REACH-DL | Muscle 3: Electrooculogram (EOG)

EOG Cable Setup

Plug the red, black, and green electrodes into the REACH.
Use an alcohol swab to clean and scrub the areas where the electrodes will be placed and let the areas dry before attaching the electrodes.

Snap the recording leads onto the sticky electrodes before putting them on:

The red lead is on the electrode next to the right eye just to the right of the eyebrow.
The black lead is on the electrode next to the left eye just to the left of the eyebrow.
The green lead is on the electrode below the right ear.

Drape the leads for the electrodes over your shoulder. There should be no tension on the electrodes.
Sit quietly with your hands in your lap where possible.

Note – For all these experiments it is important to observe your physical eye movements. Have a mirror available so you can see yourself while doing these experiments. Watch the way your eyes move.

This observation of yourself can be done after you have collected the data. Just look in a mirror while you do the activity but are not recording any longer.

THIS LAB IS ALL OBSERVATIONAL – there are no mathematical measurements.

Saccades

Aim

To demonstrate the type of electrical activity that occurs in the muscles as you are reading.

Procedure

Open the Journal by clicking on the Notebook icon. You will see a list of 4 lines of 5 letter words and a simple paragraph.
Avoid any voluntary movements of your head or body during the recording. Only your eyes should be moving while your are reading. Do NOT move your head.
Type "Saccades -Slow" in the Mark box.
Click Record and wait 10 seconds for the recording to reach baseline.
Focus on the first word on the list. Begin reading VERY SLOWLY as you click on the Mark button.

Try focusing on each word for about 3-4 seconds before moving on to the next word.

After the first cyclic pattern in completed, click on the AutoScale button. Observe your eyes as you are reading SLOWLY.
Click Stop when you have finished reading ALL 4 lines of words.
Click File ---> Save As, name the file "EOG", and save your data to your LabScribe Data folder on your Desktop.
Type "Saccades-Normal" in the Mark box.
Click Record and wait 10 seconds for the recording to reach baseline.
Now read the paragraph at a NORMAL speed (not too fast or too slow). Try to focus on each word for about 1 second.
When you are done with the paragraph, click Stop and save your data.

VOR

Aim

To demonstrate the type of electrical activity that occurs in the muscles as you remain focused on an image or word on a page while rotating your head from side to side.

Note: Be sure to observe your eye movements as well as the pattern of the recording. This can be done after you are collecting data and just look in a mirror while you do the activity.

Procedure

Select an image on which you can focus as you rotate your head from side to side. There should be a single image on a piece of paper.
Avoid any voluntary movements of your body during the recording. Only the your head should be moving while you are focusing on the target. Do NOT move your eyes – only your head will be moving.

Hold the paper steady at eye level.

Type "VOR" in the Mark box.
Click Record and wait 10 seconds for the recording to reach baseline.
As you focus on the image and begin to move your head side to side, click Record. Click on the Mark button. Record this for 15 seconds.
After this first cyclic EOG pattern in completed, click on the AutoScale button. Observe your eyes as you rotate your head.
Click Stop when you have finished the exercise.
Select Save in the File menu.
Type "Atypical VOR" in the Mark box.
Repeat Steps 4 through 6 while you either increase or decrease the speed of head rotation. Make a note of what you have chosen, or try both, slow first and then fast (15 seconds each).
Click Save and save your data.

Pursuit

Aim

To demonstrate the type of electrical activity that occurs in the muscles as you follow a moving target.

Note: Be sure to observe your eye movements as well as the pattern of the recording. This can be done after you are collecting data and just look in a mirror while you do the activity.

Procedure

Suspend a target, like a tennis ball, on a string. Set the length of the string at about 3 feet (you may have to stand on a chair). You should be able to swing the target from side to side like a pendulum.

Only the your eyes should be moving while you are following the target. Your head will remain stationary.

Type "Pursuit" in the Mark box.
Click Record and wait 10 seconds for the recording to reach baseline.
Click the Mark button. Get into a good position to follow the target.
Swing the target like a pendulum. You should be focused on the target and follow it with your eyes.
Try to observe your eyes as you are following the target.
Click Stop to halt recording when the target has completed 10 oscillations.
Click Save.
Shorten the string used suspend the target by about 1 foot, so the target will swing faster.
Type "Fast Pursuit" in the Mark box.
Repeat Steps 3 through 6 while the target swings slowly.
Click Save.

Answer the following:

Exercise 1

How does the pattern of the EOG recorded during the "slow" reading of the paragraph compare to the "normal" reading of the same paragraph?
How does the movement of your eyes differ between these readings?

Exercise 2

How does the pattern of the EOG recorded while you are rotating your head normally compare to the pattern during the period when the rotation of the head is at a different speed?
Describe the motion of your eyes during VOR. Is it smooth or saccadic?
Does the motion of your eyes differ between VORs of different speeds?

Exercise 3

How does the pattern of the EOG recorded while you are is pursuing a fast moving target compare to the pattern during the pursuit of the slower moving target?
Describe the motion of your eyes during pursuit. Is it smooth or saccadic?
How does the motion of your eyes differ between pursuits of different speeds?