Neurons and vision Flashcards
Which part of the visual field do the inferior fibers represent?
The superior visual field
Which fibers cross at the optic chiasm?
The fibers from the nasal retina.
Where do 80% of post chiasmal fibers synapse?
Lateral Geniculate Nucleus
Where do 20% of post chiasmal fibers synapse?
Pretectal Nucleus (involved in pupil control)
Which fibers are affected in a Bitemporal hemianopsia?
Right and left nasal fibers
Which fibers are affected in a right hemianopsia?
Right nasal fibers & Left temporal fibers
Where is the lesion located in a Bitemporal hemianopsia?
At the optic chiasm
Where is the lesion located in a Right hemianopsia?
After the optic chiasm on the right optic tract
What does LGN stand for?
Lateral Geniculate Nucleus
What stimuli do layers 1 & 2 of the LGN detect?
Moving stimuli (Magnocellular pathway)
What stimuli do layers 3, 5 & 6 of the LGN detect?
Color and acuity (parvocellular pathway)
In how many layers do retinal fibers enter the LGN?
6 layers
What is the function of the LGN?
Functions as a relay station. It’s a point from which fibers that come in together are directed to different locations
What nerve fibers are damaged in a “pie in the sky” visual field defect?
Fibers from the inferior retina.
Through what lobe do the inferior fibers travel on their way to visual cortex?
Temporal lobe
