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Flashcards in Problem 4 Deck (25)
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1

Spatial organization

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

2

In which way do the cortex and the retina correspond ?

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

3

Cortical magnification

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

4

Location columns/Ocular dominance columns

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

5

Orientation columns

Its cells respond best to a particular orientation

6

Hypercolumn

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

--> consists of 2 ocular dominance columns

7

Tiling

The combination of the separate columns to create a full perception

--> working together, they cover the entire visual field

8

Ablation

The destruction/ removal of tissue in the nervous system

9

Ventral Pathway
(What)

Pathway leading from striate cortex to the temporal lobe

--> responsible for determining an objects identity

( V1 / 2 / 3 / 5 )

10

Dorsal pathway
(Where + How)

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 )

11

Do the two pathways communicate ?

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

12

Feedback

Refers to the backward flow of information

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

13

Module

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

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

14

Lateral Geniculate Nucleus

A 6-layered structure that is part of the thalamus

--> there is one in each hemisphere

15

Magnocellular layer
(large)

Bottom 2 layers of the LGN

--> physically the largest one

16

Parvocellular layer
(petit)

Top 4 layers of the LGN

--> cells are physically smaller than the bottom 2

17

Koniocellular cell

Neuron located between the 2 major layers

18

What is the function of the LGN ?

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

19

Thalamic inhibition

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

20

Topographical mapping

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

21

Simple cells

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

22

Complex cells

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

23

Double dissociation

Helps determine whether two functions operate independently from one another

--> involves 2 people

24

Single dissociation

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

--> involves only one person

25

Behavior of person D.F

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