# A quiz on the human visual system

1. Why are the decks of ships usually illuminated using red light at night?

• To reduce the amount of light pollution from the ship
• So that only one type of cone is used, leaving the others free for looking out
• So that the dark-adaption of the rods is affected as little as possible

• Because ships may not show any other colour lights
2. Blue cones are much less responsive than red- and green-sensitive ones. How does the brain handle this?

• The rods contribute to the blue response too
• The brain amplifies' the blue signal much more than the red and green ones

• There are more blue-sensitive cones in the fovea
• Sunlight is much more intense in the blue
3. Signals from the eye travel via the optic nerve to which of the following?

• laterate geniculate nucleus

• visual striate cortex
• V4
• V1
4. What type of cell is responsible for vision in low-light conditions?

• fovea
• retina
• rod

• cone
5. Where does the "where" or "how" pathway run?

• V2, V3, V4, V5
• V2, V4
• V2, V3
• V2, V5

6. Roughly, what is the range of wavelengths of visible light?

• 100--1000 nm
• 400--700 nm

• 0--100 nm
• 1000--5000 nm
7. What is "continuity" in the context of visual processing?

• filling in missing boundaries

• a continuous stream of pixels
• an analogue signal
• a derivative exists
8. What type of cell is responsible for colour vision?

• rod
• fovea
• cone

• retina
9. To which of the following do the cells in V1 respond to?

• motion
• orientation, edge
• orientation, edge, motion

• edge, motion
10. What is the fovea?'

• A depression in the retina which has many more cones than elsewhere on the retina

• The part of the eye that focuses light
• Where the optic nerve leaves the eye
• The part of the eye that controls how much light is admitted into the eye
11.