Deck 6: The Visual System

Question 1

Which of the following can be found at the blind spot?

A) fovea
B) cones
C) the axons of retinal ganglion cells
D) the cell bodies of retinal ganglion cells
E) amacrine cells

Answer 1

the axons of retinal ganglion cells

Question 2

A fortification illusion often begins with

A) a headache.
B) a seizure.
C) a gray area of blindness near the center of the visual field.
D) a zigzag pattern of flickering lines.
E) thick lines in the periphery that then constrict.

Answer 2

a gray area of blindness near the center of the visual field.

Question 3

Which retinal structure is indicated by the pointer line?

A) fovea
B) retinal ganglion
C) blind spot
D) optic disk
E) cornea

Answer 3

blind spot

Question 4

The amount of light reaching the retinas is controlled by two donut-shaped bands of contractile tissue called the

A) pupils.
B) scleras.
C) corneas.
D) foveas.
E) none of the above

Question 5

With respect to vision, wavelength is to intensity as

A) vision is to audition.
B) wavelength is to color.
C) color is to brightness.
D) color is to loudness.
E) color is to pattern.

Question 6

Light passes through layers of the retina in which of the following sequences?

A) receptor layer, bipolar cell layer, retinal ganglion cell layer
B) retinal ganglion cell layer, horizontal cell layer, receptor layer
C) retinal ganglion cell layer, amacrine cell layer, receptor layer
D) both B and C
E) none of the above

Question 7

Binocular disparity

A) is an important depth-perception cue.
B) can be corrected by surgery.
C) can be corrected by glasses.
D) results from neural convergence.
E) is mediated by the lateral geniculate.

Question 8

Which of the following is a small indentation?

A) optic disk
B) fovea
C) retina
D) amacrine layer
E) pupil

Question 9

Which retinal structure is indicated by the pointer line?

A) fovea
B) retinal ganglion
C) blind spot
D) optic disk
E) cornea

Question 10

Depth of focus is normally greater

A) in dim light.
B) when the pupils are dilated.
C) when the pupils are constricted.
D) when the ciliary muscles are contracted.
E) both B and D

Question 11

Light enters the human eye through an opening in the iris called the

A) cornea.
B) fovea.
C) pupil.
D) retina.
E) sclera.

Question 12

The closer an object is, the

A) less our eyes converge when we focus on it.
B) less the disparity between the two retinal images of it.
C) smaller are its retinal images.
D) all of the above
E) none of the above

Question 13

In humans, all of the visual receptors are in the

A) last layer of the retina to be reached by light entering the eye.
B) first layer of the retina to be reached by light entering the eye.
C) cornea.
D) middle neural layer of the retina.
E) optic disk.

Question 14

High-acuity vision is mediated by the

A) optic disk.
B) blind spot.
C) fovea.
D) choroid.
E) sclera.

Question 15

Which of the following is accomplished by the ciliary muscles?

A) pupil constriction
B) accommodation
C) tracking
D) both A and B
E) both B and C

Question 16

A nanometer is a

A) tenth of a meter.
B) hundredth of a meter.
C) thousandth of a meter.
D) millionth of a meter.
E) billionth of a meter.

Question 17

Rattlesnakes can see in

A) what for humans would be complete darkness.
B) what for snakes is complete darkness.
C) infrared light.
D) both A and C
E) both B and C

Question 18

Prior to migraine attacks, sufferers often experience

A) headaches.
B) fortification illusions.
C) indigestion.
D) amnesia.
E) agnosia.

Question 19

When the pupils are constricted,

A) the retinal image is usually sharper.
B) there is usually greater depth of focus.
C) vision is poor in dim illumination.
D) all of the above
E) both B and C

Question 20

Unlike most other vertebrates, primates have

A) eyes that do not converge.
B) two eyes.
C) color vision.
D) two eyes side by side on the front of the head.
E) eyes that move.

Question 21

With respect to the visual system, a high degree of neural convergence is to a low degree of neural convergence as

A) low acuity is to high acuity.
B) high sensitivity is to low sensitivity.
C) photopic is to scotopic.
D) all of the above
E) both A and B

Question 22

The ability of a stationary eye to fill in the gap in its visual field that results from the blind spot is called

A) blind spotting.
B) completion.
C) convergence.
D) scotopic vision.
E) foveal summation.

