Vision and Neuroscience

For a cool experiment, follow the instructions on the next page!

If you see this icon, it means that there is a link to interactive activity.

This is Neuroscience Nancy. A neuroscientist is someone who studies the brain. She is a special neuroscientist that studies vision, or how we see. She will be sharing facts about the eye.

For more hands-on learning activities, and other resources please see the end of the book.

Now, let's see what we can learn....

People who cannot see one or more colors are considered colorblind. They missing something called photopigments in their cone cells.

There are three main types of colorblindness. Below are examples of three types:

Click <a href="https://www.youtube.com/watch?v=7KrakjEHeYs">here</a> for a video on colorblindness.

The anatomy (or parts of our eye), work together to help us to see. Photoreceptors in our eyes see color and dim light. Our occipital lobe processes what we see. Our brain tries to make sense of what it sees, but sometimes it doesn't get is exactly correct and we get optical illusions.

Click on this <a href="https://www.youtube.com/watch?v=i3_n3Ibfn1c">link</a><a href="https://www.youtube.com/watch?v=syaQgmxb5i0"> </a>for a quick video to review how the anatomy of the eye assists us in seeing!

1. Stare at the page on the right. 2. Cover your left eye. 3. Stare at the plus sign. 4. Slowly move the screen, towards you while staring at the plus sign. (Or, slowly walk closer to the screen). 5. At some point the dot will disappear. This is your blind spot!

Here is another optical illusion. How many legs does this elephant have?

Images are flipped upside down when they hit the retina and then flipped right side up on it's journey to brain.

Behind the pupil is the lens, a clear part of the eye that bends, or refracts, the incoming light to produce a focused image onto the retina.&nbsp;

Click <a href="https://www.youtube.com/watch?v=8uAy_G4RPPE">here</a> to find out why images are reflected upside down on your retina.

The iris is the colored part of the eye. It is a muscle that changes the size of the pupil. The size of the pupil allows different amounts of light to enter the eye.&nbsp;

The iris relaxes and closes the pupil in bright light.

The iris contracts opening the pupil in dim light.

Why do some people have different color eyes?

Eye color is due to different pigmentation, or coloring in the iris. The color of a person's eyes is based on genes.

This question will be answered as we explore the following...

* The parts of eye, and how each piece helps us see. * The special cells in our eyes that relay color and dim light to our brain. * The area in our brain where what we see is processed. * How sometimes what we see can be misleading.

Our field of vision has a small blind spot. You probably never noticed it. Our blind spot is where the optic nerve passes through the retina. We usually don't notice it is there because our brains use information from other areas in our field of vision to fill in our blind spot.

Information from your eyes travels to your brain. Your brain then turns this message into something you recognize.

Similar to how a car travels on a road, signals travel to the brain from the eye, relaying messages.

The brain is divided into four lobes. The part of the brain that processes vision is called the occipital lobe, which is located on the back of the brain! It is here that the visual messages are translated.

Light must first pass through the cornea, a clear, thick, dome-shaped surface that covers the front of the eye. The cornea also protects the eye from injury.

The Science Behind the Eye

Center for Excellence in the Neurosciences University of New England

* For more information on how the eye works, click <a href="https://dana.org/article/the-senses-vision/">here</a>.

* Information on eye movements and eye disorders, click <a href="https://dana.org/article/the-eyes-are-windows-into-the-brain/">here</a>.

* Extra information discussing vision, click <a href="https://dana.org/wp-content/uploads/2019/05/fact-sheet-senses-vision-baw-2020.pdf">here</a>.

* 'The Dress' activity, click <a href="https://michaelbach.de/ot/col-dress/index.html">here</a>.

* Optic experiments at home, click <a href="https://www.optics4kids.org/classroom-activities/5-10">here</a>.

* 13 <a href="https://www.treehugger.com/optical-illusions-will-blow-your-mind-4864290">More optical illusions</a>

Works Cited 1. https://webvision.med.utah.edu/ 2. https://dana.org/article/the-senses-vision/

This optical illusion is called the impossible cube.

The brain tries to make sense of what it sees, but sometimes the brain interprets what it sees incorrectly. Images that challenge or deceive the eye are called an optical illusions.

Both answers are correct. The image you see may even switch back and forth from being a duck and a rabbit depending on how you look at the picture, or  your perspective.

The brain tries to make sense of the world by organizing what it sees into something familiar or meaningful.&nbsp;

Check out this <a href="https://www.youtube.com/watch?v=VYIr40D7wNw">video</a> for more optical illusions and the science behind them.

They help you see, of course! But have you ever wondered how your eyes help you to see?

Your eyes are one of your five senses. Senses are something that you understand the world around you.

The brain helps us understand what we see

After photoreceptors translate light, color, and shapes into signals, these signals travel through the optic nerve and to the brain. It is in the brain where are the signals are pieced together into meaningful images— people, places, or things that we recognize.

A photoreceptor cell is a special type of cell found in the retina that is capable of converting light energy into electrical signals. There are 2 types of photoreceptors:

RODS: Make vision possible in low light.

CONES: Most sensitive to one of three different colors (green, red, or blue).

Eye fact: There are more rods than cones in the human retina.

The retina is a thin tissue on the back of the eye. The tissue contains the special cells called photoreceptors that convert light into electrical signals.

These signals are carried to the brain by the optic nerve. The optic nerve enters the the center of the retina in the back of the eye.

The image above is a human retina imaged through an ophthalmoscope.

Now let's do some illusions with color!

Click <a href="https://www.youtube.com/watch?v=gjesfzWozo4">here</a> to try the Stroop Test.

The Stroop test is difficult because your brain is getting two pieces of information at once: your brain is trying to read the word and trying to process the color is sees. 

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