Deck 6: The Visual System

Question 1

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

Answer 1

when the pupils are constricted.

Question 2

Which of the following can be found in large numbers at the blind spot?

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

Answer 2

the axons of retinal ganglion cells

Question 3

Which of the following is a small indentation?

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

Answer 3

fovea

Question 4

Rattlesnakes can see in

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

Question 5

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

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

Question 6

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 7

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 8

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 9

Prior to migraine attacks,sufferers often experience

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

Question 10

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 11

Binocular disparity

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

Question 12

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 13

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 14

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 15

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 A and C

Question 16

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 17

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 18

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.

Question 19

Which retinal structure is indicated by the pointer line?

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

Question 20

High-acuity vision is mediated by the

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

Question 21

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 22

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 23

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 24

Simple images that are stabilized on the retina start to

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

Question 25

Which retinal structure is indicated by the pointer line?

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

Question 26

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 27

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 28

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 29

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 30

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 31

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 32

Color vision is mediated by

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

Question 33

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 34

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 35

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 36

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 37

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 38

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 39

The bleaching of rhodopsin by light

A) hyperpolarizes rods.
B) depolarizes rods.
C) depolarizes cones.
D) opens sodium channels.
E) opens potassium channels.

Question 40

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 41

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 42

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) ipsilaterally.

Question 43

Mach bands are perceived 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 44

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 45

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 46

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 47

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 48

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 49

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 50

The perception of Mach bands results from

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

Question 51

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 52

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 53

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 54

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 55

Another name for primary visual cortex is

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

Question 56

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 57

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 58

Magnocellular neurons are particularly responsive to

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

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 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 61

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 62

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

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

Question 63

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 64

Some primary visual cortex neurons have receptive fields that can be divided into static "on" and "off" areas separated by straight edges.These primary visual cortex neurons are

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

Question 65

Complex visual cortex cells are __________ than simple cells.

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

Question 66

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 67

The major flow of information in the primary visual cortex is usually assumed to proceed 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 68

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 69

On the basis of their receptive field properties,most 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 70

Many binocular cells in the striate cortex

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 71

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 72

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 73

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 bipolar.

Question 74

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 75

Most binocular cells in the monkey striate cortex,

A) are hypercomplex.
B) are simple.
C) display ocular dominance.
D) do NOT respond to retinal disparity.
E) both C and D

Question 76

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 77

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 78

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 79

The receptive fields of most retinal ganglion cells are roughly

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

Question 80

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.