Attention Flashcards
What is attention?
An umbrella term used to refer to processes someone uses to choose information for further processing
–Alertness and arousal
–Vigilance
–Selective attention
–Divided attention
Alertness and Arousal
Most basic levels of attention
Vigilance
Ability to maintain alertness over time
Selective attention
The selection of information essential to a task
When we selectively attend to a stimulus, mental effort is required
– focusing and concentrating
2 types:
– bottom up attentional selection
– top-down attentional selection
Dichotic Attention (listening/ reading/ etc.)
The response to stimulus is enhanced when is it present in the attended location compared to when it’s not
— the ear you are attending to/ giving some attentional focus experiences more activation when a tone is heard.
Divided attention
Split attention across tasks
Where does attention occur?
What are critical brain areas for attention?
No specific place for it in the brain
Attentional processing is performed by/ associated with a functional network of different subcortical and cortical brain area
—Critical brain areas for attention:
> Reticular activating system
> Superior Colliculus
> Thalamus (LGN and Pulvinar)
> Anterior cingulate cortex
> Parietal Cortex
> Frontal Cortex
Reticular Activating System functions
– overall arousal and sleep-wake cycles
– Damage can result in a coma
– Dorsal Sub-system
–Ventral Sub-system
RAS Dorsal Subsystem
Projects to the cortex cia the thalamus
> relies on Aceytlcholine
RAS Ventral Subsystem
– Projects to cortex via basal forebrain
> 2 Pathways, Serotonin (raphe nucleus) and Norepinephrine (locus coerelius)
Vigilance and Sustained attention systems
– Cholinergic and Noradrenergic systems
— More effort needed to sustain attention = more acetylcholine
— Noradrogenic prepares the brain to receive information
– Thalamus interfaces arousal and sustained attention
– Cortical regions (especially right hemisphere) involved
— Activation of right hemisphere seen in vigilance tasks
Bottom-up attentional selection
Some intrinsic aspect of the stimulus causes your attention to be brought to it
- Subcortical areas play a role in mediating stimulus-driven/ involuntary attention
Evolutionary perspective
– subcortical orienting mechanisms developed first, responsible for mediating more basic stimulus driven processing
Top-down attentional selection
Individual decides where to direct attention
- Cortical areas (parietal and frontal cortices) play a role in mediating goal-driven/voluntary attention
Evolutionary perspective
– Cortical orienting mechanisms evolved more recently and are responsible for higher-level goal-driven attention shifts.
Attentional Selection
- Subcortical areas play a role in mediating stimulus-driven/ involuntary attention
- Cortical areas (parietal and frontal cortices) play a role in mediating goal-driven/voluntary attention
Evolutionary perspective
– subcortical orienting mechanisms developed first, responsible for mediating more basic stimulus driven processing
– Cortical orienting mechanisms evolved more recently and are responsible for higher-level goal-driven attention shifts.
Dichotic Attention (Selective attention)
Attended vs. Unattended stimulus
Paying attention to one thing, but not the other, despite both being perceived (but not processed)
Selection Models
Early-Selection Viewpoint
Late-Selection Viewpoint
Early-Selection Viewpoint Model
Selection occurs earlier in processing, before items are identified
Attended speech»_space; Attentional Speech»_space; Semantic analysis»_space; Longer-term memory
Problems:
– even unattended perception is processed/ influences overall hearing
Late-selection Viewpoint Model
Selection occurs only after sensory processing is complete and items are already identified and categorized
Attended speech»_space; Sensory buffer»_space; Attentional Selection»_space; Longer-term memory
Problem:
Hard to process everything that comes at you
Intermediate Selection Model
Attended speech»_space; Sensory Buffer»_space; Semantic Analysis»_space; Longer-term memory
– If something we recognize is brought up, we can skip past all the levels
– Things you are paying attention are prioritized when attending to something, higher general threshold for unattended speech, lower threshold for important things
Superior Colliculus: Automatic Orienting
– Plays a role in the localization of visual stimuli, the control of saccades, and stimulus-driven attentional shifts to stimuli in visual space
– Superior colliculus is well-situated for attentional processing and linking eye movements
— set of neurons that quickly respond to visual stimuli
— retinotopic map of the contralateral side of space
— Has a different set of neurons sensitive to both sensory characteristics and to orienting movements
— The inferior colliculus plays a similar role for auditory info
EVIDENCE:
– Lesions to this area disrupt attention shifts
What two major parts of the Thalamus play a role in Selective Attention?