Question 23

The Purkinje effect refers to the fact that

A) reds and yellows are brighter than blues and greens.
B) reds and yellows are more intense than blues and greens.
C) lights in the green-blue portion of the spectrum are brighter than lights in the yellow-red portion of the spectrum when viewed under dim illumination.
D) lights in the green-blue portion of the spectrum are brighter than equally intense lights in the yellow-red portion of the spectrum when viewed under dim illumination.
E) blue-greens are more intense than yellow-reds at night.

Question 24

Investigators have studied the contribution of eye movements to vision by studying the effects of

A) visual objects that do not move.
B) stabilized retinal images.
C) ciliary muscle paralysis.
D) neck muscle paralysis.
E) accommodation.

Question 25

Color vision is mediated by

A) the photopic system.
B) rods.
C) the scotopic system.
D) rhodopsin.
E) duplexity.

Question 26

High-acuity vision is mediated by

A) the photopic system.
B) the scotopic system.
C) the optic disks.
D) rhodopsin.
E) both C and D

Question 27

The color and brightness of large unpatterned surfaces are not directly perceived; they are filled in or completed by a process called

A) edge extrapolation.
B) area extrapolation.
C) surface interpolation.
D) accommodation.
E) binocular rivalry.

Question 28

The absorption spectrum of rhodopsin closely corresponds to the

A) scotopic spectral sensitivity curve.
B) colors of the rainbow.
C) absorption spectrum of cones.
D) photopic vision of humans.
E) photopic vision of fish.

Question 29

Mammals without cones tend to

A) be blind.
B) be nocturnal (active mainly at night).
C) eat lots of carrots.
D) be totally blind during the night.
E) live near the equator.

Question 30

Saccades are

A) connections between the photopic and scotopic systems.
B) blind spots.
C) eye movements.
D) centers of color vision.
E) retinal neurons.

Question 31

In comparison to the photopic system, the scotopic system has more

A) rods.
B) neural convergence.
C) receptors in the periphery of the retina.
D) sensitivity in dim illumination.
E) all of the above

Question 32

The bleaching of rhodopsin by light

A) hyperpolarizes rods.
B) depolarizes rods.
C) depolarizes cones.
D) opens Na⁺ ᶜʰᵃⁿⁿᵉˡˢ.
E) opens K⁺ ᶜʰᵃⁿⁿᵉˡˢ.

Question 33

Most of the cones are concentrated in the

A) nasal hemiretinas.
B) temporal hemiretinas.
C) foveas.
D) periphery of the retinas.
E) blind spot.

Question 34

The brightness of a light depends on its

A) intensity.
B) wavelength.
C) color.
D) both A and B
E) both A and C

Question 35

There are more rods

A) at the center of the fovea than there are 20° from the center.
B) in the nasal hemiretina than in the temporal hemiretina.
C) in the temporal hemiretina than in the nasal hemiretina.
D) both A and B
E) both A and C

Question 36

Simple images that are stabilized on the retina

A) vibrate.
B) continually disappear and reappear.
C) change shape.
D) increase in brightness.
E) move to the midline.

Question 37

The photopic spectral sensitivity curve of a person can be determined by having the person report the

A) intensity of various wavelengths of light shone on the fovea.
B) brightness of various wavelengths of light shone on the fovea.
C) intensity of various wavelengths of light shone on the periphery of the retina.
D) brightness of various intensities of light shone on the periphery of the retina.
E) both B and D

Question 38

High-acuity, color vision is mediated by the small foveal area of the retina.Nevertheless, we have perceptions of the world that are expansive in both their color and their detail.This is possible because

A) our visual systems integrate the foveal images from recent visual fixations to produce the subjective visual perception that we are experiencing at any instant.
B) of the optic disks.
C) of retinal disparity.
D) of the difference between the photopic and scotopic spectral sensitivity curves.
E) we have depth perception.

Question 39

Transduction refers to the

A) perception of lights.
B) disappearance of visual stimuli.
C) transmission of sensory signals to the cortex.
D) transmission of visual signals to the cortex.
E) translation of one form of energy to another.

Question 40

The reaction that transduces light into an electrical signal in rods is the

A) bleaching of rhodopsin by light.
B) elicitation of action potentials in rods.
C) turning red of rhodopsin.
D) inhibition of action potentials in rods.
E) elicitation of action potentials in cones.

Question 41

In humans, the axons of retinal ganglion cells whose cell bodies are in the left temporal hemiretina

A) project contralaterally.
B) project ipsilaterally.
C) terminate in the right lateral geniculate nucleus.
D) terminate in the right striate cortex.
E) both A and C

Question 42

The perception of Mach bands results from

A) ommatidia.
B) mutual excitement.
C) mutual consent.
D) lateral facilitation.
E) lateral inhibition.

