Visual Tracts (Phys, Tracts, Control of Eye Movements)

Question 1

What fibers target the inferior bank of the calcarine sulcus? (Lingual gyrus)

Answer 1

Upper quadrant of contralateral hemifields

Question 2

What is the affect of light on an on-center cell?

Cone stimulation

Answer 2

There is less glutamate, and this will cause the cell to depolarize.

Because there is less glutamate, there is less inhibition of the cation influx via the GCPR. The cation influx will continue, unbothered

Question 3

Purpose of Blobs

Answer 3

Color detection

Respond to specific wavelengths of light

Question 4

What receptors are present in the center of on-center cells?

Answer 4

GCPR

Question 5

Fxn of the dorsal pathway of visual processing

Answer 5

“Where” pathway
Passes through V3
Completes motor acts based on visual input

Question 6

Bipolar cell activation by Rods

Answer 6

Rods will converge on an on-center bipolar cell.

Rods also stimulate an amacrine cell, which will hijack the Cone pathway by synapsing on and stimulating ganglion cells.

Question 7

What is the affect of glutamate on an off-center cell?

Cone stimulation

Answer 7

The increased glutamate will bind to the AMPA receptor. This will cause an influx of cations and depolarize the cells

(AMPA is stimulated by glutamate)
Happens in DARK

Question 8

Where do ganglion cell axons coming from the nasal retina synapse?

Answer 8

Layers 1, 4, 6 of CL LGN

Question 9

Where is the blind spot

Answer 9

At the Optic Disk (where retinal axons leave the eye as the optic nerve)

Question 10

What retinal fields get an image from the RIGHT half of visual field?

Answer 10

Nasal aspect of Right retina

Temporal aspect of Left retina

Question 11

Pathway of smooth pursuit eye movements

Answer 11

1. Parietooccipital jxn
2. Pontine nuclei
3. Cross
4. Flocculonodular Cerebellum
5. Vestibular Nuclei

Question 12

Purpose of Ocular dominance columns

Answer 12

Eye dominance

Respond to input from either left or right

Question 13

Fxn of the pretectal area as a visual cortex area

Answer 13

pupillary light reflex

Question 14

What will seizures do to saccadic eye movements?

Answer 14

Eyes will deviate away from the gaze center

Question 15

What Brodmann’s area makes up the primary visual cortex?

Answer 15

Area 17

Question 16

What is the pathway of vision after the bipolar cells are depolarized?

Answer 16

Bipolar cell
Ganglion Cell (stimulated by glutamate)
Optic N.
Optic Chiasm
Optic Tract
Lateral Geniculate Body

Question 17

V1

Answer 17

Primary visual cortex

Edge and contour

Question 18

Where does the optic tract terminate?

Answer 18

Lateral geniculate nucleus (LGN)

Question 19

What receptor type is present in off-center cells?

Answer 19

non-NMDA (AMPA)

Question 20

V4

Answer 20

Brodmann 19

Color processing

Question 21

What fibers target the superior bank of the calcarine sulcus? (Cuneus)

Answer 21

Lower quadrant of contralateral hemifields

Question 22

Fxn of superior colliculus as a visual cortex area

Answer 22

Directs eye movements

Question 23

What Brodmann’s area makes up the visual association cortex?

Answer 23

Area 18 + 19

Question 24

Three phases of saccadic movements

Answer 24

Burst
Tonic
Pause

Question 25

What are the optic radiations?

Answer 25

Secondary neuron bundles arising from LGN

Question 26

Purpose of Orientation Columns

Answer 26

Angle of image

Respond to various visual line stimuli

Question 27

What retinal fields get an image from the LEFT half of visual field?

Answer 27

Nasal aspect of Left retina

Temporal aspect of Right retina

Question 28

V2

Answer 28

Brodmann 18

Depth perception

Question 29

BTP of Vertical saccades

Answer 29

Burst = RiMLF
Tonic = Nucleus of Cajal
Pause = omnipause cells of raphe

Question 30

V5

Answer 30

Middle Temporal

Question 31

BTP of Horizontal saccades

Answer 31

Burst = PPRF
Tonic = Nucleus prepositus Hypoglossal
Pause = omnipause cells of Raphe

Question 32

What are the Magnocellular layers of the LGN?

Answer 32

Layers 1-2

- Have rods; sensitive to moving stimuli

Question 33

What are the Parvocelluar layers of the LGN?

Answer 33

Layers 3-6

Question 34

Where do ganglion cell axons coming from the temporal retina synapse?

Answer 34

Layers 2,3,5 of IL LGN

Question 35

Glutamate levels in Light

Answer 35

Decreased

Question 36

What will destructive lesions do to saccadic eye movements?

Answer 36

Eyes will deviate towards the gaze center

Question 37

Glutamate levels in the Dark

Answer 37

Increased

Question 38

What is the affect of glutamate on a on-center cell?

Cone stimulation

Answer 38

Glutamate will cause the hyperpolarize, by blocking the influx of cations through the GCPR.

So in the dark, these cells will be hyperpolarized due to an increased amount of glutamate

Question 39

What is the affect of light on an off-center cell?

Cone stimulation

Answer 39

Because there is light, there is LESS glutamate.

Since AMPA cells function better under the influence of glutamate, their activity will be reduced when there is light.

This means less cation influx, causing the cell to HYPERPOLARIZE

Question 40

What aspect of the optic nerves deccussate at the optic chiasm?

Answer 40

Nasal portion of each optic N.

Temporal parts stay IL!

Question 41

Where is the object of attn focused and centered in the eye?

Answer 41

Fovea centrals and macula lutea

Question 42

Near Vision Response

Answer 42

1. Contraction of ciliary muscle (suspensory ligament relaxes, lens gets rounder)
2. Convergence of eyes to point of focus
3. Pupil constriction (reduces opening for light)

Question 43

Fxn of the ventral pathway of visual processing

Answer 43

“What” pathway

Gives us the ability to identify things

Question 44

What fibers make up the Myer’s loop?

Answer 44

Fibers running from the upper quadrant of CL hemifields (fibers going inferiorly)

Question 45

V3

Answer 45

Brodmann 18

Motion