Higher Order Vision

Question 1

What is the fovea?

Answer 1

The center of retina where vision is sharpest and most acute

Question 2

What is the fovea made up of?

Answer 2

The fovea is mostly made up of cones and has a 1:1:1 ratio of cone to bipolar to ganglion. It has smaller receptive fields but can see much more in detail

Question 3

What is the peripheral retina?

Answer 3

Peripheral retina used for allowing us to see our surroundings while focused on something else. It is made up of mostly rods and has a larger receptive field. Less detail than the fovea. There is also more photoreceptors to a bipolar cell and more bipolar cells to a ganglion cell.

Question 4

What is the retinofugal pathway

Answer 4

Connects the retina to the primary visula cortex(V1) through the lateral geniculate nucleus(LGN)

Question 5

Where do 90% of retinal ganglion cells synapse?

Answer 5

The LGN then on to the visual cortex

Question 6

Where does the other 10% go?

Answer 6

They go to specialized subcortical regions that are divided between the retina to superior colliculus, retina to pretectum, and retina to hypothalamus

Question 7

What do each subcortical region specify in?

Answer 7

1. Retina to superior colliculus helps our head adjust towards the object we want to see
2. Retina to pretectum helps the pupils contract
3. Retina to hypothalamus sets our circadian ryththm which is our internal 24-hour clock

Question 8

What does the optic chaism do?

Answer 8

It allows information from both eyes to be processed

Question 9

How do crossing fibers work?

Answer 9

Nerves from the inner eyes process the visual information and send the signal to the opposite tracts.

Question 10

How do non-crossing fibers work?

Answer 10

Visual information processed on the outer eye or temporal hemiretina will stay on their tract

Question 11

What side of the brain process each visual field and how do we know?

Answer 11

The left side of the brain sees the right half of the world and vice versa. The right visual field falls on the nasal hemiretina of the right eye meaning it crosses tracts, and it also falls on the temporal hemiretina of the left eye meaning it stays on that tract. This is the same way the left eye processes just with opposite hemiretinas

Question 12

Why do prey and predator tend to have different eye placements?

Answer 12

Prey tend to have eyes closer to the side and have a higher sense of monocular vision then binocular vision. This is for having better all around vision. Predators tend to have eyes placed in the front and have better binocular vision so the can keep track of their pray when chasing them

Question 13

What is the lateral geniculate nucleus (LGN)?

Answer 13

The thalamic nucleus that processes and transmits visual information

Question 14

Where does the LGN recieve its input?

Answer 14

The retinal ganglion cells

Question 15

Which LGN layers are magnocellular and what are distinguishable characteristics?

Answer 15

Layers 1 and 2 have visibly larger cell bodies, take input from M type ganglion cells, are mostly made up of rods, and process pattern and motion

Question 16

Which LGN layers are paravocellular and what are distinguishable characteristics?

Answer 16

Layers 3, 4, 5, and 6 have smaller neurons/cell bodies, take input from P type ganglion cells, made up of mostly cones, and processes color and fine detail

Question 17

What is orientation column?

Answer 17

Highly organized, all neurons in the same vertical stack tend to have same preffered orientation