Lecture 6- Attention & Neglect

Question 1

How did Posner et al. (1980) describe the function of attention?

Answer 1

Attention can be likened to a spotlight that enhances the efficiency of the detection of events within its beam.

Question 2

What is attention in the context of cognitive processes?

Answer 2

Attention is the process by which some stimuli are selected for privileged processing.

Question 3

Why does attention select certain stimuli over others?

Answer 3

The nervous system has a limited capacity and cannot process all things at all times, so stimuli compete for limited resources.

Question 4

What are the two roles that attention fulfills according to cognitive psychology?

Answer 4

Attention is both a process (orienting/selecting/gating) and a resource (capacity).

Question 5

What are four cognitive components of attention?

Answer 5

1. Arousal- generalized sense of arousal
2. Sustained attention- duration of focus, vigilance
3. Selective attention
4. Divided attention-Allocation of resources between different tasks

Question 6

What are three components of the working model of attention? (Posner)

Answer 6

1. Alertness: Maintains focus over time, directed by stimulus importance.
2. Re(Orienting): Shifts focus, comparable to moving a flashlight’s beam; neglect indicates a failure in shifting attention.
3. Executive: Mediating & monitoring interaction between top-down and bottom
   up processes

Question 7

What are the brain regions associated with the Alertness and Re(Orienting) component of the working model of attention?

Answer 7

1. Alertness: RAS, Superior colliculus, Right lateralized, frontal-parietal-thalamic network, dorsal attention system
2. Re(Orienting): Subcortical, frontal and parietal areas, ventral attention network

Question 8

What are the two main brain areas are associated with executive control of attention (in the working model of attention)

Answer 8

1. Lateral Prefrontal Cortex (PFC):
   - detection and processing of salient stimuli= ventral PFC
   - Goal-directed / working memory = dorsal PFC
2. Dorsal anterior cingulate
   - Responsible for error monitoring/response selection

Question 9

What are the roles of the Reticular Activating System in attention?

Answer 9

The RAS supports general alertness for attention and phasic alertness (quick response to stimuli)

Question 10

What can a lesion of the RAS lead to? What can extreme arousal lead to?

Answer 10

A lesion can lead to coma (0 arousal), extreme arousal can impair the flexibility of attention.

Question 11

What is the role of the Superior Colliculus in visual attention?

Answer 11

The Superior Colliculus controls the ability to visually fixate on or follow a moving stimulus through saccadic eye movements.

Question 12

Which specific nuclei of the thalamus are involved in arousal and selective attention?

Answer 12

1. Medial dorsal, reticular, and intralaminar nuclei of the thalamus are involved in arousal and vigilance,
2. The pulvinar nucleus is responsible for sensory gating (selective attention)

Question 13

What is the thalamus’s function in attention?

Answer 13

Acts as relay station for sensory and motor signals

Question 14

What functions are associated with the parietal lobe in attentional processing?

Answer 14

The parietal lobe is essential for attentional
processing: implicated in both selection and
resource allocation.

Question 15

What are the key attention-related functions of the parietal lobe?

Answer 15

The parietal lobe binds ‘what’ and ‘where’ information for stimuli, involved in visuospatial aspects of attention and overall attentional allocation, awarness of perceptual information

Question 16

What is the function of the Superior Parietal Lobule (SPL) in attention?

Answer 16

The SPL is crucial for shifting spatial attention, allowing us to redirect our focus to different spatial locations.

Question 17

What can damage to the IPL/TPJ cause in terms of attention?

Answer 17

Damage to the IPL or TPJ (temporateial junction) can result in spatial neglect, where a person ignores stimuli on one side of their body or space.

Question 18

What is the function of the frontal lobe in attention?

Answer 18

High level, executive
control of attention,
including dividing
attention between
two tasks

Question 19

What are the four different names for neglect in attentional disorders?

Answer 19

Heminiglect, Hemispatial neglect, Hemi-inattention, and Behavioural Inattention.

Question 20

How is neglect in attentional disorders characterized?

Answer 20

Characterized by a failure to respond or attend to stimuli on the side opposite of a brain lesion, which cannot be explained by visual, sensory, or motor deficits.

Question 21

What is a common test used to assess neglect? What will neglect patients often do during this test?

