Task 8 - Lesion Studies

Question 1

What are the most common sources of cortical lesions?

Answer 1

• Surgery
• Strokes
• Traumatic Injuries
• Tumors

Question 2

If a patient is impaired on task A but performs normal on task B, this is called a …

Answer 2

classical single dissociation

Question 3

What is the strong form of a single dissociation?

Answer 3

When the patient is impaired on two tasks but less on one.

Question 4

What is usually the conclusion from a single dissociation?

Answer 4

That the tasks use different cognitive modules.

Question 5

How does a task-resource artifact confound a lesion study?

Answer 5

When the two tasks require different amounts of resources from the same brain process, which is affected by the lesion, then a single dissociation might be wrongly concluded.

Question 6

When a single dissociation is observed due to suboptimal performance strategy of the participant on one task instead of his lesion being the reason, this is called …

Answer 6

Task-Demand Artifact

Question 7

How can a double dissociation be described in terms of single dissociations?

Answer 7

It is basically two single dissociations that have complementary effects between two people.

Question 8

What is the Fractionation Assumption of Lesion studies?

Answer 8

That damage to the anatomical brain can produce selective cognitive impairments.

Question 9

What is the Transparency Assumption of Lesion studies?

Answer 9

Lesions do not create new cognitive systems.

Question 10

What is the Universality Assumption of Lesion studies?

Answer 10

Cognitive systems across individuals are identical.

Question 11

Why is the transparency assumption less likely to be violated in adults than in children?

Answer 11

Because children’s brains are more plastic.

Question 12

What is syndrome research controversially not interested in?

Answer 12

Individual differences

Question 13

What is the main shortcoming of case studies?

Answer 13

Their low generalizability

Question 14

What is a counterargument against the low generalizability of case studies?

Answer 14

One might not be able to generalize from one case to another, but a single case can still inform about the validity of a theory.

Question 15

What is a reason that localizing the effect of a lesion might be difficult?

Answer 15

• Lesions are rarely clear-cut.
• Tumors might distort neighboring areas or cut off blood flow.
• Some neurons might also be inoperative even though they are not seen as destroyed on a scan.

Question 16

When lesions impair more distal neural activity by blocking pathways, this is called …

Answer 16

Diaschisis

Question 17

What are some important brain structures for attention?

Answer 17

• Superior Colliculus
• Pulvinar (Thalamus)
• Parietal Regions

Question 18

What does a double dissociation indicate?

Answer 18

That two functions are relatively independent.

Question 19

What is a limitation of single dissociations, that double dissociations improve on?

Answer 19

Single dissociation leaves open the possibility that the critical lesion produced its effect not because the area it disrupts is specifically involved in the particular function in question, but because that region of the brain is simply more important in some general sense.

Question 20

Why can’t lesions studies address the time-course of a process?

Answer 20

Because lesions are permanent

Question 21

What is the main advantage of Lesion studies over fMRI studies?

Answer 21

It offers causal inferences.

Question 22

How does Behrmann’s study (1994) contribute to the discussion of the neural correlates of visual imagery?

Answer 22

Previously, a single dissociation was found in that lesioned patients could recognize objects but not imagine them. In this study, the reverse was found for a patient with a lesion in the occipital lobe, hinting at a double dissociation between visual recognition and visual mental imagery.

Question 23

What dissociation suggests a hierarchical relationship between two cognitive functions?

Answer 23

Single

Question 24

That brain functions can be carried out in a distributed manner is a problem for the assumption of….

Answer 24

Modularity