W7 brain - attention and distraction Flashcards
(22 cards)
Orienting is
shifting attention to specific location, object or event
- localisation of objects is neurally coded
- spatial map in primary visual cortex (occipital)
- where we attend is neurally coded
- fovea visual field
- periphery less detail
Overt vs covert
Overt = moving eyes with focus of attention
Covert = attention moving eyes still
Top-down vs bottom-up attention
**top-down **= endogenous - active goal-directed; wheres wally, red top in crowd
bottom-up = exogenous - noise, calls my name
Posner cueing task
clap when you see the star
- endo top down - arrow guides where to look
- exo bottom up - border around box grabs attention to look
arrow or border cue captures attention, reaction times faster
ERPs in orienting
P1 is
P1 component = peak 100ms after stimulus
both types of attention elicit the P1
- cued bottom-up larger P1 than uncued
- top-down, told to look left larger P1
Different brain networks/areas for top-down, bottom-up are:
Dorsal attention network = top-down attention
- intraparietal sulcus, frontal eye fields
Ventral attention network = bottom-up
- TPJ, ventral frontal cortex
Attention bias is object-based
- attention selects information by objects
- stimuli attended to, objects, rather than shape/colour
STROOP test
selection is biased to global>local shapes
- big letter made of smaller letter
- longer reaction time for local (small)
- faster for global (big shape letter)
eg. an E made of ‘A’s
fMRI evidence object attention bias
houses vs faces stimuli
- more FFA fusiform face area activity for viewing faces
-more PPA when attending to house
THEREFORE, we can attend to both even when they overlap
- attention will go to where its told
attention neglect occurs when
there is damage to brain hemisphere (eg stroke)
- fail to attend to stimuli on opposite side of lesion
- eg lesion right, ignores left
eg drawing a clock
two types of neglect:
- space-based
- object-based
Space-based neglect is
- egocentric (your own left/right)
- eat on one side of plate
- read one side of page
object-based neglect
- allocentric
- fail to notice certain sides
- relative to object eg half a letter
- draw half a clock, only see ‘WER’ in FLOWER
LIMITED CAPACITY OF ATTENTION
Attentional blink task
- 2 letters amongst stream of numbers
- target 1, then target 2
- easier to recall T1
- 200ms after lag 2 (time between 2 targets)
- can find T1, there is an attentional blink, dont notice T2
- processing T1 delays attention to T2 (T2 masked,decay)
- if T2 appears straight after, then spared
Bottleneck model is
- attentional resources have limited capacity
- stage 1= attention stored of targets -
bottle= targets go through, non-targets stay in stage 1
-** stage 2**= memory consolidation,plan
T1 target flows to 2, non-targets stop T2 getting in
T1 then T2 both in
Capacity limits through ERP
Vogel 1998
- stimuli stream - T1 number, T2 red letter
- only looking for T1= no impairment
- T1, lag T2, attentional blink
- if T2 white flash probe, sensory info
- attentional blink at p300 (WM)
- blink not observed in N1 +P1, meaning stimuli is perceived, not impaired
info can come in, but hard to report what we saw precisely
fMRI pixelated stimuli
- T1 pixel face
- T2 scenes PPA
- more PPa when scene was missed than when no scene
- meaning of stimulus can be represented without conscious awareness
- less FFA when cant report, but still FFA if missed
Biased competition model is
- idea that attention is an emergent property to resolve neural competition
- look at one thing more brain activity than all at once
DISTRACTIONS
Attention capture task
- find the circle
- is it tilted left or right?
- red distractor square stops us from seeing what we need (circle)
results from attention capture task
- slower response about target when colour singleton (distractor) is present
- fail to see probe of salient distractor
- fail to look at distractor first
- this show suppression of distractors
Pd component- ignoring distractors on contralateral opposide to visual
Inhibition of return
Posner cueing task
- if cued to an area (square border around star), initial attention attends less 500msto 3 seconds after cue
- protective of distraction
- allocated attention, nothing there, longer to return back there
Emotional distractors
emotion-induced blinkness task
- house rotated to left
- people saw shark
- impaired after emotional image
- we prioritise emotional stimuli
N2 component = attentional selection