Answer 21

The line bisection test, where a person is asked to mark the midpoint of a line. Neglect patients will often mark the midpoint significantly off-center towards the side of space they do not neglect.

Question 22

What test can show the difference in perception between a patient with neglect versus one with hemianopia?

Answer 22

A patient with hemianopia would detect an object when turning their head to the left, placing it in their right visual field, whereas a patient with neglect would continue to ignore the left side of space.

Question 23

What are the two types of neglect demonstrated by writing and drawing tasks?

Answer 23

Body-centered neglect is demonstrated in a writing sample where the person starts writing from the middle of the line, ignoring the left space. Object-centered neglect is seen in a clock-drawing task where the person only draws numbers on one side.

Question 24

What are body centered and object centered neglect subtypes of?

Answer 24

Classic unilateral neglect

Question 25

What are the two types of neglect demonstrated by the symbol test?

Answer 25

Spatial neglect: Ignoring symbols on one side of the page, often the left.
Object-centered neglect: Only attending to part of each symbol, like the right half.

Question 26

What are the two competing theories about the cause of neglect?

Answer 26

1. Attentional Theory (3 hypotheses): Neglect results from from damage to the attentional
   orienting system
2. Representational: Neglect is the failure to construct a complete
   mental representation of contralesional space (refers to the side of the body or space opposite to the side of the brain that is injured or affected).

Question 27

What are the three attentional hypotheses to explain neglect?

Answer 27

1. Inattention or unawareness
2. Ipsilesional (right) attention bias: Attention is biased towards the damaged side of the brain, causing neglect of the opposite side.
3. Inability to disengage from right-sided
   stimuli

Question 28

What is the attentional hypothesis of unawareness/inattention in neglect?

Answer 28

Proposes that neglect is a failure to act in the left hemispace due to unawareness or inattention to the left

Question 29

What evidence supports the attentional hypothesis of unawareness/inattention in neglect?

Answer 29

In neglect, attention can be directed to the left by:
-Increasing motivation or adding emotional information.
- Making the stimulus array more structured.
- Using caloric stimulation (flushing ear out)

Question 30

What does the second attentional hypothesis suggest about the direction of attention bias in neglect patients?

Answer 30

Suggests that attention is biased towards towards the side ipsilesional (same side) to the damage in neglect patients.Ex: Attention is biased towards the right side which is ipsilesional to the damage (which is the same side as the brain damage) in cases of left neglect.

Question 31

Where is brain damage usually located in patients with neglect?

Answer 31

Brain damage in patients with neglect is typically located in the inferior parietal or superior temporal lobe of the right hemisphere, particularly affecting the temporoparietal junction.

Question 32

What is Heilman & Mesulam Ipsilesional Attention Bias Hypothesis?

Answer 32

Suggests that damage to the right hemisphere reduces arousal and attention towards the left side, , causing a bias towards the right side.

Question 33

How do the hemispheres direct attention differently in cases of damage, according to the attention-bias hypothesis?

Answer 33

The right hemisphere (RH) can direct attention to both left and right spaces, but the left hemisphere (LH) mainly directs attention to the contralateral space. Damage to the LH usually results in less severe neglect than damage to the RH.

Question 34

What does Posner’s “Inability to Disengage Hypothesis” suggest about attention in cases of neglect?

Answer 34

Posner’s hypothesis suggests that neglect might be due to their inability to disengage attention from the side they are focused on (usually the right side), making it hard to notice stimuli on the opposite side (usually the left side).

Question 35

What is the “Extinction” phenomenon, and how does it relate to Posner’s hypothesis about neglect?

Answer 35

Extinction in neglect recovery is when patients notice their neglected side but stop attending to it if the non-neglected side is also stimulated. This supports Posner’s hypothesis that shifting attention is difficult for neglect patients.

Question 36

What does the “Alternate Theory of Neglect” suggest about representational deficits?

Answer 36

The “Alternate Theory of Neglect” suggests that the issue isn’t just with reacting to external stimuli but also with internal representations. This means that patients with neglect may have a biased mental image of the world, ignoring one side even when imagining or recalling scenes.

Question 37

What are the components of the orienting subsystem according to Posner’s model?

Answer 37

The components are disengage, shift, and re-engage.