Quiz 2

Question 1

What is excitatory signaling in bipolar cells?

Answer 1

It speeds up the firing rate of bipolar cells.

Question 2

What is inhibitory signaling in bipolar cells?

Answer 2

It slows down the firing rate of bipolar cells.

Question 3

What is neural convergence?

Answer 3

It is the synapsing of a number of neurons onto one neuron.

Question 4

What are the steps of neural convergence?

Answer 4

1. Light entering the eye triggers a photochemical reaction in rods and cones at the back of the retina. 2. The chemical reaction activates bipolar cells. 3. Information is sent to the visual cortex via the thalamus.

Question 5

Which has more convergence, rods or cones?

Answer 5

Rods.

Question 6

How do receptor, bipolar, and ganglion cells pass signals?

Answer 6

Vertically.

Question 7

How do horizontal and amacrine cells pass signals?

Answer 7

Laterally.

Question 8

What does a bipolar cell receive signals from?

Answer 8

A bipolar cell gets a signal from a photoreceptor and two neighboring horizontal cells.

Question 9

Are all vertical signals excitatory or inhibitory?

Answer 9

Excitatory.

Question 10

Are all lateral signals excitatory or inhibitory?

Answer 10

Inhibitory.

Question 11

What is lateral inhibition?

Answer 11

It is the sending of inhibitory signals across the retina.

Question 12

True or False: Rods have more convergence than cones.

Answer 12

TRUE.

Question 13

Increased convergence leads to greater sensitivity but poorer what?

Answer 13

Detail.

Question 14

What is the phenomenon of lateral inhibition demonstrated through?

Answer 14

It can be demonstrated through the appearance of mach bands where you perceive a darker band on the edge of the lighter side because there is more inhibition coming from the darker side.

Question 15

How is the pattern of light from the left visual field processed?

Answer 15

It is processed by the right side of each eye and the lateral geniculate nucleus (LGN) and the right primary visual cortex.

Question 16

Where do most fibers from the optic nerve project?

Answer 16

To the LGN, but about 10% project to the superior colliculus.

Question 17

What is retinotopic mapping?

Answer 17

It maintains the spatial relationship from the retina to the LGN to the primary visual cortex.

Question 18

What is the function of the frontal lobe?

Answer 18

Taste.

Question 19

What is the function of the temporal lobe?

Answer 19

Hearing and smell.

Question 20

What is the function of the parietal lobe?

Answer 20

Touch.

Question 21

What is the function of the occipital lobe?

Answer 21

Vision.

Question 22

How many layers do LGN cells have?

Answer 22

6 layers: 2 inner and 4 outer.

Question 23

What do magno cells detect?

Answer 23

Movement (rods).

Question 24

What do parvo cells detect?

Answer 24

Details (cones) in the fovea.

Question 25

What is the structure of the primary visual cortex (V1)?

Answer 25

It has six layers, LGN projects to layer 4, and layer 4 projects to layers 3 and 2.

Question 26

What types of cells are found in V1?

Answer 26

No center surround, simple, complex, and hypercomplex cells.

Question 27

What can simple cells detect?

Answer 27

Location and orientation but cannot detect movement.

Question 28

What do complex cells respond to?

Answer 28

Moving lines/edges and are sensitive to the direction of motion but not sensitive to position.

Question 29

What do hypercomplex cells respond to?

Answer 29

Moving lines or edges of specific length.

Question 30

What is visual form agnosia?

Answer 30

A deficit in perceiving simple forms due to damage to the 'what' system in the temporal lobe.

Question 31

What is visual agnosia?

Answer 31

A failure in object recognition.

Question 32

What is optic ataxia?

Answer 32

Damage to the dorsal stream (parietal lobe) that leads to a failure to discriminate between objects and not being able to group them accurately.

Question 33

Onto what two structures do the ganglion cells synapse?

Answer 33

LGN and primary visual cortex.

Question 34

How is visual information processed when both eyes take in light from the right visual field?

Answer 34

The left visual field is processed by the right side of the brain and vice versa. 90% of optic nerve fibers project to the lateral geniculate nucleus, while 10% goes to the superior colliculus.

Question 35

How can the four types of ganglion cells in the frog be described?

Answer 35

Edge detector, bug detector, moving edge detector, dimming detector.

Question 36

What is a receptive field?

Answer 36

An area on the retina that, when stimulated, changes the activity of the cell.

Question 37

Distinguish between P (parvo) and M (magno) cells.

Answer 37

Parvo cells have smaller receptive fields, respond to sustained stimulus, and inform about detail. Magno cells have larger receptive fields, respond to transient stimulus, and are important for detection of movement.

Question 38

What brain area is damaged in blindsight?

Answer 38

The primary visual cortex.

Question 39

What is a double dissociation?

Answer 39

Two different functions involve two different mechanisms. Damage to structure A impairs function A but not B, and damage to structure B impairs function B but not A.

Question 40

How was a double dissociation shown with monkeys?

Answer 40

Damage to the temporal lobe removed object discrimination, while damage to the parietal lobe removed landmark discrimination.

Question 41

Where is evidence for face processing found?

Answer 41

In the area of the temporal lobe, ventral pathway.