Week 11: Attention

Question 1

What is attention?

Answer 1

Prioritising and enhancing the processing of certain information

Question 2

What is arousal/alertness?

Answer 2

Global state of attention

Continuum from being asleep to being wide awake

Question 3

What is arousal regulated by?

Answer 3

The reticular activating system (RAS)

Question 4

What is vigilance/sustained attention

Answer 4

Vigilance - maintenance of attention for infrequent events over long periods of time - declines overtime and is affected by our general level of arousal

Easiest to measure in a lab

Question 5

Selective attention?

Answer 5

Attending to some stimuli while ignoring others

Question 6

Why is selective attention required?

Answer 6

We are constantly bombarded with information from our senses and we need to make decisions about what to attend to - inhibiting unwanted inputs and facilitating attending to relevant ones

Question 7

Divided attention?

Answer 7

Ability to allocate central attentional resources to perform more than one task at a time - switching between the tasks

Question 8

Selective attention can be….

Answer 8

1. Voluntary - we have a particular goal so we direct our attention towards this, endogenous (from within), top-down
2. Reflexive - stimulus driven, attentional capture, exogenous (from the outside), bottom-up

Question 9

What is overt attention?

Answer 9

Move our eyes, head and body towards a region of interest

Question 10

What is covert attention?

Answer 10

Can pay attention to spatial locations independently of our eye gaze

Eg. cocktail party effect

Question 11

What two concepts demonstrate selective attention?

Answer 11

1. The cocktail party effect

2. Dichotic listening

Question 12

Bottleneck theory of attention (early selection)?

Answer 12

Selective filter that switches between competing sensory inputs so that only one input then gains access to the limited capacity decision channel also known as STM - can then go on to receive higher level analysis

INPUT IS SELECTED PRIOR TO COMPLETION OF PERCEPTUAL ANALYSIS

Question 13

Limitations of bottleneck theory?

Answer 13

We know from the cocktail party effect that information does sneak through this filter

Question 14

Late selection models of attention?

Answer 14

Suggest that all sensory inputs receive some low level analysis - then reach a stage of semantic encoding

When someone says something that is interesting, even though it is unattended, it has been processed at a semantic level and has meaning so we can potentially switch to attending this information (cocktail party)

Question 15

Attenuation theory?

Answer 15

Hybrid model
All info receives some processing - allowing our attention to be directed if it contains important information
Items in unattended channels of information have different thresholds of recognition depending on their significance to the individual. Thus, a significant word (e.g., the person’s name) would have a low threshold and, when mentioned, would be recognised even if that person’s attention is concentrated elsewhere

Question 16

What do we know about attention capacity?

Answer 16

Its capacity is limited so we do need to make decisions regarding what to attend to in order to receive higher order processing

Question 17

Unilateral spatial neglect?

Answer 17

Neglect of one side of space following unilateral damage to cortical or subcortical areas (one hemisphere) - occurs despite normal vision

TYPICALLY DAMAGE TO RH PARIETAL

Might not eat one side of the food on their plates

Typically will improve on its own - seen through artist with this condition and the progression of his paintings during the improvement - can tell he starts to pay attention to the other side of space again

Question 18

Visual search task and neglect patients?

Answer 18

Eye tracking used

• Neglect patients show an eye movement bias towards one side when searching for a letter target - ignoring one side and attending to the other
• Normal controls search entire space

Question 19

Object vs. space based neglect?

Answer 19

Space based: Don’t attend to objects in the left hand side of space
Object based: attend to objects on the left hand side of space but only to the right half of the object

Suggests attention can be directed within space or within objects

Question 20

Can neglect occur with imagined images?

Answer 20

E.g. People who lived in Milan were asked to imagine famous buildings from that area and report those that they were imagining - neglect patients failed to report buildings on left but when asked to imagine from a different position, they reported the initial neglected ones and neglected the others

Question 21

How do we know that neglect is not from a visual or perceptual deficit?

Answer 21

The concept of extinction

• can recognise isolated stimuli in either visual field
• Problem occurs when they are presented in the same visual field at the same time

Failure to perceive or act on stimuli opposite to the lesion when simultaneously presented with stimuli on same side to lesion
- Simultaneous presentation leads to other stimuli side being extinguished

Question 22

So if neglect isn’t a loss of ability, what is it?

Answer 22

May be an attentional bias

• Sensory inputs compete for awareness

Question 23

What is Balint’s syndrome?

Answer 23

Bilateral damage to the parietal and occipital lobes

Attention is so tightly focussed on one object at a time that it is not possible to attend to other objects at same time even when they overlap in space

3 main clinical symptoms:

1. inability to perceive more than one object at a time (simultanagnosia)
2. Inability to reach in direction of an object under visual guidance (optic ataxia)
3. Inability to voluntarily shift gaze to new visual stimuli (ocular apraxia)

Question 24

What is a covert orientating task? (Posner cuing)

Answer 24

Can test voluntary spatial attention
- Fixate on a central cross
- An arrow cue indicates the likely direction in which the stimulus will appear
- Target stimulus appears
Arrow may correspond with this arrow (valid)
May oppose this arrow direction (invalid)
Or the arrow may point to both directions (neutral)

What we see if that compared to a neutral trial there is a reaction time advantage for valid trials
Reaction time cost for invalid trials - they need to disengage from the location they have been directed to and reorientate to the opposite location - takes time

Question 25

What brain structure shows activation during attention and is used as evidence for early selection?

