Visual Pathway and Lesions

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[champagnepogi]

the order is optic nerve, optic chiasma, optic tract, lateral geniculate body, optic radiations then visual cortex basically

[abinraji]

There is a mistake in this video fibres from temporal hemiretina donot cross, while the fibres from nasal hemiretina cross.

[haneenal-hiari]

Thank you, you’ve made it much easier 🤍

Optic nerve —> optic chiasm —> optic tract —> (thalamus) lateral geniculate body —> visual cortex (occipital ) as optic radiation

[abdojamal]

He's absolutely right, it's all a matter of confusion on your part, and suboptimal explanation on his. Just know the Main Fact and the Main Confusion Point and that will clear up any mist (But before i say them, keep in mind that by saying right or left visual fields i mean the right or the left parts of the SINGLE picture you perceive eventually):

1- The Main Fact: The Right visual field is perceived by the left cortex and vice versa,
That's the GOLDEN rule, so keep that in mind as a precondition that has to be fulfilled; so if we want the RT field to be perceived by the left cortex we need A) left temporal fibers and B) Right nasal fibres; and that's simply because the temporal ones don't cross while the nasal ones do. If we were to use the Right temporal fibres (temporal fibres of the Right eye) to perceive the right visual field, that would mean that it would have been perceived by the right cortex, and that would have violated our precondition.
Remember that we're talking about the visual field as a whole; as a SINGLE picture. Now let's take the visual field of the right eye setting aside the left one for a second. You need to know that the right eye sees both right and left visual fields (right and left parts of the visual field), so cover the left eye for me for a second and see only with the right one: You'll see the right part of your one-eye visual field using the nasal fibres which will cross and go to your LEFT cortex. the left part of your one-eye (the right one remember) visual field on the contrary, is perceived using the temporal fibres, which will stay on the same side, till it reaches the RIGHT cortex; that means that a man with only one functional eye uses both his right and left cortices!!

2- The Main Confusion Point: Students most often confuse between temporal fibres and temporal part of visual field. and to clear that confusion, just know that the RIGHT part of your visual field has a temporal and a nasal portion (you can think of it as peripheral and central it's only a matter of terminology), so as the left part of that visual field (it has temporal and nasal portions too).
The temporal portion of the right visual field is perceived by nasal fibres of the right eye, while the nasal portion of the right visual field is perceived by temporal fibres of the left eye. Read those last couple of sentences again and case closed.

[AndreaJoseph]

This video is perfectly correct in the crossover concept. The axons at the "nasal" retina are responsible for "temporal" vision. That's what is labelled in the video.These cross over at the chiasma. Similarly, the axons at the "temporal" retina are responsible for" nasal" vision.

[tejuoladeji]

i read in my textbook that the fiber from the nasal half of the retina of each side cross to the contralateral while the fibers representing the temporal half REMAINS UNCROSSED

[melaniegarrett]

THE SIMPLEST VIDEO ON YOUTUBE! I've been confused over and over again. Thank you for teaching it with clarity

[madmedicos]

This man just need one page to clear every concepts of the topic😎 you’re incredible 🤩 Thanks a lot sir!❤

[lingsjournal]

This is an amazing resource and lovely hand drawn diagrams. Clear explanation too. I remember doing this in my first year of med school and it still sticks with me today!

[victormuhia]

armando you are the best artist in explanation videos never listen to foolish critics we respect and appreciate you

[Marahxtb]

What he labelled in the video is correct.
Notice the difference; he drew fields AND eyes (the small balls/circles):
Fibers coming from temporal field of vision, go to nasal part of the eye and cross (because they ARE NASAL FIBERS but they give info about temporal(lateral) field/vision), and temporal fibers of temporal part of the eye that don’t cross give info about the nasal field (medial field) and do not cross. There's a difference between vision and fibers. It's always the opposite.

[suhaillone]

Actually this video is perfectly alright.
Let me explain because the uploader thought we are genius and some of us know and some of us dont know few fundamentals.

Basically for example lets take left eye
We know there are two type of fibres nasal and temporal.
Nasal fibres carry temporal field of vision of same eye and temporal fibres carry nasal visual field of same eye.
I hope now u understand the video 😊

[blenli]

I was really confused about this concept until I watched your helpful video. Thank you for this!

[AminaTanko-hr]

According to my textbook it say the visual cortex receives information from the temporal part of the same side while the nasal part of the opposite side which means the nasal part is the one crossing not the temporal part

[khadijah.b]

Optic tract is before lateral geniculate body, optic radiation is the one after Lgb

[arpithapereira]

you hv mislabelled optic tract. its the optic radiations

[rafayshahzad]

So the order is optic nerve, optic chiasm, optic tract, lateral geniculate body, optic radiation, visual cortex

[szdtihf]

This is just my perspective, so take it for what it's worth. If you ever redo this video, if you draw the two temporal retinal pathways first at the very outset and indicate the nasal fields they cover and then draw the nasal retinal pathways and the temporal fields they cover, it would be a lot easier for students to grasp what's going on IMHO. However, great job as always. Love your videos.

[Neditarts.]

I have been difficulting in understanding it you explain it so awesomely and simply That I understand it so good thank you so much🌺🌺🌺🙏🙏🙏🙏

[Bombastic]

there is a mistake in the optic tract, the right information is ::
Left optic tract – contains fibres from the left temporal (lateral) retina, and the right nasal (medial) retina.
Right optic tract – contains fibres from the right temporal retina, and the left nasal retina.