Chapter 5: Vision

Question 1

Damage to the MT and MST would result in which condition?
a. Double vision
b. Visual agnosia
c. Color blindness
d. Motion blindness

Answer 1

Motion blindness
The MT (middle temporal cortex) and MST (medial superior temporal cortex) are responsible for detecting objects that are moving in the visual field. This is important because information about moving objects can be lifesaving. Damage to these areas would result in a person being unable to detect that an object is moving and which direction it is travelling.

Question 2

In the visual system, the _____ stream is the “how” pathway whereas the ____ stream is the “what” pathway.
a. dorsal; ventral
b. ventral; anterior
c. ventral; dorsal
d. anterior; ventral

Answer 2

Dorsal; Ventral
The incoming visual information is processed in many ways. The dorsal stream through the parietal cortex provides information about “how” because of its importance for visually guided movements. The ventral stream through the temporal cortex provides information that allows us to identify and recognize objects

Question 3

Although her vision is intact, Karin has an inability to recognize objects. She likely has _____.
a. astigmatism
b. glaucoma
c. parietal cortex damage
d. a visual agnosia

Answer 3

Visual Agnosia
Karin has a visual agnosia as the result of damage to the temporal cortex. Agnosias can be very specific, such as prosopagnosia, which is an inability to recognize faces.

Question 4

In terms of the development of visual processing skills, ____.
a. younger children perceive the whole more than they do the parts
b. these abilities are at a level similar to those of adults by age eight
c. older children can perceive the whole or the parts, but not both
d. mature skills do not emerge until the late teens

Answer 4

Younger children perceive the whole more than they do the parts

Question 5

When processing visual patterns, older children, like adults ____.
a. use the left hemisphere when processing the whole pattern but the right when processing the parts of the pattern
b. show wide activation throughout visual processing areas whether processing the whole or parts
c. are capable of using either hemisphere for processing the whole or parts, and do so interchangeably
d. use the right hemisphere when processing the whole pattern but the left when processing the parts of the pattern

Answer 5

Use the right hemisphere when processing the whole pattern but the left when processing the parts of the pattern

Question 6

The video describes how a child who had a stroke at age 5 would reproduce the pi image at age 8. Based on your understanding of how the brain processes images, which of the following patterns of results would you expect from the child at age 12?
a. the child will be able to reproduce the image like a typical 12-year-old, with brain activity concentrated in the uninjured hemisphere.
b. the child will be able to reproduce the image like a typical 8-year-old, with brain activity concentrated in the uninjured hemisphere.
c. the child will be able to reproduce the image like a typical 12-year-old, with brain activity similar to a typical 12-year-old.
d. the child will be able to reproduce the image like a typical 8-year-old, with brain similar to a typical 8-year-old.

Answer 6

The child will be able to reproduce the image like a typical 12-year-old, with brain activity concentrated in the uninjured hemisphere.

Question 7

Complex cells have large receptive fields with no fixed excitatory or inhibitory zones that respond to moving bars of light at varying angular orientations.

What are Hypercomplex cells?

Answer 7

Hypercomplex cells have receptive fields that have some properties of both simple and complex cells: these have large excitatory zones with smaller inhibitory zones, responding to moving bars of light of varying angular orientation.

Question 8

What is an optic nerve?

Answer 8

group of ganglion cell axons that exit through the back of the eye

Question 9

What is the area at the back of the retina devoid of receptors

Answer 9

Blindspot

Question 10

What is the tiny area of the retina specialized for acute, detailed vision?

Answer 10

Fovea

Question 11

What is the law of specific nerve energies?

Answer 11

rule that whatever excites a nerve always sends the same information to the brain

Question 12

What is a cone?

Answer 12

type of retinal receptor that contributes to color perception

Question 13

What is the neuron in the fovea of humans and other primates

Answer 13

midget ganglion cell

Question 14

What is a bipolar cell?

Answer 14

type of neuron in the retina that receives input directly from the receptors

Question 15

What is a ganglion cell?

Answer 15

type of neuron in the retina that receives input from the bipolar cells

Question 16

What is a visual field?

