perceptia a doua

Question 1

Why do we look at patients with brain lesions?

Answer 1

Because from a broken system, you can learn about how it worked before it was broken.

Question 2

What is the ventral stream?

Answer 2

The what stream

Question 3

What is the dorsal stream?

Answer 3

The where stream.

Question 4

What does V5 do?

Answer 4

It picks up movement.

Question 5

Where did patient D.F have damage?

Answer 5

He had damage to the what stream, which lead to visual agnosia. A patient with such damage need to be assessed to see that they have normal vision. When you give them a task to copy a picture they can draw the object. So they can draw the object but they can’t recognise what it is.

Question 6

What is visual agnosia?

Answer 6

Visual agnosia is a failure to recognise objects by sight, despite vision itself remaining intact. In other words, when you have damage to the what stream, but have an intact where stream.

Question 7

So what does damage to the what stream lead to?

Answer 7

Visual agnosia.

Question 8

What is dissociation?

Answer 8

When you can’t recognise objects visually, but could still guide actions towards objects by sight. You do not understand what you are seeing, but you can still unconsciously use the object.
For example, a patient with visual agnosia (damage to what=ventral stream) might not be able to recognise a letter box, but they are still able to use it and so slide a letter through the letter box.

Question 9

When what stream is impaired, is where stream also impaired?

Answer 9

No. Scans using fMRI revealed normal activation of dorsal (where) stream in patients with visual agnosia.

Question 10

What is optic ataxia?

Answer 10

Damage to the where stream (dorsal stream). Patient can recognise and tell you what an object is, but if you ask them to grab it, they don’t grab the object the way they should. The interaction with the object is impaired.

Question 11

So what does damage to the where stream lead to?

Answer 11

Optic ataxia.

Question 12

What is Gestalt Psychology?

Answer 12

Some laws of visual organisation.

Question 13

What is law of Pragnanz?

Answer 13

Reality is organised or reduced to the simplest form possible. The Olympic games symbol is seen as a series of circles.

Question 14

What is the law of proximity?

Answer 14

Things that are CLOSE together are grouped together.

Question 15

What is the law of similarity?

Answer 15

Things that are SIMILAR are grouped together.

Question 16

What is the law of good continuation?

Answer 16

If a line has a certain orientation before the junction, it is likely to carry that way afterwards.

Question 17

What is the law of closure?

Answer 17

If an object isn’t complete you still see it as complete.

Question 18

What is the Gestalt principle of common fate/motion?

Answer 18

If things move together, they are seen as belonging to one object/group.

Question 19

What was patient DF unable to perceive?

Answer 19

Good continuation.

Question 20

What is synaesthesia?

Answer 20

A joining of sensations that are normally experienced separately. E.g. when you see a colour, you have a taste in your mouth
Input in one modality leads to the experience of activity in another modality.

Question 21

What are the mechanisms for synaesthesia?

Answer 21

Neural: cross connections between regions that are usually not talking to each other
Psychological: you can make people believe they have it by putting them under hypnosis

Question 22

What is the modular view?

Answer 22

We do not have to effortfully re-recognise objects every time a feature varies e.g. a chair.
Particular brain areas are specialised for recognising different categories of objects like faces or houses.

Question 23

What is fusiform face area for?

Answer 23

Functionally specialised for recognising faces.

Question 24

What is the parahippocampal place area for?

Answer 24

Functionally specialised for recognising places.

Question 25

Where does modularisation come from?

Answer 25

May be predisposed: new born babies prefer to look at faces as soon as they are born.
May be developed over time: children develop modules as they go through life

Question 26

What is prosopagnosia?

Answer 26

Face blindness. People unable to recognise faces. But they can recognise people by voice.