4 - The Visual Pathway

Question 1

10 layers of the retina:

Answer 1

RPE
Photoreceptors
External Limiting Membrane
Outer Nuclear
Outer Plexiform
Inner Nuclear
Inner Plexiform
Ganglion Cell
Nerve Fiber Layer
Inner Limiting Membrane

Question 2

the visual pathway begins in the photoreceptors, followed by 3 neuron chain:

Answer 2

bipolar - ganglion - neurons in LGN of thalamus

Question 3

photoreceptors release glutamate to bipolar cells in _

Answer 3

the dark (inhibitory)

Question 4

OFF bipolar cells are _ receptors
less glutamate (light) = _ cation conductance
cell _

Answer 4

ionotropic
less
hyperpolarizes (does not fire)

Question 5

ON bipolar cells are _ receptors
less glutamate (light) = _cation conductance
cell _

Answer 5

metabotropic
more
depolarizes (AP fired)

Question 6

ON and OFF cells are always working to detect changes in light levels
increased light - _ depolarizes
decreased light - _ depolarizes

Answer 6

ON

OFF

Question 7

ON bipolar cell synapses with _ ganglion cell;

ON ganglion cell _ when signal comes from center as opposed to surround

Answer 7

ON

fires more rapidly

Question 8

3 ganglion cell types:

Answer 8

midget, parasol, bistratified

Question 9

Midget ganglion cells make up the majority of the cells that project to the _
origin of the _ pathway

Answer 9

LGN

parvocellular

Question 10

parasol ganglion cells make up _% of cells that project to LGN
origin of the _ pathway

Answer 10

10

magnocellular

Question 11

bistratified ganglion cells make up _% of cells that project to LGN
origin of _ pathway

Answer 11

8

koniocellular

Question 12

midget cells (parvo) detect _
parasol cells (magno) detect _
bistratified (konio) detect _

Answer 12

color (R/G), detail
motion, contrast, shape
blue and yellow

Question 13

projection of visual fields on each retina are _ and _

Answer 13

inverted and perverted

Question 14

at LGN, visual field information is _

Answer 14

lateralized

Question 15

some fibers _ LGN

Answer 15

bypass

Question 16

bypass LGN:

pupillary fibers -> _

Answer 16

pretectal nucleus

Question 17

bypass LGN:

superior colliculus ->

Answer 17

saccadic eye movements

Question 18

bypass LGN:

pulvinar ->

Answer 18

visual salience (what’s important)

Question 19

at optic radiations, there is separation of _

Answer 19

superior and inferior fields

Question 20

optic radiations mneumonic:

Answer 20

SMILe

Question 21

optic radiations:

Superior fibers travel _

Answer 21

Medially through parietal lobe

Question 22

optic radiations

Inferior fibers travel _

Answer 22

Laterally through temporal lobe

Question 23

superior optic radiations (inferior visual field) reach primary visual cortex _ to calcarine fissure

Answer 23

superior

Question 24

inferior optic radiations (superior visual field) reach primary visual cortex _ to calcarine fissure

Answer 24

inferior

Question 25

_ fibers swing out creating Meyer's loop

Answer 25

inferior optic radiations

Question 26

optic radiations lesion mneumonic:

Answer 26

PITS (parietal lesion = inferior field defect) (temporal lesion = superior field defect)

Question 27

primary visual cortex is characterized by wide layer _

Answer 27

VI

Question 28

layer VI (primary visual cortex) contains extra band of myelinated fibers, and is called _

Answer 28

striate cortex

Question 29

the primary visual cortex is organized in _ columns

Answer 29

retinotopic

Question 30

2 types of cortical columns:

Answer 30

ocular dominance columns | orientation columns

Question 31

the primary visual cortex is located _

Answer 31

superior and inferior to calcarine sulcus on occipital lobe

Question 32

majority of LGN fibers _ at V1

Answer 32

terminate

Question 33

central vision (macula) is represented where in V1?

Answer 33

posterior

Question 34

peripheral vision is located where on V1?

Answer 34

anterior

Question 35

optic chiasm lesion, ex pituitary tumor creates what kind of defect?

Answer 35

bitemporal

Question 36

``` Ventral stream _ pathway projects to _ lobe responsible for _ lesions cause: ```

Answer 36

parvo (what) temporal color, patterns, shapes difficulty recognizing objects and deficits in attention to visual cues

Question 37

Dorsal stream _pathway projects to _ lobe responsible for

Answer 37

Magno (where) parietal visual space, navigation thru space