Question 43

Here is an illustration of the retina.The neurons identified by the pointer lines carry signals from the retina to the lateral geniculate nuclei.These neurons are

A) lateral geniculate cells.
B) bipolar cells.
C) retinal ganglion cells.
D) horizontal cells.
E) amacrine cells.

Question 44

Lateral inhibition in horseshoe crab ommatidia is mediated by the

A) limulus.
B) lateral geniculate.
C) lateral neural network.
D) amacrine layer.
E) horizontal cell layer.

Question 45

The parvocellular layers of the lateral geniculate nuclei get their name from the fact that the neurons in these layers are

A) multipolar.
B) small.
C) monopolar.
D) large.
E) parvo-like.

Question 46

The perception of an edge is in effect the perception of a

A) line.
B) line separating two adjacent areas of the visual field.
C) contour.
D) contrast between two adjacent areas of the visual field.
E) line between two adjacent areas of the retina.

Question 47

A compelling illustration of contrast enhancement is

A) the complementary color afterimage demonstration.
B) the Mach band demonstration.
C) lateral inhibition.
D) color constancy.
E) the cocktail sausage demonstration.

Question 48

The retina-geniculate-striate system is organized

A) from top to bottom.
B) from left to right.
C) on the basis of wavelength.
D) retinotopically.
E) contralaterally.

Question 49

Parvocellular is to magnocellular as

A) 2 is to 4
B) small is to big.
C) movement is to fine detail.
D) all of the above
E) none of the above

Question 50

Projections to the visual cortex from the lateral geniculate nuclei terminate in cortical layer

A) I.
B) II.
C) III.
D) IV.
E) V.

Question 51

Magnocellular neurons are particularly responsive to

A) color.
B) detail.
C) stationary patterns.
D) movement.
E) all of the above

Question 52

Most lateral geniculate neurons terminate in

A) the primary visual cortex.
B) cortical layer IV.
C) the contralateral hemisphere.
D) both A and B
E) both A and C

Question 53

The parvocellular neurons are particularly responsive to

A) color, fine detail, and stationary objects.
B) moving objects, large patterns, and color.
C) black and white, stripes, and moving objects.
D) color, fast moving objects, and faces.
E) large, moving objects.

Question 54

Mach bands occur because

A) if A fires less than B, B must fire more than C.
B) the visual receptors near an edge become hyperpolarized.
C) visual receptors on the more intense side of an edge receive more lateral inhibition than receptors on the less intense side.
D) visual receptors on the more intense side of an edge receive less lateral inhibition than receptors on the less intense side.
E) visual receptors adjacent to an edge on the more intense side receive less lateral inhibition than do receptors farther from that edge, and because visual receptors adjacent to the edge on the less intense side receive more lateral inhibition than do receptors farther from that edge.

Question 55

The bleaching of rhodopsin by light

A) triggers inhibitory effects.
B) closes rod sodium channels.
C) hyperpolarizes the rods.
D) reduces the release of glutamate from rods.
E) all of the above

Question 56

The parvocellular component of the retina-geniculate-striate system runs through the __________ layers of the lateral geniculate nuclei.

A) top 4
B) top 2
C) bottom 4
D) bottom 2
E) middle 2

Question 57

Another name for primary visual cortex is

A) lateral geniculate cortex.
B) retino cortex.
C) striate cortex.
D) foveal cortex.
E) optic cortex.

Question 58

Nonexistent stripes of lightness and darkness that accentuate the perception of edges are often called

A) lateral inhibitions.
B) lateral plexuses.
C) ommatidia.
D) hallucinations.
E) Mach bands.

Question 59

The retina-geniculate-striate system terminates in the

A) striate cortex.
B) primary visual cortex.
C) neocortex of the parietal lobe.
D) both A and B
E) both A and C

Question 60

The major distortion in the retinotopic layout of the primary visual cortex is the disproportionately

A) high cortical representation of the fovea.
B) low cortical representation of the fovea.
C) low cortical representation of color.
D) high cortical representation of movement.
E) low cortical representation of movement.

Question 61

Primary visual cortex neurons

A) are circular.
B) are grouped in functional vertical columns.
C) have straight edges.
D) are larger than the "off" areas.
E) are rectangular.

