Problem 4

Question 1

Spatial organization

Answer 1

Refers to the way stimuli at specific locations in the environment are represented by activity at specific locations in the Nervous system

Question 2

In which way do the cortex and the retina correspond ?

Answer 2

Locations on the cortex correspond to locations in the retina

–> if a neuron is recorded at point A on the cortex, its receptive field will be located at point A on the retina

Question 3

Cortical magnification

Answer 3

Stimulation of the small area near the fovea activates a greater area on the cortex

–> there is a large representation of the fovea in the cortex which translates into better detail vision

Question 4

Location columns/Ocular dominance columns

Answer 4

Are located perpendicular (senkrecht) to the surface of the cortex

1. contain neurons that respond to all possible orientations (orientation columns)
2. neurons within the location columns have their receptive fields at the same location on the retina

Question 5

Orientation columns

Answer 5

Its cells respond best to a particular orientation

Question 6

Hypercolumn

Answer 6

Perceives information about all possible orientations that fall within a small area of the retina

–> consists of 2 ocular dominance columns

Question 7

Tiling

Answer 7

The combination of the separate columns to create a full perception

–> working together, they cover the entire visual field

Question 8

Ablation

Answer 8

The destruction/ removal of tissue in the nervous system

Question 9

Ventral Pathway

What

Answer 9

Pathway leading from striate cortex to the temporal lobe

–> responsible for determining an objects identity

( V1 / 2 / 3 / 5 )

Question 10

Dorsal pathway

Where + How

Answer 10

Pathway leading from the striate cortex to the parietal lobe

–> responsible for determining an objects location

–> provides information about how to direct action with regard to the object

( V1 / 2 / 4 )

Question 11

Do the two pathways communicate ?

Answer 11

Yes,

• -> they have connections
• -> their signals are reciprocal (flow goes up + down)

=> the properties of both pathways are established by 2 types of ganglion cells who then transmit signals to the LGN

Question 12

Feedback

Answer 12

Refers to the backward flow of information

–> provides information from higher centers that can influence the signals flowing into the system

Question 13

Module

Answer 13

Structure that is specialized to process information about a particular type of stimulus

ex.: fusiform face are, parahippocampal place area, extra striate body area

Question 14

Lateral Geniculate Nucleus

Answer 14

A 6-layered structure that is part of the thalamus

–> there is one in each hemisphere

Question 15

Magnocellular layer

large

Answer 15

Bottom 2 layers of the LGN

–> physically the largest one

Question 16

Parvocellular layer

petit

Answer 16

Top 4 layers of the LGN

–> cells are physically smaller than the bottom 2

Question 17

Koniocellular cell

Answer 17

Neuron located between the 2 major layers

Question 18

What is the function of the LGN ?

Answer 18

1. Location where various parts of the brain can modulate

–> explains why there are more feedback connections from the visual cortex to the brain

2. Both eyes have ipsilateral + contralateral connections with it
3. Ganglion cells synapse here
   - -> acts as a “relay station” on the way to the cortex

=> Retina –> LGN –> Cortex

Question 19

Thalamic inhibition

Answer 19

When the input from the retina reaches the LGN, the signal stops here, before reaching the cortex (short relay)

–> useful for when we sleep - we don’t wake up this way

Question 20

Topographical mapping

Answer 20

Refers to the orderly mapping of the LGN and visual cortex

–> two points that are close together in the retina are also close together in the LGN

Question 21

Simple cells

Answer 21

Cortical neurons whose receptive field has clearly defined excitatory + inhibitory regions

–> might only respond when light is presented in the center of the receptive field

Question 22

Complex cells

Answer 22

Cortical neurons whose receptive field does not have clearly defined excitatory + inhibitory regions

–> responds regardless of where the light is presented, as long as it is in the receptive field

Question 23

Double dissociation

Answer 23

Helps determine whether two functions operate independently from one another

–> involves 2 people

Question 24

Single dissociation

Answer 24

Allows one to infer that function X + Y are independent of each other

–> involves only one person

Question 25

Behavior of person D.F

Answer 25

Suffered damage to her ventral pathway from carbon monoxide poisoning

–> trouble orienting a card to match the orientation of the slot, but was able to do it when asked to ‘mail’ it

=> performed poorly in the static orientation-matching task but did well as soon as action was involved