Functional Architecture of V1

Question 1

Types of cortical columns

Answer 1

Ocular dominance- brain organized based on eye input.
Orientation
wavelength
Maybe spatial frequency

Question 2

What is a cortical area

Answer 2

Homogenous pattern of connections. Similar neuron characteristics. Single retinotopic map.

Question 3

What happens to receptive field as electrodes pass through cortex?

Answer 3

See random scatter in receptive field position and some variation in size. But no overall tendency for the positions to change. No regular pattern.

Question 4

1 mm on the cortex produces a movement through the VF that is ____ the space occupied by the electrode.

Answer 4

half. ex: 10 mm electrode. Vf will be stimulated 5 mm away.

Question 5

Orientation of ocular dominance columns

Answer 5

Same eye vertical. Changes between R and L horizontal.

Most clear in layer 4C

Question 6

Orientation of orientation columns

Answer 6

Vertical is same orientation. Horizontal changes orientation progressively. Not seen in layer 4C- no orientation preference here.

Orientation pinwheels are at the center of OD columns.

Question 7

Hypercolumns

Answer 7

OD and OS ocular dominance columns together. Represent 180 degrees of orientation. Module size is constant throughout v1, but represents more VF area as it progresses from fovea to periphery.

Question 8

Cytochrome oxidase is an indicator of

Answer 8

energy consumption.

Question 9

Highest density of CO

Answer 9

Throughout layer 4C (M and K cell input) and layer 3 (blobs, koniocellular input)

Question 10

The cells inside blobs are responsive to

Answer 10

Wavelength. Color and low spatial frequency. Cells outside of blobs may not be responsive to wavelength.

Question 11

R/G vs Y/B blobs

Answer 11

RG outnumber YB by 3:1.

Question 12

Pathway of RG and Blue cones to the blobs

Answer 12

RG and blue cones both send info to ganglion cells.
LGN parvocellular cells send RG info to the blobs
LGN koniocellular cells send blue info to the blobs

Question 13

What is a module and how many blobs are in it?

Answer 13

a module is of constant size and contains R and L ocular dominance columns. 2 blobs.

Question 14

As one moves from V1 areas representing the fovea (top of the occipital lobe. Posterior) to those representing more peripheral portions of the VF (anterior V1) the size of modules _____ and the VF ____

Answer 14

module stays same size. 
VF increases.

Question 15

Moving from fovea to periphery.
Cortical mag ____
Inverse cortical mag ___

Answer 15

decreases

increases