Question 62

Some binocular striate cells

A) display ocular dominance.
B) respond best to retinal disparity.
C) are in the temporal lobe.
D) both A and B
E) both A and C

Question 63

Neurons in lower layer IV of striate cortex

A) all have receptive fields in the fovea.
B) all have receptive fields in the periphery of the visual field.
C) receive virtually all their input from the left eye.
D) receive virtually all their input from the right eye.
E) are all monocular.

Question 64

The receptive field of a visual neuron is the area of the

A) striate cortex within which stimulation can activate the neuron.
B) striate cortex within which stimulation can inhibit the neuron.
C) visual field within which the suitable visual stimulus can influence the firing of the neuron.
D) retina within which stimulation with diffuse light can activate the neuron.
E) either A or B

Question 65

The pattern called "off firing" involves a temporary

A) decrease in firing when the stimulus comes on.
B) increase in firing when the stimulus goes off.
C) decrease in firing when the stimulus goes off.
D) both A and B
E) both A and C

Question 66

Neurons with receptive fields in the fovea

A) are all on-center cells.
B) are all off-center cells.
C) have particularly small receptive fields.
D) are all rods.
E) are all cones.

Question 67

The receptive fields of most retinal ganglion cells are roughly

A) square.
B) round.
C) rectangular.
D) perpendicular.
E) columnar.

Question 68

Simple cells of the primary visual cortex

A) have receptive fields with static "on" and "off" areas that are separated by a straight edge.
B) do not have receptive fields.
C) have receptive fields that cannot be divided into static "on" and "off" areas.
D) have two receptive fields.
E) are in lower layer IV.

Question 69

In general, neurons of the retina-geniculate-striate system respond weakly to

A) monocular stimuli.
B) diffuse light.
C) contrast.
D) circles of light.
E) circular edges.

Question 70

Unlike retinal ganglion cells, lateral geniculate cells, and simple cortical cells, over half of the complex cortical cells of monkeys

A) are retinotopic.
B) have receptive fields.
C) are binocular.
D) are monocular.
E) have photopigments.

Question 71

In general, information in the primary visual cortex is thought to flow from __________ to __________ to __________.

A) lower layer IV; simple cells; complex cells
B) lower layer IV; complex cells; simple cells
C) simple cells; lower layer IV; complex cells
D) simple cells; complex cells; lower layer IV
E) complex cells; simple cells; lower layer IV

Question 72

Complex visual cortex cells are __________ than simple cells.

A) much bigger
B) much smaller
C) more numerous
D) less numerous
E) more inhibitory

Question 73

Like simple cells, complex cortical cells

A) have rectangular receptive fields.
B) respond best to straight-line stimuli in a particular orientation.
C) are unresponsive to diffuse light.
D) respond to contrast.
E) all of the above

Question 74

Hubel and Wiesel's method of studying neural coding in sensory systems involves

A) defining the receptive fields of individual neurons.
B) determining which stimuli have the most effect on the firing of an individual neuron when they are presented in its visual field.
C) starting at the periphery of a system and progressively studying neurons at "higher" and "higher" levels of the system.
D) all of the above
E) none of the above

Question 75

The receptive fields of complex cortical cells are __________ than those of simple cortical cells.

A) bigger
B) smaller
C) more circular
D) less circular
E) more monocular

Question 76

On the basis of their receptive field properties, the neurons in lower layer IV of the primary visual cortex are classified as

A) simple cells or complex cells.
B) complex cells or hypercomplex cells.
C) hypercomplex cells.
D) on-center or off-center cells.
E) type A or type B cells.

Question 77

When a light is shone in the periphery of the receptive field of an on-center cell,

A) there is an immediate period of inhibition and then a burst of firing when the light is turned off.
B) the firing of the cell is increased until the light is turned off.
C) the firing of the cell is inhibited after the light has been turned off.
D) the cell is silent until the light comes on again.
E) the cell is almost silent until the light comes on again.

Question 78

In essence, on-center and off-center cells of the retina-geniculate-striate system respond best to

A) straight lines.
B) movement.
C) contrast.
D) circles.
E) dots of light.

Question 79

Neurons of the primary visual cortex that have receptive fields that can be divided into static "on" areas and "off" areas separated by straight edges are

A) geniculate cells.
B) binocular cells.
C) simple cells.
D) complex cells.
E) hypercomplex cells.

Question 80

In the monkey striate cortex, most binocular cells

A) are hypercomplex.
B) are simple.
C) display ocular dominance.
D) are sensitive to contrast.
E) both C and D