Week 3

Question 1

Two main visual streams

Answer 1

1. Focal vision
   - object identification
2. Ambient vision
   - motion

Question 2

Focal vision stream function?

Answer 2

• Conscious object identification
  
  • Central visual area
    What is it?

Question 3

Ambient vision stream function?

Answer 3

• Second visual system
  
  • Involves entire visual field
  • Non-conscious
  • Works in dim lighting conditions
  • Where is it?

Question 4

Define photoreceptor cells

Answer 4

Special cells in the eye’s retina that are responsible for converting light into signals that are sent to the brain.

Question 5

Define retina

Answer 5

photoreceptors and neurons arranged in a sheet at the back of the eye

Question 6

Rods function

Answer 6

Process Motion

Question 7

Cones function

Answer 7

Process Colour

Question 8

what are the 2 ganglion cell types, where are they located, and function

Answer 8

P cells (parvo)

- Near fovea 
- High acuity and colour vision 

M cells
- In periphery
Motion detection

Question 9

Ganglion cells run along inner surface of the retina and gather together to form the…….?

Answer 9

Optic nerve

Question 10

Function of retina cells

Answer 10

Involved in processing of visual information before it is transmitted to the brain

Question 11

what are the 3 visual fields

Answer 11

Binocular zone
- Area where both eyes can see
Left and right monocular zone
- Where either eye can only see

Question 12

optic nerve projects into what 3 structures

Answer 12

1. Superior colliculus
2. Lateral geniculate nucleus
3. Reticular formation

Question 13

Superior colliculus function

Answer 13

• Accommodation and light reflexes

- Coordinates eye-head reflexes

Question 14

6 layers of the lateral geniculate nucleus

Answer 14

• Ipsilateral - 2,3,5

- Contralateral - 1,4,6

Question 15

Function of layers 1 - 2

Answer 15

• Large cells
  
  • M cells input
  • Movement

Question 16

Function of layers 3 - 6

Answer 16

• Small cells
  
  • P cell input
    Acuity

Question 17

Lateral geniculate nucleus (LGN)

Answer 17

projects to occipital lobe

Question 18

Describe retina map

Answer 18

• Topographical order of retinal map and hence of the visual. Your information is swapped around, upside down and back to front (e.g. bottom right, is now top left)

Question 19

Define blob cells and their function

Answer 19

Cells for analysis of object colour

Question 20

Define hypercolumn

Answer 20

grouping of ocular dominance and orientation columns

Question 21

simple cells function

Answer 21

orientation and specific position

Question 22

complex cells function

Answer 22

specific orientation but any place in the visual field

Question 23

Hypercomplex cells function

Answer 23

responses to bars of specific length and width

Question 24

Define apraxia

Answer 24

• Individual elements of a task can be carried out
  
  • Patients understand what is required
  • But cannot perform movement task

Question 25

Define ideational apraxia

Answer 25

• Breakdown in ability to access the ‘ideas’ ‘memory representations’ for motor acts
  
  • Cannot pantomime use of object (pretend to brush teeth)
  • But can use actual object (will brush teeth with toothbrush)

Question 26

Define ideomotor apraxia

Answer 26

• Breakdown in translation of memory representations into motor commands
  
  • Inability to imitate what else is doing