Optic nerve (7.3)
The optic nerve is also known as...
Cranial nerve II
Where do the 2 optic nerves converge?
In the optic chiasm
True or False: Information in the right vision field being perceived by the left eye will cross over the optic chiasm to end up in the right hemisphere.
False: It won't cross over, rather stay in the left hemisphere
How many layers does the LGN have?
6
True or False:
The two streams of communication are independent of each other.
False
Info that comes from the left visual field hits which half of the left eyeball?
The left or temporal side
What can glaucoma result in?
Blindness
What role does the choroid have?
Supplying blood to the retina
What is the first synapse formed at the optic nerve, the LGN, actually called (what does it stand for/un-abbreviated form?)
lateral geniculate nucleus
What are saccades?
When you're shifted your focus from one object to the next, your eyes made tiny, rapid, jerking motions over the different objects
Info that comes from the right visual field hits which half of the left eyeball?
The right or nasal side
What does "smooth pursuit mean"?
The ability for the eyes to follow something unconsciously as it moves across your field of view
What structure represents the start of central processing, the majority of the time?
Thalamus
If I were to take layer 1 of the LGN would it be closer to the persons back or stomach? (Ventral or dorsal?)
Ventral or stomach
What are two other names for the primary visual cortex?
V1 and striate cortex
What are the 2 alternate signaling pathways mentioned?
The pretectal area and the retinohypothalamic tract (RHT)
What are 2 of the causes of glaucoma?
High intraocular pressure, physical trauma, medications, or a natural genetic weakness of the nerve
Based on the knowledge that the stimuli is being sensed from the nasal portion of the head, is the information perceived ipsilaterally or contralaterally?
Contralaterally
What are the three types of neurons that the LGN is made up of?
Magnocellular, parvocellular and koniocellular
After V2, visual information passes through two streams of communication. What are they called?
Dorsal stream and ventral stream
Explain the path info takes from the left half of the left eye to the thalamus
The info goes through the optic nerve to the optic chiasm, then it stays in the brain's left hemisphere and goes to the thalamus
What is the RHT's use?
To conduct light info to suprachiasmatic nucleus, impacts the body’s circadian rhythms
What region of the brain is the visual stimuli sent to for primitive visual functions?
The mid-brain, more specifically the pretectal area
The outputs of the LGN are a series of axonal bundles called...
Optic radiations
Imagine you are a prehistoric organism living in a food-scarce environment. Approaching a small berry tree, you would use which stream structures to correlate the berries with memories?
Ventral stream