Neural Mechanisms of attention Flashcards
1
Q
Bottom -up Attention
A
- Stimulus driven control
- PaVlov= automatically orienting towards salient stimuli
- e-g.loud bang of balloon
- involuntary
- Reflexive attention
2
Q
Top- Down Attention
A
goal-driven control
- voluntary/ endogenous
- Ability to intentionally attend to something
- Bottom up + Top down attention systems are in balance
3
Q
overt visual attention
A
- physically directing eyes to stimulus
4
Q
covert visual attention
A
- mental shift of attention without physical Movement
5
Q
Helmholtz + Covert Attention
A
- screen of letters hung in dark room + light flashes on screen
- keep eyes fixed centre
- During brief illumination could perceive letters located within focus of attention better than those out even when eyes remained fixed on the centre
- shows we can concentrate attention without eegecvements
6
Q
Neglect Syndrome
A
- Indivs with lesions affecting right hemisphere fail to attend to the left side of the world controlesional)
- Pelligrino - copy clock drawing but squeeze all numbers on the right side
-Line cancellation test- asked to bisect lines in middle results show they bisect to right + completely miss lines on the left - Damage to right parietal cortex
7
Q
Description of neglect
A
- stimuli on one side of world is ignored
- Action less frequently directed to 1 side
- unilateral spatial neglect results when brains attention network is damaged in 1 hemisphere
- right hemisphere lesion biases attention towards he right, neglecting the left
8
Q
Bailints syndrome
A
- difficulty perceiving visual field as a whole
- deficit in eye movement to scan visual field
- Bilateral occipital parietal lesions
9
Q
Extinction
A
- Damage to right parietal cortex doesn’t always cause neglect
- Failure to attend to contralesional hemifield when stimuli appear in ipsilateral hemifield ( side of lesion)
- ## can attend to left t right sides vision but when themes competition they struggle to attend to the left
10
Q
Extinction evidence - Posner et al
A
- cueing task : Cues validly or invalidly indicating location of target
- Results = fail to reorient attention from invalidly cued locations in good hemisphere to target in bad hemisphere
- Attentional spotlight (cue ) affects reaction times by influencing sensory + perceptual processing
11
Q
large-scale network of attention
A
- neglect is result of damage to brains large scale attention network rather than a single structure
- Network includes Cortical + subcortical regions that are mono synaptically connected
12
Q
FMRI scans
A
- show which areas of the brain are most active
- strengths = good spatial resolution , non-invasive
- weaknesses = correlational not causal , expensive, doesn’t directly measure neuronal activity
13
Q
Evidence from neuroimaging
A
- ppts complete Posner’s cueing task
- Results show increased BOLD activity in brain regions during covert shifts of attention
14
Q
Limited capacity + bottlenecks in attention
A
- Brain has limited perceptual capacity
- Bottleneck sensory processing that filters TaSK relevant + irrelevant info
- Cockail party effect - cherry ( hear name from across party room)
- selective auditory attention allows you to ppt in a ConVO in a busy room while ignoring other sounds around you
15
Q
Early models of attention
A
- Bottleneck filters irrelevant info before complete perceptual analysis ( Broadbent)
16
Q
late models of attention
A
- Bottleneck filters irrelevant info after semantic info has been extracted
- Process all inputs equally + selection occurs at higher stages of processing determining whether the stimuli gains awareness or not
17
Q
Dichotic Listening studies
A
- 2 convos, 1 in each ear
- Attend to only 1 convo
- Asked if any recollection of the other convo
- provides evidence for + against both early + late models