Exam
Name___________________________________
 
ESSAY.  Write your answer in the space provided or on a separate sheet of paper. 
1) 

Explain the concept of a receptive field in the visual system and provide an example of this concept for a ganglion cell within the cat retina. 

 
2) 

Compare the anatomy and function of the dorsal and ventral streams. 

 
3) 

Delineate the structure and functions of the magnocellular and parvocellular visual systems. 

 
4) 

Explain the organization of neurons into modules in the striate cortex. Specify which neurons respond to color, orientation, spatial frequency, movement and retinal disparity. 

 
SHORT ANSWER.  Write the word or phrase that best completes each statement or answers the question. 
5) 

Describe how the physical dimensions of light correspond to the psychological dimensions of light. 

5)  

_____________ 

 
6) 

Compare and contrast the visual functions of rods and cones. 

6)  

_____________ 

 
7) 

Describe the primary visual pathway.  

7)  

_____________ 

 
8) 

Describe and explain the significance of the phenomenon of blindsight for visual perception.  

8)  

_____________ 

 
9) 

Define and explain what is meant by agnosia. 

9)  

_____________ 

 
10) 

Explain the notion that neurons in striate cortex function as feature detectors. 

10)  

_____________ 

 
TRUE/FALSE.  Write 'T' if the statement is true and 'F' if the statement is false. 
11) 

The wavelength of light determines the psychological dimension of hue. 

11) 

______ 

 
12) 

The fovea contains of an equal mixture of cones and rods. 

12) 

______ 

 
13) 

Sharp edges and fine detail contain low- spatial frequencies.  

13) 

______ 

 
14) 

Blindsight suggests that visual information that is not consciously perceived can control movements. 

14) 

______ 

 
15) 

The determination of the "what" of an object is a function of the dorsal visual stream. 

15) 

______ 

 
16) 

People with visual agnosias have normal acuity but are unable to recognize objects. 

16) 

______ 

 
MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question. 
17) 

Which of the following attributes corresponds to that of the dominant wavelength of light? 

17) 

______ 
A) 

threshold 

B) 

brightness 

C) 

saturation 

D) 

contrast 

E) 

hue 

 
18) 

The intensity of a light is also known as its 

18) 

______ 
A) 

hue. 
B) 

color. 
C) 

saturation. 
D) 

brightness. 
E) 

threshold. 

 
19) 

Which of the following attributes corresponds to the relative purity of a light stimulus? 

19) 

______ 
A) 

threshold 

B) 

saturation 

C) 

contrast 

D) 

brightness 

E) 

hue 

 
20) 

If a light stimulus that contains an equal number of all wavelengths is presented to humans, they will report a perception of 

20) 

______ 
A) 

a rainbow of colors. 
B) 

a fuzzy set of alternating black and white bars. 
C) 

white. 
D) 

mostly purple. 
E) 

a black color. 

 
21) 

Variation in the ________  of a light will result in variation in the perception of  ________ . 

21) 

______ 
A) 

saturation; brightness 
B) 

wavelength;  saturation 
C) 

wavelength; brightness 
D) 

intensity;  purity 
E) 

wavelength; hue 

 
22) 

Hue is to wavelength as saturation is to 

22) 

______ 
A) 

purity. 
B) 

brightness. 
C) 

intensity. 
D) 

concentration. 
E) 

threshold. 

 
23) 

The bony cavities that contain the eyes are the 

23) 

______ 
A) 

optic ossicles. 
B) 

optic disks. 
C) 

optic sinuses. 
D) 

conjunctivae. 
E) 

orbits. 

 
24) 

The amount of light entering the eye is regulated by the size of the 

24) 

______ 
A) 

optic orbits. 
B) 

sclera. 
C) 

pupil. 
D) 

lens. 
E) 

conjunctiva. 

 
25) 

The process of accommodation involves 

25) 

______ 
A) 

contraction of the ciliary muscles to dilate the pupil. 
B) 

the lens becoming more rounded to focus on near objects. 
C) 

contraction of the ciliary muscles to constrict the pupil. 
D) 

the lens becoming smaller as one ages. 
E) 

hardening of the lens as one ages. 

 
26) 

Collectively, the rods and cones are known as 

26) 

______ 
A) 

ganglion cells. 
B) 

vitreous humor. 
C) 

photoreceptors. 
D) 

the hemiretina. 
E) 

the fovea. 

 
27) 

A unique feature of the fovea is that it 

27) 

______ 
A) 

contains mostly rods. 
B) 

mediates vision in dim light. 
C) 

is devoid of photoreceptors. 
D) 

has very poor acuity. 
E) 

contains mostly cone photoreceptors. 

