Essay plan Flashcards
Awake States-
Cherry
Inattentiveness & Attentiveness.
E- Cocktail part effect- Cherry 1952
Early selection theory-
(N1 amp)
(Broadbent)
Late selection theory-
(dichotic listening)
Early- process sensory inputs prior perceptual analysis.
E- Larger N1 amplitude when sound attended to v not.
E- Broadbent’s Model of Attention- gating mechanism determines what limited info passed on for higher analysis. - evidence early selection.
Late- act after complete perceptual processing of sensory inputs.
E- Dichotic listening task- told attend 1 ear, if relevant info in other- switch attention
Endogenous attention-
(posner-type task)
-evidence early selection
Exogenous attention-
(posner-type task)
Endo- sustained, top-down, voluntary
E- Posner-type task.
- RT to valid trials faster then invaild/neutral
E- Early selection- contralateral side of Visual Cortex larger on valid.
Exo- transient, bottom-up, automatic
E- Posner-type task
-RT faster <250ms- bottom-up facilitation, post that Inhibition Return Mechanism.
Spatial attention-
Feature based attention-
visual search paradigm
specific location in space.
specific stimulus feat.
E- Visual Search Paradigm- RT not alter due set size. Conjunction search- increase RT- scan all.
Feat based- diff cortical sites & activates before spatial is visible
Rep visual areas of brain
EEG & PET- evidence Early Selection model
Retinotopy- orderly rep retinal image in brain- used define cortical areas using fMRI.
Single cell responses (evidence for attentional modulation).
(attend to stim)
attention (top-down) to stimulus increases firing rate
attention improves neural coding (msg clearer).
Biased Competition Theory
Reynolds
Reynolds et al 1999- Monkeys. Pref stim= increased firing rate. Non-pref stim presented at same time as pref stim= supression of pref- competition.
If attend to pref- almost elim unattended stim.
Feature Selective Attention
areas to what stim- V5 etc
V5/MT- motion
V4- colour info & objects
Feature Selective Attention- Processing pathways -
Visual Cortex
Dorsal (posterior parietal)- movement & spatial info
Ventral (inferior temporal)- object & certain colour feats.
Object Based Attention
Egly
even if only attend to part object- auto spread along it.
Egly et al- cued location strongest activity, then uncued on that object, then uncued on diff object.
Fusiform Face Area- faces
Parahippocampal Place Area- houses
Attention Networks
(ECS)
(hopfinger)
Executive Control System- control aspects of external/internal world relevant & which behaviour to select.
Parts- Frontal Cortex, Parietal Cortex, Thalamus (pulvinar) & Superior Colliculus (midbrain).
E- Hopfinger et al 2000- Spatial cueing paradigm- causes activity in areas above.
2 attentional networks influence processing.
top-down, bottom-up
Top-down- Fronto-Parietal Network - for voluntary control–> Medial parts of Parietal & Frontal Cortex- active to direct attention.
Bottom-up- novelty & attentional reorienting/disengagement–> Lateral parts Parietal & Frontal Cortex- active to direct attention.
Older parts brain involved in attention
mid & pari
Midbrain-
neurons on Super Colliculus- visual stimuli in rep field increased firing if behaviorally relevant.
Parietal Cortex-
neurons in Parietal Cortex- visual stimuli in rep field increased firing if behaviorally relevant.
Premotor Theory
(FEF)
(electric stim V4)
attention to object/spatial location precedes & linked motor acts towards objects/location.
Frontal Eye Field- controls where look/attend (can be dissociated as Covert Attention)- sends info back to visual areas.
E- electrical stim of Neurons in V4- as if attention to that location- proof feedback connections.
Neglect-
Extinction-
Neglect- ignore side contralateral to lesion.
Extinction- diff perceiving objects in Hemifield contralateral to lesion.
Unilateral lesions to Parietal Cortex result- unilateral spatial neglect & extinction (usually stroke).
