2-Minute Neuroscience: Optic Nerve (Cranial Nerve II)

The optic nerve, also known as the second cranial nerve, is responsible for transmitting visual information from the retina to the brain. In this video, I discuss the anatomy and function of the optic nerve, as well as describe what can happen when the nerve is damaged.

TRANSCRIPT:

Welcome to 2-minute neuroscience, where I explain neuroscience topics in 2 minutes or less. In this installment I will discuss the optic nerve.

The optic nerve is a sensory nerve responsible for transmitting information about vision to the brain. The nerve begins in the retina as the axons of cells called retinal ganglion cells. These axons come together to leave the eye at a region called the optic disc and form the optic nerve.

The optic nerve leaves the eye and extends to a structure called the optic chiasm where it meets the optic nerve from the other eye. At the optic chiasm, the optic nerve fibers carrying information from the sides of the retina closest to the nose cross over to the other side of the brain, while those carrying information from the sides of the retina closest to the temples remain on the side of the brain where they are. After leaving the optic chiasm, the nerve fibers are referred to as the optic tract. Most of the nerve fibers in the optic tract end in the lateral geniculate nucleus of the thalamus, and from there the information will be passed on to the visual cortex.

Damage to the optic nerve can occur due to a variety of causes like trauma, tumors, stroke, or glaucoma. The deficit that occurs after damage depends on where the nerve is damaged, and involves some degree of visual defect or anopsia. If the damage occurs before the optic chiasm, then the patient will experience blindness in the eye supplied by that optic nerve. Damage to the middle of the optic chiasm will cause loss of the lateral visual field of both eyes, due to the way fibers from the nasal side of the retina cross over at this point. If the optic tract is damaged, one half of the visual field will be lost in both eyes.

Reference:

Vanderah TW, Gould DJ. Nolte's The Human Brain. 7th ed. Philadelphia, PA: Elsevier; 2016.

[nwqbjdo]

If the centre of the optic chiasm is damaged, isn't the medial visual field that is going to be lost? I got really confused at this part

[JonasStarklint]

Impressively descriptive and easy to understand for such a short video. Very nice with pictures of the field of vision lost corresponding to where the damage happens. Makes it easy to remember :D <3

[jaafarmohamed]

Such an informative and short video, and it's really well explained. Thanks a lot

[ednazhang]

Love the explanation for the deficits!

[aaronpogi]

thanks for this fast and informative video

[Brainstorm]

I always found the architecture of the visual stream to be super interesting. For instance: About 10x as many neuron-bundles go from V1 to LGN than the other way around. So there are 10 times as many feedback loops to the thalamus than feed-forward sensory information into the visual cortex. How crazy is that?!

[rohu]

That's was really short and very helpful thank u

[mohammedkhalil]

Very good...lam 2nd medicine college student ...love neurology

[rosebeltoloza]

Buen Día Doctor, disculpe, que relación tiene la Desmielizacion Neuronal con Neuritis Óptica.

[carrinaappling]

Hello, you really need to have a video on optogenetics.

[TheBetterGamer]

How does the optic nerve send signals? Is it electrical? Waves of some sort? I'm having trouble finding information about that specific detail. I understand "information" moves through the entire system but I don't understand how, or what the information is actually made of. All I keep getting is "this sends signals here, and that sends signals there" from websites.

[spurthichadharam]

Than you in think there can shall may vphv be octet nerve that is mainly responsible for focusing and image

[geno]

I did lose my optic nerve at age of 47! All I have is limited prefer vision! Can’t read menus or anything see anything on selves! I had to give up my drivers license! I have a lot of anxiety going on out

[FY-rchh]

My mom lost her peripheral eye sight in her left eye. She can see almost nothing to the left, can see some thing in front, and a bit better to the right. Her right eye's pherifiral vision is ok. But in your video you say that damage to the optic nerve affects BOTH EYES. What did then happendd to her left eye? Can it be brain damage on the right side? Maybe she did have a stroke? But she did have any other issues with health. She had very high blood pressure before the eye sight loss. Please answer my question. Thanks

[amarpal]

Is that it's traetment possible plz tell me

[mariagorretty]

quick question...
when the decussating fibers at the chiasm gets damaged....the medial part of vision of each eye should be damaged right?
dunno whether I'm right

[nomadickashmiri]

Im having a similar problem of optic kayaza I don't know how to spell that but I lost my right eye vision in an accident and I wanted to know if it can be cured

[nosoftspot]

Can Invision stem cells regenerating a dead optic nerve?

[Legallgaming]

What if u have amblyopia.. where is the damage to the optic nerve found?

[oykut]

do you have other cranial nerves video :)?