow, prolonged movements since it works slower

25
Q

What is the test for optokinetic reflex

A

-use a deive called the optokinetic drum, which projects a series of rotating images on the wall of a small circular room while the subject is seated in middle of room

26
Q

Equipment required

A

-PC Laptop
Black iWorkx case containing:
_IXTA ROAM data acquisition unit with power supply and usb cable
-iWire-B3G harness
-red green and black electrode lead wires
-Disposable EMG electrodes
-Ball with 5ft string

27
Q

IXTA ROAM SETUP

A

Follow initial steps…

then…

1)Connect the red green and black elecrodes to the wires on the iWire-B3G
2)Place electrodes as such:
black: beside right eye
green: on neck of right side under ear
Red: beside eye on left side

3)have the subject sit down

28
Q

what do each pf th4 electrodes mean

A

red (+1)
black(-1)
green(fgrounding)

29
Q

Software setup

A

1) Click labscribe
2)click settings, human muscle folder, and EOG-iWireB3G file

30
Q

What is the procedure for saccades

A

1) Select a 10 line + paragraph for subject to read
Note: # of words in each line, length of line and formating of paragraph matters for the shape of EOG
2)Instruct subject not to move head or body during reading
3) Type subject name into markbox and write saccades
4) INstruct subject to foxus on the first word, click record, click mark button as they start reading
5) Click stop when done
6) Save as Saccades

Part 2:
7) instruct to read same paragraph slowly
8) type Slow saccades into markup box and start recording when they focus and cock start when hit
9)SAve as Slow Saccades

Part 3:
10) Type New Paragraph into markup box
11)Have subject read something witha more complex format (multiple columns or more words per line)

31
Q

How does the pattern of EOG recorded during the “slow saccadic” reading of the 1st para compare to the normal readning of rht same paragraph? How does the motion of the eyes different between these readings

A

-pattern is different bc

:length of saccades is longer for the slow saccadic since they can be fixated on words too
the motion of the eyes was less for these as well

32
Q

How does the pattern of EOF recorded during the first paragraph of saccades differe from the pattern o0f the more complicated paragraoph

A

-increase in saccadic activity per unit time, potentials had more jumps and drops, which indicates that there was an increase in the frequency of the signals being fired to the efferent neurons of the medial and lateral rectus muscles, in order to expand the range of motion, as the individual is not just reading from left to right

this is why there is an increase in saccadic activity because need more AP sent to the eyes to have irreguar movement

33
Q

Vestibular Ocular Reflex Procedure:

A

1) choose a word for the subject to focus on
2)subject should nt move head involunatry, should just rotate
3)type name VOR into markup box
4)click record while staring at the words and rotating,
5) click stop once done

Part 2:
6) type Atypical VOR into markup box
7) Have subject rotate head at different speeds or different degrees
8) repeat

34
Q

How does the pattern of EOG recorded while the subject rotates slowly comprare to pattern when the rotation is to different angle or speed

A

The pattern in general for this reflex is a smooth sin wave: this is because the muscles engaged for both eyes is the same but oppsite (ie when right, muscle 1 activated in right but mscle 2 in left, but when u turn left it flips),

since they are in the same degree and speed, it is innervating the muscles with an AP that is equal but opposite in direction, leading to the sin wave

Different speed causes a difference in the length of a wave cycle (not the amplitude)

Different degrees causes a difference in the amplitude of the sin wave as a larger degree of rotation meant more neurons were innervated for a wider range of movement of the muscle, leading to more electrical activity (so higher amplitude for the wave and magnitude that is swithced)

35
Q

Describe the motion of the subjects eyes during VOR. Is it saccadic or smooth

A

It is smooth since the

36
Q

Does the motion of the subjects eyes differ between VORs of different degrees and velocities

A

the motion of the subject eyes does differ as the velocity of the vestibular ocular reflex changes it causes the velocity of the eyes to increase as well

ie moving the head at a different speed will cause the eyes to move at a different speed too

37
Q

Pursuit procedure

A
  1. suspend a ball to string, set it to 3 ft, make sure u can suspend it like a pendulum
  2. Name pursuit into markup
  3. swing the ball like a pemdulum and ave the subject follow it with their eyes
  4. click mark when they drop ball from top
  5. Stop it

Part2:
6. lengthen the string by a foot or more
7. type slow p[ursuit
8. do the same

38
Q

How does the pattern of the EOG recorded while the subjecg is pursuing a fast moving tagrget compare to a slower moving target

A

-smooth sin again because of reciprocal activation of medial and lateral rectus muscles

As the eye’s velocity, similar to the vestibular ocular reflex, matches, for the most part, the velocity of the ball, any decrease in the oscillating ball’s velocity will mean a decrease in the eye’s velocity and a decrease in the degree at which the eyes must move to, as the eyes are following the ball

therefore a faster ball had a decreased amplitude since the degree which it swung at was less so less neurons need to be innervated to move the eye

NOTE: amplitude decreased as time increased since the degree at which the ball swings decreases as it swings

39
Q

Describe the motion of the subjects eyes during pursuit. Is it smooth or saccadic

A

SMooth, following an object that is moving produces a smooth eye movement

but saccadic at the start or when the ball switches directions as therenis a lag

The eye’s movement is saccadic at the start of the exercise, and at points where the ball was switching directions (seen at the maximum) as the eye has a delay in matching the initial velocity of the ball at the start, and the switch in direction

40
Q

How does the motion of the subjects eyes differ between pursuits of different velocities

A

eyes move to shorter degrees

the faster it is, the shorter the degrees of motion so the less the muscles need to be innervated

41
Q

Vergence Procedure

A
  1. Find two targets similar sized and place them 2-3ft apart, with one being infront
  2. Subject st look at the far one for 4 seconds then the close and alternarte
  3. when the subject loks from far to close type C when close to far type D
  4. do it 10 times
    5.do it slowly after
42
Q

how does the pattern for convergence differ frm the pattern for divergence

A

Convergene:an increase in electrical activity The reason for this increase in electrical activity is due to the contraction of the medial and lateral rectus muscles to bring the eyes in to focus on a near object

Divergence: decrease in Electrical activity (high chunk to low chunk)
-it is a drop because it is the relaxation of the muscles thatwere contracted for convergence (since resting is at far)

43
Q

how doe the pattern for the quick movements between targets different from slow

A

slower movement between the targets increases the saccadic activity between the maximum and minimum potentials as it increases the ability of the eyes to focus on objects between the distance and near the target

usually not much sacadic activity present in the eof

44
Q

describe the motion of the subjects eyes while foccusing from one to the other

A

the motion of the eyes was not smooth, it was saccadic/ jumpy

45
Q

How does the motion of thesubjects eyes differ between quick and slow vergences

A

quick causes an increase in potentials so more movement

Bio 373L (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions