Visual Attention Flashcards
What is saccade?
- Rapid, voluntary shifts in eye positions between steady fixations
- we voluntarily move our eyes when we are looking at a scene or reading
Review circuitry for voluntary saccades
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What are the pathways for saccades?
Posterior parietal cortex (LIP) and frontal eye field send signals to superior colliculus which sends signals mesencephalic and pontine reticular formations. These control eye movement
WHat is bottom up attention?
Certain visual features e.g. distinctive color, movement, flashing light “catches our attention”
What is top-down attention?
Delibaretly directed by the brain. You’re told what to pay attention to
What are overt attention and covert attention?
Overt: changes in eye gaze direction
Covert: attention directed without gaze change
What are consequence of attention?
Visual acuity, reaction times
What are the two types of searches?
Pop-out search (target can be identified by one feature) and conjunction search (target defined by the conjunction of two or more features)
What is Feature Integration Theory?
Spatial attention: attention to particular spatial location “glues” features together.
Each feature can be analyzed without attention in parallel within multiple feature maps (in specialized cortical areas)
What is the effective stimulus?
V4 cell responds well to vertical and horizontal red bars in its RF
What is the ineffective stimulus.
Does not respond to vertical and horizontal green bars in its RF
What does FEF stimulation do?
It enhances (red) V4 cell response to a visual stimulus
Review Frontoparietal attention network (last slide)
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Describe the frontoparietal attention network for bottom-up attention
- input about conspicuous object is passed from visual areas in the occipital lobe to area LIP
- construction of salience map
- visual processing of a salient object is enhanced
- eyes may move to five are the object
Describe the frontoparietal attention network for top-down attention
- attention effects occur first in frontal and parietal areas. Behavioral goals established here
- priority map in LIP and FEF
- visual processing enhances perception of selected object
- eyes may move
