Neuroanatomy - The Visual Pathway (Visual Mnemonic)

preview_player
Показать описание
The neuroanatomy of the visual pathway can be confusing because there are several crossing points, but hopefully this visual mnemonic will help you remember how it all fits together.
First, let’s draw two eyes and define some terminology. Anything to the lateral margins of the retina is described as temporal, and towards the midline is described as nasal.
Visual information from the left visual field strikes the right side of both retinae (also described as the nasal side of the left retina and the temporal side of the right retina), and visual information from the right visual field strikes the left side of both retinae (also described as temporal side of the left retina and the nasal side of the right retina). This forms a W in our visual mnemonic
Next, the retina translates light signals into electrical signals that it conducts through axons of the optic nerve. Information from the temporal side of the left retina travels to the left lateral geniculate nucleus. Information from the nasal side of the left retina travels across the optic chiasm to the right lateral geniculate nucleus. Information from the nasal side of the right retina travels across the optic chiasm to the left lateral geniculate nucleus. In this way, information from the nasal sides of both retinae cross at the optic chiasm. Finally, information from the temporal side of the right retina travels to the right lateral geniculate nucleus.
As you can see, this way of drawing it forms a nice mnemonic – WIXI. You can see that all the information from the left visual field makes its way to the right geniculate nucleus. This makes sense because the right side of the brain controls the left half of the body, and vice versa.
One last thing to note is what happens if there is a lesion at the optic chiasm, such as when a patient develops a pituitary adenoma. Information from the temporal visual fields lands on the nasal halves of the retinae which then goes on to cross at the optic chiasm. So if this information flow were to be disrupted, the patient would experience bitemporal hemianopsia. Bitemporal because it is the temporal half of both visual fields that land on the nasal half of both retinae, and hemianopsia because the patient can’t… see… half of the visual field.

Thanks for watching! Be sure to like and subscribe for more videos.
Рекомендации по теме
Комментарии
Автор

Wish you didn't stop making videos. This was extremely helpful. I still subscribed, incase you continue.

silatikalaluka
Автор

Thanks for the memory aid with W IXI. Didn't notice that. It helps a lot, because Wixi resembles the german word for "fap" XD

TheThunderCracked