Copyright ©Mark Nelson, 2002. All rights reserved.
Chapter 11: The Visual System
What you need to know

(exam questions will be a drawn from this subset of material)

What are two types of photoreceptors are found in the vertebrate retina? How do they differ?   (p. 255-256)

Where does transduction take place in the photoreceptor cell?  (p. 256)

What is the name of the photopigment in vertebrate rods?  (p. 256)

What is the dark current? How does it affect the resting membrane potential of a photoreceptor in the dark? (p. 257)

How does the membrane potential of a vertebrate photoreceptor change when activated by light?  (p. 257)

What are the key steps in the phototransduction process?  (p. 257)

What is the role of photoreceptor adaptation?  (p. 258-259)

What is one of the cellular mechanisms involved in photoreceptor adaptation?  (p. 259)
What are the five main cell types of the vertebrate retina?  (p. 259-261)

Which cell types can generate action potentials?  (p. 261)

What are the output cells of the retina, i.e., what cell type sends sensory axons to the CNS?  (p.260-261)

What's connected to what in the retina?  (p. 260-261)

Which way do the photoreceptor cells "point" in the vertebrate retina?  (p.260)

How do the ganglion cell axons exit they eyeball?  (p. 260; Fig. 11-7)

What sort of receptive field organization do bipolar cells have?  (p. 261-264)

What cell type is responsible for creating the "surround" of the bipolar cell's receptive field?  (p. 261-264)

Does an on-center bipolar cell depolarize or hyperpolarize when the center of it's receptive field is stimulated with light?  (p. 262)

What are the response properties of retinal ganglion cells to spots of light of various sizes and positions?  (p. 265)

What are the differences between X and Y type ganglion cells in the cat visual system?  (p. 264-265)

What are the key difference between serial and parallel processing?  (p.267-268)

Where do visual signals go after they leave the retina?  (p. 268-269)

What sort of receptive field properties are found in LGN neurons?  (p. 269)

What is the functional role of the LGN?  (p. 269)

What is the next step in the visual processing pathway?  (p. 269-270)

What is the difference between simple cell and complex cell response properties?  (p.270-271)

How is the visual cortex organized?  (p. 273-276)

Which  invertebrates have single-lens eyes similar to those found in vertebrates? Do these animals have a "blind spot"? (p. 278-279)

What are the individual units that make up an insect compound eye?  (p. 280)