the attending brain

Question 1

Outline the differences between retiocentric space, egocentric space and allocentric space.

Answer 1

Space in the brain exists in various forms, including locations on sensory surfaces like the retina (retinocentric space), the location of objects relative to the body (egocentric space), and the location of objects relative to each other (allocentric space).

Question 2

What is attention, and how does it work?

Answer 2

Attention is the process of selecting certain information for further processing while discarding other information. It operates based on the relevance or importance of information to current goals and tends to be directed to locations in space.

Question 3

Describe the spotlight metaphor of attention.

Answer 3

The spotlight metaphor suggests that attention can move from one location to another, zoom in or out, and may not necessarily align with eye fixation. It highlights the limited capacity of attention, where not everything is illuminated at once.

Question 4

What controls the spotlight of attention?

Answer 4

The spotlight of attention can be controlled exogenously by external stimuli (bottom up) or endogenously through internal processes such as a target you are looking for (top down)

Question 5

Outline Posner’s study into Inhibition of Return (IOR)

Answer 5

Found a slowing of speed of processing going back to a previously attended location after a delay longer than 300ms
Exogenous control mechanism - we have already looked at it, so it feels unnatural to go back

Question 6

Explain the Feature Integration Theory (FIT) and its implications for visual search.

Answer 6

FIT proposes that perceptual features are encoded in parallel and prior to attention. If an object has a unique feature, it can be detected without attention (pops out, no matter how many targets), while objects sharing features require attention for identification, leading to a serial search process.
FITS proposes that attention selects perceptual objects and binds different features of those objects to make a reportable experience .

Question 7

Where in the brain does attention and spatial processing primarily occur?

Answer 7

Visual info through occipital lobes and then…
WHERE - DORSAL PATHWAY
Reaches parietal lobes - processes info about where items are located and how they might be acted on, guiding movements such as grasping
WHAT - VENTRAL PATHWAY
temporal lobes - object perception and memory, recognition of objects
HOW
Parietal lobes also bring together different types of spatial representation that are needed for action (e.g. integrating visual space with body space)

Question 8

Why might we have a leftward spatial bias? What study is there to support this?

Answer 8

hemispheric asymmetry of parietal lobes
right contains a richer representation than left, meaning we have a greater specialization of right parietal lobe means that we all have a tendency to attend to left side of space (pseudoneglect)
seen in study where bar with darkness on left side is assessed to be darker

Question 9

What is neglect, and what are its characteristics?

Answer 9

Neglect is a condition where patients fail to attend to stimuli on the opposite side of space to their lesion, most commonly following a stroke to the right hemisphere. Characteristics include line bisection errors, neglect in daily activities like dressing or eating, and deficits in various tasks involving spatial attention.

Question 10

Name the different types of neglect.

Answer 10

perceptual vs. representational neglect
neglect for near vs. far space
personal vs. peripersonal space
within objects vs. between objects

Question 11

Explain how neglect patients perceive stimuli in their neglected field despite claiming not to be aware of them. Give an example of a study which shows this.

Answer 11

Neglect patients still activate visual regions in the occipital lobes for neglected stimuli, which can be detected if attention is cued to that area. They may also process information unconsciously, as seen in studies where neglected information influences decision-making.
For example, the burning house study.

Question 12

Outline perceptual vs. representational neglect. What are the associated brain regions?

Answer 12

perceptual neglect = neglecting one side of space
representational neglect = neglecting one side of space in memories
Often occurs due to damage to the RH, causing left-side neglect

Question 13

Outline near vs. far space neglect. What are the associated brain regions?

Answer 13

near space = difficulty attending to and processing stimuli in the space that is within arm’s reach
far space = difficulties attending to stimuli in the space beyond arm’s reach.
both associated with damage to the parietal lobes (spatial processing)

Question 14

Outline Berti and Frassinetti’s study into near vs far space neglect

Answer 14

When far space neglect patients used the long stick to perform the drawing task (e.g clock or house), they tended to include a larger portion of the neglected side compared to when they used their hands or a regular drawing tool. This expansion of attended space suggests that the tool acted as an extension of their body, influencing their spatial representation.

Question 15

Outline personal vs peripersonal neglect.

Answer 15

personal = Personal neglect refers to a neglect of one’s own body parts or the space immediately surrounding one’s own body. May fail to attend to body parts on that side e.g shaving only one side. (body-space neglect)
peripersonal = neglect of the space surrounding the body, typically within arm’s reach. Patients may have difficulty attending to objects or events that occur on the affected side within this peripersonal space. (near-space neglect)

Question 16

Outline object vs between object neglect.

Answer 16

object = neglect of one side of individual objects, regardless of their location in space. Patients may fail to attend to or acknowledge the presence of one side of an object, resulting in incomplete visual processing or exploration of the object.
between object = neglect of the space between individual objects. Patients may fail to attend to or acknowledge the presence of objects located on the affected side of the space between other objects. This neglect can occur even when the individual objects themselves are attended to. (double dissociation with near-space neglect)

Question 17

Outline spatial vs object-based (allocentric) neglect. Discuss a study to support the conceptual difference between the two.

Answer 17

spatial - neglect to one side of space
object (allocentric) - refers to a deficit in attending to or perceiving one side of individual objects, regardless of their location in space.
Driver and Halligan - demonstrated that object-based neglect is axis based. Patients with this deficit could not attend to differences on the left side of an object, even if it was in the right side of space. Spatial neglect patients could do this.

