Download Study Guide 3

Psych 333
Test Yourself: Study Guide 3
VISUAL SYSTEM
1. What is light? How can light be characterized in physical terms?
2. What is the difference between white light and colored light?
3. What is the difference between mixing wavelengths of light and pigments in terms of what
colors we perceive?
4. What happens to light when it impinges upon objects in the environment?
5. Draw a diagram of the eye and label its main parts.
6. Name the two types of photoreceptor cells in the eye. What do they have in common? How do
they differ?
7. Only one process in vision actually involves light. What is it?
8. What parts of the eye are responsible for focusing light on the retina? How does this process
work?
9. What is a visual receptive field?
10. What is the fovea?
11. What is the blind spot, and why do you not see it normally?
12. Describe the process of visual transduction starting with light entering the eye and ending
with the response of a retinal ganglion cell.
13. What is lateral inhibition? Why is it important for visual perception?
14. What is meant by information processing? What types of processing occur in the retina?
15. Why does the release of glutamate from photoreceptors cause some bipolar cells to become
depolarized and others hyperpolarized?
16. Describe what types of stimuli would cause increased activity in a retinal ganglion cell with
an on-center, off-surround receptive field; what about a cell with an off-center, on-surround
field?
17. What causes nearsightedness (myopia?) What causes farsightedness (hyperopia)? How can
these defects be corrected?
18. What is the difference between bipolar cells and ganglion cells?
19. Which retinal cells provide lateral inhibitory connections?
20. How is increased sensitivity due to convergence of photoreceptor inputs related to acuity?
21. What is visual acuity? How could you measure it experimentally?
22. What is an after-image? Why do you see it?
23. Describe two ways in which processing in the retina might affect our visual perception.
24, Which cells in the retina produce action potentials? Which do not?
25. What is accommodation? How does it occur?
26. What is light-adaptation? What causes it, and why do we need it?
27. What is dark-adaptation? What causes it and why do we need it?
28. Why do we sometimes see things in a way that does not directly reflect the physical
characteristics of our environment? Give an example from the visual system.
29. The axons of the retinal ganglion cells form what nerve? Where does this information go?
30. What brain structures receive input directly from the retina? What is the function of each?
31. The lateral geniculate nucleus is a layered structure. Describe the way in which inputs to the
LGN are segregated according to layer.
32. What main classes of information are conveyed through the magnocellular pathways? ...the
parvocellular pathways?
33. What part of the brain receives the major projection from the lateral geniculate nucleus?
34. Describe three different functional classes of neurons found in primary visual cortex.
35. What is a cortical module? An orientation column? An ocular dominance column?
36. What is the difference between cortical "blobs" and interblob areas?
37. What feature(s) of the visual stimulus are most important for activating cells in V4?
Inferotemporal cortex? Area MT?
38. Describe at least one way in which experience influences the development of visual cortex.
39. Describe the trichromatic theory and the opponent-process theory of color vision. How
would each type of processing contribute to our perception of color?
40. How does a population code (across-fiber pattern) differ from a specificity (labeled-line)
code?
41. What is the most common cause of color blindness? Why is color blindness more common in
males than in females?
42. What is meant by color constancy? Object constancy?
43. What are the main principles (or "laws") of perceptual organization according to Gestalt
theory?
44. What are some cues that would allow you to separate a figure from its background?
45. According to feature integration theory, what stages of processing are hypothesized to occur?
What happens during each stage?
46. How does feature integration theory differ from the theory of recognition by components?
47. What is meant by spatial frequency? How are spatial frequency gratings used to study visual
perception?
48. What are the cues we use to perceive depth in the visual field? Which ones could you use if
you only had one eye?
49. What is meant by stereopsis? How does it occur?
50. What is apparent (stroboscopic) movement? Why does it occur?
51. How could a neural circuit that includes delay-lines and coincidence detector cells lead to
direction selective responses?
52. What is optic flow and why is it important for visual perception?