 
28) 

The optic disk is the location on the retina 

28) 

______ 
A) 

where the rods are most densely packed. 
B) 

where the cones are most densely packed. 
C) 

at which neural signals begin to diverge laterally. 
D) 

where axons leave the eye and join the optic nerve. 
E) 

that has the best visual acuity. 

 
29) 

The reason for a "blind spot" in the visual field is that  

29) 

______ 
A) 

the lens cannot focus all of the visual field onto the retina. 
B) 

retinal cells die with age and overuse, resulting in blind spots. 
C) 

blood vessels collect together and enter the eye at the blind spot. 
D) 

rods are less sensitive to light than are cones. 
E) 

there are no photoreceptors in the retina where the axons exit the eye. 

 
30) 

Visual information from the retina is carried by ________  to the ________ . 

30) 

______ 
A) 

ganglion cell axons;  thalamic medial geniculate nucleus 
B) 

ganglion cell axons;  striate cortex 
C) 

axons from bipolar cells;  thalamic medial geniculate nucleus 
D) 

short axon fibers;  optic chiasma 
E) 

ganglion cell axons;  thalamic dorsal lateral geniculate nucleus 

 
31) 

The manner in which visual information is carried from the retina to the cortex results in 

31) 

______ 
A) 

information from the nasal ganglion cells projecting to the ipsilateral hemisphere. 
B) 

information from one side of the visual field being transmitted to the opposite hemisphere. 
C) 

the decussation of all visual information through the optic chiasma. 
D) 

visual information remaining on the same side of the brain from retina to cortex. 
E) 

information from the temporal ganglion cells projecting to the opposite hemisphere. 

 
32) 

Which of the visual pathways below are important for the synchronization of activity to light-dark cycle? 

32) 

______ 
A) 

retino-geniculate-cortical pathways 
B) 

retino-hypothalamic pathways 
C) 

retino-pretectal pathways 
D) 

retino-spinal pathways 
E) 

retino-cerebellar pathways 

 
33) 

Select the correct sequence for processing of information in the primary visual pathway. 

33) 

______ 
A) 

Retina ->  striate cortex ->  extrastriate cortex -> inferior temporal cortex 
B) 

DLG->   frontal cortex -> amygdala -> extrastriate cortex 
C) 

Retina ->  DLG ->  inferior temporal cortex ->  amygdala 
D) 

DLG ->  retina ->  striate cortex ->  primary visual cortex 
E) 

Retina - > dorsal lateral geniculate  (DLG) -> striate cortex 

 
34) 

A microelectrode is inserted into a neuron within the primate visual system.  Various stimuli are presented to the eyes and changes in firing rate are recorded from this visual system neuron.  The part of the visual field to which a neuron responds is termed the 

34) 

______ 
A) 

striate response field. 
B) 

magnocellular visual system. 
C) 

receptive field. 
D) 

parvocellular visual system. 
E) 

tuning curve. 

 
35) 

Which of the following is an explanation for the higher acuity of the visual system at the fovea, relative to the periphery of the retina? 

35) 

______ 
A) 

Peripheral photoreceptors are more likely to be damaged by prolonged light exposure. 
B) 

A foveal ganglion cell may receive information from a single photoreceptor, whereas a peripheral ganglion cell may receive information from multiple photoreceptors. 
C) 

Peripheral photoreceptors are more isolated from bipolar cells and thus require greater activation in order to provoke a visual response. 
D) 

The fovea contains only rods which are directly connected to the ganglion cells. 
E) 

The foveal photoreceptor cells contain more photopigment per cell. 

 
36) 

The fact that we experience negative afterimages is taken as support for the  

36) 

______ 
A) 

idea that the visual system performs an algebraic summation of lights to generate a color perception. 
B) 

notion that the retina contains three types of photopigments. 
C) 

importance of color mixing in the visual system. 
D) 

trichromatic theory of color vision. 
E) 

opponent-process theory of color vision. 

 
37) 

In thinking of the pathways taken by visual information within the association cortex, the dorsal stream projects to________  and is involved in ________ . 

37) 

______ 
A) 

parietal association cortex;  the analysis of where an object is located in space 
B) 

inferior temporal cortex;  the analysis of where an object is located in space 
C) 

parietal association cortex;  the analysis of object identity 
D) 

temporal association cortex;  object form 
E) 

primary motor cortex;  object texture 

 
38) 

In thinking of the pathways taken by visual information within the association cortex, the ventral stream projects to ________  and is involved in ________ . 

38) 

______ 
A) 

temporal association cortex;  object color 
B) 

inferior temporal cortex;  deciding on the "what" of an object 
C) 

parietal association cortex;  the analysis of object identity 
D) 

primary motor cortex;  object texture 
E) 

parietal association cortex;  the analysis of "where" an object is located in space 

 
39) 

The inability to perceive or identify a stimulus via a particular modality is 

39) 

______ 
A) 

aphagia. 
B) 

agnosia. 
C) 

amnesia. 
D) 

prosopagnosia. 
E) 

insomnia. 

