Study Guide for Chapter 3

1.         What is the relative ratio of photoreceptors to retinal ganglion cells in the human visual system?

2.        What is single cell recording and for what is it used?

3.         You need to understand the concepts of resting potential and action potentials.  How do neurons communicate? If you need a review of this information, either see me or look it up in either an intro psych or biopsych text (I have plenty if you’d like to borrow one). Neural communication is the basis for this course, so you do have to have a basic understanding of it.

4.         What is a receptive field? How would you map out a receptive field? What is the shape of receptive fields in the retinal ganglion cells?

5.         What does it mean to give an “on response?” What is an “off response?”

6.         What is lateral inhibition?

7.         What type of information is gained because of the antagonistic arrangement of center-surround receptive fields?

8.         What is the sole function of horizontal cells? What is the end result of this function?

9.         What role do bipolar cells play in the process of vision?

10.       What do we know about amacrine cells?

11.       As you move farther from the fovea, how does the relative size of a receptive field change? What effect do you think this difference has on sensitivity and acuity? What does this difference tell us about the perception of object size?

12.       How many types of retinal ganglion cells are there? You should be able to compare the physiological properties of M, P, and K cells. What does “M” stand for? What about “P?” (You really don't need to know much about K RG cells.)

13.       What is the primary difference between brightness and lightness?

14.       What is a Hermann grid? How is it explained?

15.       What are Mach bands? How do you explain them?

16.       What is the difference between intensity and lightness?

17.       What is lightness contrast? What is lightness constancy? Under what condition does lightness constancy fail?

18.       What does it mean to say that there is a trade-off between sensitivity and acuity?

19.       How does the visual system minimize this trade-off? What is the scotopic system? What is the photopic system? What about mesopic vision?

20.       What do your authors mean when they say that “convergence is the enemy of resolution?”

21.       What does it mean to have 20-20 vision?

22.       What is dark adaptation? How or why does it occur? How would you obtain a dark adaptation curve? What would it look like and why?

23.       Read Box 3.7 on page 109. What are some of the important points to be gleaned from this box?