Please enable JavaScript.
Coggle requires JavaScript to display documents.
Types & Models of Attention (Posner’s cuing paradigm (Valid &…
Types & Models of Attention
Types
Covert: attention not associated with eye movements
affected by peripheral vision
filtering tasks: observe a number of stimuli but attend to only one
Voluntary/ Top-down/ Goal-directed
endogenous
under the control of the person who is attending
Overt: attention to information being looked at (with eye movements, person moves his head toward the object)
measure with eye tracker (fixations, saccadic eye movements)
Reflexive/ Bottom-up/ Stimulus-driven
exogenous
driven by the properties of the objects themselves eg. sudden noise, motion
Selective: attending to one or a few sensory inputs while ignoring the other ones
d2 attention test, Dichotic listening task
bottleneck analogy: restricted flow of information eg. Broadbent’s Filter Model
limit to how much information can be processed at a given time
Posner’s cuing paradigm
assesses individual’s ability to perform an attentional shift
used in studies to assess the effect of focal damage or disorders on attentional ability and to understand spatial attention in healthy people
Method
observers are seated in front of a computer screen situated at eye level
instructed to fixate at a central point on the screen, marked by a dot or cross
To the left and the right of the point are two boxes
For a brief period, a cue is presented on the screen
Following a brief interval after the cue is removed, a target stimulus, usually a shape, appears in either the left or right box.
The observer must respond to the target immediately after detecting it
usually a computer keyboard which is pressed upon detection of a target
Following a set inter-trial interval, lasting usually between 2500 and 5000 ms, the entire paradigm is repeated for a set number of trials predetermined by the experimenter.
Cues
An endogenous cue : presented in the center of the screen, an arrow or other directional cue pointing to the left or right box on the screen, relies on input from the central visual field.
An exogenous cue: presented outside of the center of focus, can be an object in the periphery, but still within the visual angle, relies on visual input from the peripheral visual field.
Valid & Invalid Trials
valid trials: stimulus presented in the area as indicated by the cue
invalid trials: stimulus presented on the side opposite to that indicated by the cue
ratio of 80% valid trials and 20% invalid trials
A neutral cue could be a double-sided arrow --> neutral trial
electrooculography (EOG) to measure & differentiate between covert & overt attention
Posner encourages covert shifts in response to cueing
decreased reaction times for validly cued targets and slower reaction times in response to invalidly cued targets
Other Findings
Attentional shift to a target area occurs prior to any eye movement
Spatial attention is not completely reliant on conscious visual input
Cued attention is affected by age: older observers show longer engagement and delayed disengagement from cues compared to younger observers
Posner’s Model: 3 networks, each representing a different set of attentional processes
Alerting
Achieving & maintaining an alert state
Frontal & parietal regions of the right hemisphere
role of the brainstem reticular system in maintaining alertness
use a warning signal prior to a target event to produce a phasic change in alertness
norepinephrine as neuromodulator
Orienting
Selection of information from sensory input
frontal & parietal areas
Orienting manipulation: presenting a cue indicating where in space a person should attend, thereby providing a basis for the person to direct attention to the cued location
acetylcholine as neuromodulator (superior parietal lobe involved)
temporoparietal junction (TPJ) and the ventral frontal cortex (lateralized to the right)
Executive
Resolving conflict among responses
studied by tasks that involve conflict eg. Stroop
widespread connections from the midline cortex and the ACC
activity greater for targets than for nontargets, for conflict more than for nonconflict trials, and for errors more than for correct trials --> role of ACC in conflict monitoring
cingulo-opercular network: maintenance across trials, acts as stable background maintenance for task performance as a whole
frontoparietal network: mostly start-cue signals, relates to task switching and initiation and to adjustments within trials in real time
Individual Differences in network efficiency
Testing the efficiency and independence of attentional networks: The Attention Network Test (ANT)
30-min testing session that can be easily performed by children, patients, and monkeys
combination of cued RT & flanker task
Efficiency of the three attentional networks is assessed by measuring how response times are influenced by alerting cues, spatial cues, and flankers
The alerting effect calculated by subtracting the mean RT of the double-cue conditions from the mean RT of the no-cue conditions
The orienting effect calculated by subtracting the mean RT of the spatial cue conditions from the mean RT of the center cue.
The conflict (executive control) effect calculated by subtracting the mean RT of all congruent flanking conditions, summed across cue types, from the mean RT of incongruent flanking conditions
significant test- retest reliability
ANOVA 4x3 (cue condition x flanker type)
significant main effects of cue condition and of flanker type
significant interaction between cue condition and flanker type → Under all cueing conditions, the presence of incongruent flankers increased RT, however, this effect was enhanced when subjects were given alerting cues (center or double cues) that contained no spatial information.
significant difference between incongruent flankers versus the combined conditions of congruent and neutral flankers
incongruent flanking interfered with the processing of the target
The alerting network the least reliable with a test-retest correlation of (.52) & the executive control network the most reliable (.77)
Model of Corbetta & Shulman: two networks involved in controlling attention
Top down control
perceptual and motor sets as processes that link relevant sensory information to relevant motor information → 'attentional set'
for spatial attention: Areas in the occipital lobe respond transiently to the cue, whereas areas in the dorsal posterior parietal cortex along the intraparietal sulcus (IPs) and in the frontal cortex (FEF) show a more sustained response--> bilateral activation
dorsal frontoparietal network
for spatial attention, feature or object attention, working memory, attending to effectors, task sets,cognitive selection of stimuli and actions
left posterior parietal cortex recruited during the establishment or switching of task sets or stimulus–response associations
function to link relevant sensory representations to relevant motor maps, and dynamically to control these links
Stimulus-driven control
Strange things, moving things, wild animals, bright things, pretty things, metallic things, blows, blood, etc.
salience of objects influenced by their behavioural relevance
orienting to sensory stimuli modulated by both bottom-up and top-down signals → dynamic interaction
temporoparietal junction (TPJ) cortex & the ventral frontal cortex (VFC)--> lateralized to the right --> implications for Neglect
direct attention to behaviourally relevant sensory stimuli that are outside the focus of processing
frontal cortex might be necessary for evaluating the novelty of stimuli, whereas the TPJ might be more involved in detecting their behavioural valence
activation of TPJ–VFC during reorienting to spatially unexpected targets
The two networks interact
ventral network as an alerting system that detects behaviourally relevant stimuli in the environment, but is not equipped with spatial sensors. Once a relevant stimulus is detected, its precise localization depends on the dorsal IPs–FEF system
TPJ–VFC system as a circuit breaker of ongoing cognitive activity when a behaviourally relevant stimulus is detected
Hemineglect showing attentional problems (damage to the networks)
damage to the ventral network that also 'functionally inactivates' the dorsal network