Answer 25

Activation of the thalamus | visual attention in lateral geniculate nucleus

Question 26

Exogenous spatial cueing experiments for reflexive spatial attention?

Answer 26

Found that if there is a short gap between the cue and the stimulus appearing, reaction time was shorter than un-cued stimulus appearance However, once the gap between cue and stimulus increases, we see a shift in this with reaction time being greater than un-cued responses = INHIBITION OF RETURN

Question 27

What is inhibition of return?

Answer 27

Recently attended locations seemed to be marked as places that we don't need to return our attention to - might be an evolutionary mechanism (scanning environment - need to keep checking new locations)

Question 28

Visual search task dimensions?

Answer 28

If there is only one dimension that differs between the target item and the distractor items, it is a fairly easy task HOWEVER, if there is more than one dimension that differs, it is harder (conjunction of form (8 or S) and orientation) and need to search more

Question 29

Feature integration theory?

Answer 29

If searching for single feature then search times are independent - we don't need to search the whole array because that single feature just 'pops out' Extra striate areas that are responsible for things such as colour motion etc are all activating in parallel Conjunction search? Spotlight of attention deployed sequentially to integrate feature maps onto a master map of locations - automatic scanning process that moves around from item to item biased to locations that are more salient to the task (if looking for red, drawn to red areas)

Question 30

P1 activation if probes are placed at target-relevant locations during visual search tasks?

Answer 30

Greater P1 amplitude than when probes were at irrelevant locations - suggesting our attention is drawn to potential target locations. Creates a benefit for enhanced processing at this location

Question 31

Object specific area processing in brain regions?

Answer 31

When looking at eg. a house and face fused together in a photo, you see activation in the responsible brain regions swapping between which one you are focussing on

Question 32

Attentional network theory?

Answer 32

According to this theory, there are 3 functionally and structurally seperate networks in attention: 1. Alerting network - associated with general level of arousal and vigilance 2. Orienting - directing of attention to prioritise external information 3. Executive control - higher level regulation of information from other systems

Question 33

Alerting network?

Answer 33

Automatic/arousal based network that originates in the locus coeruleus which are norepinephrine projections from the cortex (part of RAS) - also linked to autonomic NS causing us to be hyper aroused if needed 2 types of alerting: - Tonic alerting: general level of vigilance (tasks where you need to respond any time there is a target) - Phasic alerting: Where we might be cued to the fact that something is about to happen (alerted that we might need to respond soon - cueing tasks can test)

Question 34

orienting network?

Answer 34

Allows us to prioritise information by selecting locations, features, etc Dorsal system (frontal eye fields & parietal areas): Can be automatic or voluntary (top-down eg looking for red things, prioritise red) Ventral system: right lateralised. Bottom-up reorienting. interrupting what we are currently attending to and reorientate to salient information - Mediated be acetyl choline Posner cuing tasks

Question 35

Executive control network?

Answer 35

Important for top-down control over other systems - helps to prioritise information important for current goals and also the voluntary control over current focus Fronto-parietal network: important for moment to moment aspects of completing a task - eg. resolving conflicts and switching between tasks Cingulo-opercular network: helps for task-set maintenance - helps to keep task in mind and to also regulate other systems to perform task Mediated by dopamine Stroop tasks (inhibit word representation), wisconsin card sorting (sort cards according to unknown rule - need to regulate behaviour)

Question 36

Role of frontal eye fields in orientating attention control networks?

Answer 36

Voluntary eye movements, gaze shifts and covert visuospatial attention This attention increases connectivity between FEF and visual areas Participate in the top down guidance of attention

Question 37

Which network is most commonly associated with neglect syndrome?

Answer 37

The ventral attention network + extinction Damage to the temporal parietal junction often leads to problems disengaging in stimuli so if attentional focus is on a particular stimulus, we actually need to disengage from this stimulus and damage affects this process

Question 38

What role does the superior colliculus play in attentional networks?

Answer 38

Detect and shift attention to the salient locations via reflexive eye movements Really is specific to eye movements to attended targets

Question 39

What is the pulvinar important for?

Answer 39

Pulvinar of thalamus is important for covert and overt attention Also a role in filtering distracting information (greater activation in cluttered displays - when filtering is required to just attend to a particular target)

Question 40

What happens if a GABA agonist is injected into the pulvinar?

Answer 40

Disrupts the shifting of covert attention to the opposite visual field regardless of whether the stimulus was valid or invalid Again suggests that the pulvinar is important for covertly engaging spatial attention