Answer 16

area of the world that an individual can see at any time

Question 17

What is a chemical contained in rods and cones that release energy when struck by light?

Answer 17

Photopigment

Question 18

The law of specific nerve energies was stated by ____.
a. Hermann von Helmholtz
b. Johannes Müller
c. David Hubel
d. Torsten Wiesel

Answer 18

Johannes Müller

Question 19

The area of the retina that is specialized for acute, detailed vision is the ____.
a. iris
b. cornea
c. fovea
d. amacrine convergence

Answer 19

fovea

The fovea has a high concentration of cones. As such, it is the area of highest acuity on the retina.

Question 20

Toward the periphery of the retina, more and more receptors converge onto bipolar and ganglion cells and, as a result, ____.
a. the brain cannot detect the exact location of a peripheral light source
b. color vision is especially acute
c. the periphery is largely insensitive to dim light
d. individuals experience what is commonly called the “blind” spot

Answer 20

the brain cannot detect the exact location of a peripheral light source

The cells in the periphery are extremely sensitive to movement due to the large numbers of rods that converge onto bipolar then retinal ganglion cells. However, this convergence reduces the ability to have high acuity as in the fovea.

Question 21

The ganglion cells in the fovea of humans and other primates are called ____.
a. horizontal cells
b. amacrine cells
c. midget ganglion cells
d. bipolar cells

Answer 21

midget ganglion cells

Each cell is small and responds to just a single cone (hence the high acuity). They provide up to 70 percent of the input to your brain.

Question 22

Jaquan has gone outside and forgot his sunglasses. What will happen to his rods in bright daylight?
a. Their sensitivity to color will be increased.
b. They will be bleached.
c. They will become more active.
d. Their sensitivity to detail will increased.

Answer 22

They will be bleached

Ideally, rods respond in dim light. In bright light, they become photobleached and cannot respond.

Question 23

Foveal vision ____.
a. contains cones as receptors
b. responds well to dim light
c. is not good at distinguishing detail
d. has very limited color vision

Answer 23

contains cones as receptors

The fovea has a high concentration of cones that respond to color and bright light. As such, it is the area of highest acuity on the retina.

Question 24

Cones provide about ___ of the visual input to the brain.
a. 60 percent
b. 70 percent
c. 80 percent
d. 90 percent

Answer 24

90 percent

Although rods outnumber cones almost 20:1 in the human retina, cones provide about 90 percent of the brain’s input.

Question 25

According to the trichromatic theory, which of the following best explains how/why we discriminate among wavelengths of light?
a. We use the sum of the activity in all three types of cones.
b. We use a difference in activity between the most and least active types of cones.
c. We use the ratio of activity across the three types of cones.
d. We use the activity of the most active cone.

Answer 25

We use the activity across the three types of cones

Also known as the Young-Helmholtz theory, the trichromatic theory suggests that we discriminate among wavelengths of light by the ratio of activity across the three types of cones (short-, medium-, and long-wavelength).

Question 26

The ____ theory posits that we perceive color on a continuum from red to green, another from yellow to blue, and another from white to black.
a. trichromatic
b. retinex
c. Young-Helmholtz
d. opponent process

Answer 26

opponent process

The opponent process theory suggests that we perceive color in terms of opposites (for example, yellow and blue) and can explain such visual artifacts as an afterimage.

Question 27

The ____ theory can account for the constancy of color across different lighting conditions.
a. trichromatic
b. retinex
c. Young-Helmholtz
d. opponent process

Answer 27

retinex

The retinex theory explains phenomenon such as color constancy and suggests that the cortex compares information from various parts of the retina to determine features such as brightness and color.

Question 28

In mammalian vision, most ganglion cell axons go to the ____ of the thalamus.
a. lateral geniculate nucleus
b. hippocampus
c. amygdala
d. somatosensory cortex

Answer 28

lateral geniculate nucleus

After leaving the eye via the optic nerve, axons from both eyes will meet up at the optic chiasm where some will cross. From there, the axons terminate in the lateral geniculate nucleus (LGN) of the thalamus.