Question 18

Describe the Piazza del Duomo experiment and its implications for representational neglect.

Answer 18

In the Piazza del Duomo experiment, patients were asked to describe a familiar place from different perspectives. They neglected to mention buildings on the left side when describing the scene from one perspective but remembered them when the perspective was reversed, demonstrating representational neglect.

Question 19

What is the role of the hippocampus in spatial processing?

Answer 19

The hippocampus codes allocentric space, which involves the spatial relationship between different landmarks, contributing to spatial memory and navigation.

Question 20

How does neglect manifest in reading tasks?

Answer 20

Neglect in reading can involve either object-based neglect, where patients make errors in reading individual letters, or space-based neglect, where they fail to read words on the left side of a page.

Question 21

Explain the concept of extinction in neglect patients.

Answer 21

Phenomenon of visual extinction suggests different perceptual representations are competing for attention (and visual awareness)
Extinction occurs when a neglected stimulus is presented simultaneously with another stimulus, causing the neglected stimulus to be “extinguished” from awareness (even if it is implicitly coded).

Question 22

How does prism adaptation therapy work in the rehabilitation of neglect?

Answer 22

Prism adaptation therapy involves wearing prism glasses that shift the visual field towards the neglected side, encouraging patients to attend to that side and gradually reducing neglect symptoms.

Question 23

Outline Dye et al’s study into the impact of video games on cognitive abilites.

Answer 23

Dye used TOVA is used to assess impulsivity and sustained attention by requiring participants to respond to target stimuli while withholding responses to non-target stimuli.
Participants were either videogame players or not videogame players.
Found that VGP were faster in both the sustained attention and impulsivity condition. Levels of accuracy were the same across both groups = enhanced attentional control in VGP

Question 24

What are the effects of video games on cognitive abilities, according to research?

Answer 24

Research suggests that action video game playing can improve various visual and cognitive skills, including attention, cognitive control, and multitasking.

Question 25

Describe the NeuroRacer game and its purpose in cognitive research.
What impacts did the game have on the participants?

Answer 25

The NeuroRacer game was developed to assess cognitive abilities in older adults and has been shown to improve cognitive control and multitasking skills through gameplay.
Found that after playing, older ppt were showing EEG patterns of 20y/o. Changes in preftontal cortex = improvement in executive functions and saw improved communication between brain areas.

Question 26

Describe the Visual Search Task mentioned in the lecture and how it relates to FIT.

Answer 26

In the Visual Search Task, participants are asked to locate a target (e.g., a blue T) among distractors. FIT explains that when the target differs from distractors in a single feature (C1 condition), it can be identified quickly due to parallel processing. However, when the target shares features with distractors (C2 condition), attention is needed to integrate features, leading to a serial search, aligning with FIT principles.

Question 27

What does FIT suggest about the role of attention in combining perceptual features into a complete representation?

Answer 27

FIT suggests that attention is crucial for combining perceptual features into a complete representation. While basic features are processed in parallel, attention is required to integrate these features into coherent objects, particularly when targets share features with distractors.

Question 28

How does neglect manifest in line bisection tasks, and what does it indicate about spatial perception in neglect patients?

Answer 28

Neglect patients tend to misplace the center of lines toward the right, underestimating the extent of the left side. This manifestation suggests a bias in spatial perception towards the ipsilesional (unaffected) side, indicating a deficit in attending to stimuli on the contralesional (neglected) side.

Question 29

Describe the concept of salience maps and their involvement in neglect, as proposed by Corbetta and Shulamn.

Answer 29

Salience maps are neural representations that encode the relative importance or significance of different stimuli in the environment. Corbetta and Shulamn proposed that dysfunction in the right posterior parietal cortex, containing salience maps, may lead to functional deactivation despite intact structure, contributing to neglect symptoms.

Question 30

Other than Driver’s study, outline three studies which show the difference between within object vs between object neglect (space-based).

Answer 30

Robertson ‘Finding A’ Study – neglected left side of both columns, even though the right side of the left column is closer to the left (neglected) space than the left side of the right column
Object-based neglect in reading - letter substitution errors in reading words and nonwords (e.g., Object-based neglect in reading - letter substitution errors in reading words and nonwords (e.g., reading “home” as “come”)
Space-based neglect in reading - read individual words correctly but fail to read whole words on the left of a page

Question 31

Which lesions/faulty mechanisms are neglect patients most commonly associated with?

Answer 31

Lesions:
Damage to right parietal lobe/parietal association cortex (more severe than left damage)
Faulty mechanisms:
o loss of neurons dedicated for representation of that space
o a failure to shift attention to that side
o some combination of the two

Question 32

Outline the role of the parietal lobes in spatial processing and attention.

Answer 32

Corbetta and Shulman’s Model (2002): Proposed two main attention-related circuits involving the parietal lobes:
Dorso-Dorsal Circuit: Involves the lateral intraparietal area (LIP), associated with attentional orienting within a salience map.
Ventral Circuit: Involves the right temporoparietal junction (TPJ), responsible for diverting attention away from its current focus.

Brain imaging studies of visual tasks:
Dorso-Dorsal Network: Involving LIP and eye fields, activated by endogenous cues and responsible for processing what is being looked at.
Ventro-Dorsal Network: Involving the temporal-parietal area and ventral frontal cortex, activated by exogenous cues and responsible for diverting attention away from the current cognitive task to another focus.