 
40) 

Extensive experience with different types of objects leads to improved object recognition which may reflect activation of the  

40) 

______ 
A) 

corpus callosum. 
B) 

fusiform face area. 
C) 

temporal cortex. 
D) 

dorsal extrastriate cortex. 
E) 

amygdala. 

 
41) 

Tasks that involve identification of an object would be expected to activate neurons of the ________  , while tasks that identify the location of an object would activate the ________ . 

41) 

______ 
A) 

 dorsal stream;  ventral stream 
B) 

area V5;  area V1 
C) 

ventral stream;  dorsal stream 
D) 

parietal cortex;  frontal cortex 
E) 

frontal cortex;  parietal cortex 

 
42) 

Research  by Goodale and colleagues indicates that the primary function of the dorsal stream of the visual cortex is to 

42) 

______ 
A) 

perceive spatial locations. 
B) 

track object movements. 
C) 

identify the form of an object. 
D) 

serve as feedback to guide actions. 
E) 

B and D are correct. 

 
1) 

Ganglion cells are the first cells in the visual system to show action potentials (APs) and it is possible to record the number of APs per unit time in a conscious animal while stimulating the retina with various lights.  A receptive field is that portion of the visual field of the organism that responds to a light with a change in AP firing rate (increase/decrease).  Ganglion cells in the cat show circular receptive fields. In some instances, the circular center responds with an increased firing rate when light is shown on the retina (ON response).  Light shown on a ring around the center of such a cell would decrease the firing rate of the cell (OFF response). 

2) 

Visual information from primary visual cortex is passed through a series of extrastriate cortex regions that modulates and integrates the information.  From area V2, some signals ascend in a dorsal stream to visual association parietal cortex.  The dorsal stream is involved in the analysis of spatial location.  Other signals diverge from area V2 in a ventral stream that reaches the inferior temporal cortex.  The ventral stream is involved in the perception of form. 

3) 

The lateral geniculate nucleus of the thalamus (LGN) is organized into six layers. The inner 2 layers contain large cells (magnocellular), while the outer 4 layers are comprised of small cells.  The magnocellular layers project to portions of the striate cortex that mediate visual processes other than color (e.g. form, movement, and depth).  The parvocellular layers are involved in the perception of color and fine detail.  

4) 

Striate cortex is organized into about 2500 modules, each containing about 150,000 neurons.  Each module has two segments that surround a central region, termed a blob, that contains cells that stain positively for cytochrome oxidase.  Cells within the blob receive information about color and low spatial frequencies.  Cells outside the blob are sensitive to different orientations, movement, spatial frequency, and texture, but not color.  Each neuron in the module receives information from the same region of the visual field. 

5) 

Wavelength of light refers to the distance between successive light wave peaks and determines the hue (perceived color) of light.  The intensity of light corresponds to the psychological dimensions of brightness.  Finally, purity refers to whether a light contains one or more wavelengths and this corresponds to the dimension of color saturation. 

6) 

The retina of the eye contains the photoreceptors that transduce light.  Rods are more common than are cones, which predominate within the central region of retina (the fovea).  Color vision is mediated by cones.  The ability to resolve fine detail is also a function of cones within the fovea.  Rods can function in low light conditions.  

7) 

Cells in the retina project through the optic chiasm to terminate in the dorsal lateral geniculate thalamic nucleus (LGN) and from there traverse to the striate cortex.   

8) 

Damage to the primary visual cortex damages a major source of visual input, but does eliminate all sources of visual input.  Such persons are unable to see in the affected visual field, but can reach for and grasp an object that is placed in the "blind" visual field.  This suggests that activation of the retina can produce a signal that can guide movements, even though these stimuli do not generate a conscious perception. 

9) 

Association cortex receives multiple streams of sensory information, which allows a human to use multiple modes to identify a stimulus.  Your mother, for example, has a unique facial pattern, hair color, tone of voice, and odor.  Damage to the association cortex can make it difficult for a person to recognize a stimulus, even though the person can still sense the stimulus. 

10) 

Cells in the striate cortex integrate information from a variety of visual cells in such a way that a cell may respond to visual stimuli that are more complicated than that of ganglion cells in the retina.  An annular receptive field for each of a set of ganglion cells may report to a cell in the striate cortex in such a way that a bar of light that stimulates the center of each ganglion cell receptive field causing the striate cell to fire.  Stimuli that do not precisely stimulate the center fields of an array of ganglion cells would not stimulate the striate cortex cell.  Different features (line, arc, circle) could be built up from different converging patterns to the striate cortex.