Question 29

Reduction of activity in one neuron by activity in neighboring neurons

Answer 29

Lateral inhibition

Question 30

Scott is looking at a series of grayscale bars. While he stares at a darker bar, it seems as if the border with a lighter bar seems “highlighted.” What could explain why he is seeing this visual effect?
a. Lateral inhibition
b. Opponent inhibition
c. Lateral summation
d. Bipolar excitation

Answer 30

Lateral inhibition

Lateral inhibition is an optical illusion created when activity in one neuron reduces the activity in neighboring neurons. This allows for us to clearly see edges.

Question 31

Which type of ganglion cells are distributed evenly throughout the retina and have relatively large cell bodies and receptive fields?
a. Parvocellular
b. Koniocellular
c. Leiocellular
d. Magnocellular

Answer 31

Magnocellular

Magnocellular neurons have larger cell bodies and receptive fields. They are distributed fairly evenly throughout the retina as opposed to parvocellular neurons that have small cell bodies and receptive fields.

Question 32

Elsa has had damage to area V1. As such, she may experience ____, the ability to respond in limited ways to visual information without perceiving it consciously.
a. synesthesia
b. visual agnosia
c. blindsight
d. central blindness

Answer 32

Blindsight

Damage to the primary visual cortex, called V1, can result in a surprising phenomenon called blindsight. In this case, Elsa has the ability to respond in a limited manner to visual information even though she cannot perceive it consciously (for example, reaching for an object that she cannot “see”). She is unaware of the visual input due to the damage.

Question 33

Which type of visual cortex cell responds equally to stimuli throughout a large receptive field?
a. Simple
b. Complex
c. Hypercomplex
d. End-stopped

Answer 33

Complex

Complex cells, located in V1 and V2, have large receptive fields and do not respond to the exact location of a stimulus. Most respond to stimuli in a particular orientation or that move in a specific direction.

Question 34

Terrance is an infant who was born with congenital cataracts. If the cataracts are not removed until childhood, what are the likely effects?
a. His visual recognition will remain permanently impaired.
b. His depth perception will rapidly improve.
c. His motion and depth perception will remain permanently impaired.
d. Virtually all aspects of vision will improve slowly with intensive training.

Answer 34

His motion and depth perception will remain permanently impaired

Although Terrance will likely regain some ability to recognize objects as well as hand–eye coordination, he will probably always have trouble with motion and depth perception. He might also have long-term issues with visual acuity.

Question 35

Mitsuko is holding an object that he can see is an apple because of the ventral pathway or stream through the temporal cortex. This path is also called the ____ pathway, because it is specialized for identifying and recognizing objects.
a. what
b. when
c. how
d. where

Answer 35

what

The ventral pathway through the temporal cortex allowed Mitsuko to identify the object as an apple. His dorsal pathway (“where”) allowed him to recognize that it had been sitting on the table before he picked it up with his left hand.

Question 36

Which part of the facial recognition system responds strongly to a face viewed from any angle, as well as line drawings and anything else that looks like a face?
a. Amygdala
b. Inferior occipital cortex
c. Fusiform gyrus
d. Medial temporal cortex

Answer 36

Fusiform gyrus

It is hypothesized that facial and body recognition are so important that we developed specific areas of cortical processing just for faces and bodies. The fusiform gyrus specifically responds to pictures of faces. Similarly, other areas nearby respond only to bodies, and so on.

Question 37

Oliver has been diagnosed with prosopagnosia. What is his main symptom?
a. He cannot see color.
b. He cannot experience depth perception.
c. He cannot recognize faces.
d. He cannot see at all.

Answer 37

He cannot recognize faces

Prosopagnosia is associated with damage to (or underdevelopment of) the fusiform gyrus. It results in a person being unable to recognize faces. Dr. Oliver Sacks (a famous writer about neurological problems) has been diagnosed with this disorder.

Question 38

Cells in the ____ respond selectively when something moves at a particular speed in a particular direction.
a. amygdala
b. inferior occipital cortex
c. fusiform gyrus
d. medial temporal cortex

Answer 38

Medial temporal cortex

Cells in the medial temporal cortex (also called V5) respond to objects that move at specific speeds and in specific directions. They can also detect acceleration and deceleration.

Question 39

What is colour constancy?

