08. LGNV1

Question 1

What are the types of layers in the LGN? How many layers are there?

Answer 1

Layers 1 & 2 are MAGNO cellular layers
Layers 3-6 are PARVO cellular layers

Question 2

Which type of cells belong in what layer?

Answer 2

Midget –> Parvo
Parasol –> Magno

(Ps and Ms are switched)

Question 3

Activity in the LGN is dependent on what? (from the brain…)

Answer 3

Attention!
- this cannot happen in the retina bc the retina doesn’t receive any signals from the brain

Question 4

What distinct information is maintained (separate) throughout the LGN?

Answer 4

• R or L side of visual field
• midget vs parasol cells
• Relative location/order of objects in visual field
  –> triangle, square, star, etc

Question 5

The PARVO layer is important to perceive what kinds of information?

Answer 5

• Color
• Food

Question 6

The MAGNO layer is important to perceive what kinds of information?

Answer 6

• movement
• flicker

Question 7

Does perception happen in the LGN?

Answer 7

No, its just a pathway

Question 8

What does retinotopic mapping mean?

Answer 8

the point-by-point representation of the retinal surface in another structure in the visual system (ex. LGN, V1, etc)

Question 9

What does retinotopic mapping tell us?

Answer 9

the location of neural activity provides information about the location of the stimulus (and the region of retina that’s being stimulated)

• IE –> we know spatial relationship

Question 10

Cortical magnification def?

Answer 10

• More space in the brain is allotted to stuff that is close to the fovea
• magnifies the fovea

Question 11

What kind of structure/organization is there in V1?

Answer 11

COLUMNAR organization

Question 12

Ocular dominance columns means…?

Answer 12

• L/R eye signals are maintained/separated in V1 through columns

Question 13

Orientation columns means…?

Answer 13

• cells with preferred orientations are organized in columns systematically
• cells in a column have the same orientation, adjacent columns are similar
• location of activity gives us info on the orientation of stimulus

Question 14

Location columns means…?

Answer 14

• receptive fields on retina organized systematically in columns
• same column –> roughly same spot on retina
• adjacent columns –> close by / slightly diff
• loc. of neural act. tells us about loc. of stimulus