Major attentional systems and Disorders of attention

Question 1

Discuss the cueing task study by Posner (1980)

Answer 1

-ppts had to respond quicky to the picture of a light
- before the picture of the light they were presented with different cues e.g a neutral cue, central cue and peripheral cue

findings: valid cues had the fastest response times.

Question 1

what is covert attention

Answer 1

allowing the brain to attend to an object without moving eyes to the object

Question 2

Describe the voluntary/endogenous visual attention system proposed by Posner

Answer 2

• internal cause
• involved when central cues present (e.g arrow)
• goal directed

Question 3

Describe the involantary/exogenous visual attention system proposed by Posner

Answer 3

• external cause
• involved when peripheral cue is present (sudden noise e.g)
  -stimulus driven

Question 4

Describe the top down system proposed by corbetta and Shulman

Answer 4

• the brain network involved in the goal directed attentional system
• consists of a dorsal fronto parietal network

Question 5

Describe the bottom up system proposed by corbetta and shulman

Answer 5

• a stimulus driven attentional system
• provided a circuit breaking function- visual direction redirected from its current focus
• consists of right hemisphere ventral fronto-parietal network

Question 6

What did Corbetta and Shulman (2002) argue, in essence, when they carried out a meta-analysis of brain-imaging studies

Answer 6

• they argued that brain areas are more activated when ppts expect a stimulus that has not yet been presented from the dorsal attention network. AND. when individuals detect low frequency targets from the ventral attention network.

Question 7

Hahn et al. (2006) tested Corbetta and Shulman’s (2002) theory by comparing patterns of brain activation when top-down and bottom-up processes were required. What did they find?

Answer 7

• no overlap between the two processes
• the brain areas involved in each type of processing corresponded with corbetta and shulmans findings

Question 8

What are the strengths of corbetta and Shulman

Answer 8

• evidence for goal directed and stimulus driven systems
• causality
• Dissociations

Question 9

What are the limitations of corbetta and shulman

Answer 9

• dont know what brain areas do what
• dont know how goal directed and stimulus driven systems interact
• oversimplified

Question 10

Define the disorder of visual attention known as neglect

Answer 10

one half of the perceptual world is neglected to some degree and cannot be attended to as completley as normal

• problem with left visual feild and right hemisphere, e.g not shave groom or dress left side of there body
• patients unaware of there neglect

Question 11

What is space based/egocentric neglect

Answer 11

limited awareness of stimuli to the left side of visual feild

Question 12

what is object centered / allocentric neglect

Answer 12

lack of awareness of left side of objects

Question 13

what is extinction

Answer 13

failure to detect a stimulus presented to one visual feild (typically left) when another stimulus is simultaneosly presented to the other side

Question 14

Discuss the study by Vuilleumier et al on extinction

Answer 14

-IN PHASE 1 ppts with extiction were shown a moneky in LVF and a watch in RVF, memory test showed ppts had little memory on left side items.

• IN PHASE 2 a degraded pic was slowly reconstructed and ppts had to identify the item as soon as possible, results show facilitation even in left presented iteams not consciously seen.

Question 15

What was Riddoch et als study on how integration reduces competition

Answer 15

• objects used together (wine and bottle) and objects never used together (wine and ball)
• wine bottle and glass had 65% identification whilst wine bottle and ball had 40% identification
• extinction patients can reduce extinction when two stimuli can be combined together rather than competing with each other