Answer 39

ability to recognize colors despite changes in lighting

Question 40

What is a type of cell that receives input from receptors and delivers inhibitory input to bipolar cells

Answer 40

Horizontal cell

Question 41

A ____ is the thalamic nucleus that receives incoming visual information

Answer 41

lateral geniculate nucleus

Question 42

What is the area in visual space that excites or inhibits any neuron

Answer 42

receptive field

Question 43

What is a small cell body with small receptive field in or near the fovea

Answer 43

parvocellular neuron

Question 44

The______ is a large cell body with a large receptive field that is distributed evenly throughout the retina

Answer 44

Magnocellular neuron

Question 45

The ______ is the area responsible for the first stage of visual processing

Answer 45

Primary Visual Cortex (V1)

Question 46

The ____ is the thalamic nucleus that receives incoming visual information

Answer 46

lateral geniculate nucleus

Question 47

What was Ibn al-Haytham’s evidence that we see only because light enters the eyes, not by sending out sight rays?

Answer 47

First, you can see distant objects such as stars far faster than we could imagine any sight rays reaching them. Second, when light strikes an object, we see only the light rays that reflect off the object and into the eyes.

Question 48

If someone electrically stimulated the auditory receptors in your ear, what would you perceive?

Answer 48

Because of the law of specific nerve energies, you would perceive it as sound, not as shock. (Of course, a strong enough shock might spread far enough to excite pain receptors also.)

Question 49

If it were possible to flip your entire brain upside down, without breaking any of the connections to sense organs or muscles, what would happen to your perceptions of what you see, hear, and so forth?

Answer 49

Your perceptions would not change. The way visual or auditory information is coded in the brain does not depend on the physical location within the brain. Seeing something as “on top” or “to the left” depends on which neurons are active but does not depend on the physical location of those neurons.

Question 50

What makes the blind spot of the retina blind?

Answer 50

The blind spot has no receptors because it is occupied by exiting axons and blood vessels.

Question 51

You sometimes find that you can see a faint star on a dark night better if you look slightly to the side of the star instead of straight at it. Why?

Answer 51

If you look slightly to the side, the light falls on an area of the retina with more rods and more convergence of input.

Question 52

If you found a species with a high ratio of cones to rods in its retina, what would you predict about its way of life?

Answer 52

We should expect this species to be highly active during the day and seldom active at night.

Question 53

According to the opponent-process theory, under what circumstance would you perceive a white object as blue?

Answer 53

If you stared at a bright yellow object for a minute or so and then looked at a white object, it would appear blue.

Question 54

Where does the optic nerve start and where does it end?

Answer 54

It starts with the ganglion cells in the retina. Most of its axons go to the lateral geniculate nucleus of the thalamus, but some go to the hypothalamus and superior colliculus.

Question 55

When light strikes a receptor, does the receptor excite or inhibit the bipolar cells? What effect does it have on horizontal cells? What effect does the horizontal cell have on bipolar cells?

Answer 55

The receptor excites both the bipolar cells and the horizontal cell. The horizontal cell inhibits the same bipolar cell that was excited plus additional bipolar cells in the surround.

Question 56

If light strikes only one receptor, what is the net effect (excitatory or inhibitory) on the nearest bipolar cell that is directly connected to that receptor? What is the effect on bipolar cells to the sides? What causes that effect?

Answer 56

It produces more excitation than inhibition for the nearest bipolar cell. For surrounding bipolar cells, it produces only inhibition. The reason is that the receptor excites a horizontal cell, which inhibits all bipolar cells in

Question 57

As we progress from bipolar cells to ganglion cells to later cells in the visual system, are receptive fields ordinarily larger, smaller, or the same size? Why?

Answer 57

They become larger because each cell’s receptive field is made by inputs converging at an earlier level

Question 58

What are the differences between the parvocellular and magnocellular systems?

Answer 58

Neurons of the parvocellular system have small cell bodies with small receptive fields, are located mostly in and near the fovea, and are specialized for detailed and color vision. Neurons of the magnocellular system have large cell bodies with large receptive fields, are located in all parts of the retina, and are specialized for perception of large patterns and movement.