2 Major parts (nuclei): Pulvinar and LGN
LGN and Selective attention
Thalamus
– gatekeeper to the cortex
Can enhance and suppress information based on relevance
Pulvinar and Selective attention
Thalamus
- Aids in regulating information transmission between cortical regions processing relevant information
- helps synchronize activity between brain regions
- filtering: freater activation of the pulvinar when identifying small targets surrounded by distractors as opposed to large targets with no distractors
Selective attention and Parietal Lobe
Involved in the overall allocation of attentional resources to a particular stimulus or task.
Plays a role in selecting information in a more precise manner after the early gating of sensory information by the thalamus.
- Involved in types of attentional selection:
– Types of selection involve different regions of parietal lobe: the superior parietal lobe, the inferior parietal lobe, and the intraparietal sulcus.
Regions of the Parietal Lobe
Superior parietal lobe (SPL) is involved in “top-down” influences on attention directed by the person’s goals or desires rather than stimuli in the environment.
Inferior parietal lobe (IPL) of the right hemisphere are more involved in more bottom-up aspects of attention control.
Intraparietal sulcus (IPS) is where these two streams of information are thought to be integrated.
Superior Parietal Lobe
- Top-down influences on attention, directed by the individual
Inferior Parietal Lobe
Right hemisphere
Bottom-up aspects
Intraparietal sulcus
Other two parietal streams of information are thought to be integrated
Visual Search
- If something makes something stand out/ look different, visual search is faster
- The more objects, the harder this process gets
- Depends on features of the target
Feature Integration Theory
- Targets defined by only one feature will “pop out”
— preattentive/ parallel search - Targets defined by feature combinations requires attention to put features together
— attentive/ serial search
— gets hard the more objects/ visual noise there is
The theory:
Attention allows the feature of an item to be “glued” together - Basic visual features are detected automatically and processed in parallel across all locations in a display
— attention is required to bind these different features to form the percept of an item
Feature Integration Binding Process
- Damage to parietal regions disrupts the ability to bind features together
– Patients with such deficits cannot detect the conjunction of features, whereas their ability to detect a single feature remains intact
– TMS applied to the right parietal cortex of neurologically intact adults increases the time for conjunction searches but not simple feature searches
Salience Maps
- Some information prcessed automatically helps influence where attention is directed (bottom-up)
- Top-down information is also an influence
- Both these influences form a salience map, which helps decide where attention should be directed
— the IPS (intraparietal sulcus) is essential for salience maps (part of the parietal regions)
Feature Maps
- Different signals for the presence of each feature
- If a unique feature: target can be found only using the feature map, attention goes to that location on the master map
- If no unique feature: Attention must be directed in a serial search to locations in the master map
- Attention to a master map location provides access to information at that location in each of the feature maps
- This integrates the features possessed by the item at the location
Illusory Conjunctions
→ Attention is required to combine the features of objects
→ Attention is also required to precisely determine the locations of object features
→ When attention is limited, may not properly put features together in the right location
→ Features can get mixed up: illusory conjunction
Inattentional and Change Blindness
- When attention is focused on a location or an object, it is withdrawn from other locations or objects
- Unattended objects are processed less efficiently than the object that is attended to
Neural Bases of Divided Attention
- Divided Attention occurs when attention is split between different sources of information or between different tasks
- No consensus on what neural systems allow for multitasking
— Some suggest increased activity in prefrontal regions
— others argue that increased prefrontal activity is because of greater demands of the brain under divided tasks rather than divided attention itself
Automaticity
- Learning a skill requires careful attention
- with training, attentional demands decrease
- some skills/ tasks become automatic, requiring minimal attention to perform
- multitasking can be possible when attentional demands of different skills/ tasks decrease to the point where performing both at the same time does not exceed our capacity for attention
- Tasks that require cognitive processing cannot be automatic
Stroop Effect- Is reading automatic?
- Stroop effect shows that reading is automatic
- Individual words: yes, understanding sentences: no
- Regardless of practice, comprehension of phrases never becomes automatic
- This is why there are limits to multitasking. Things that require conscious processing aren’t automatic
Response-Related Selection
- Anterior Cingulate Cortex, more involved the harder a task gets
— Intracranial recordings show alterations in activity just prior and after a response
— neuroimaging findings suggest that these regions specifically increase their activity when response mappings are hard - ACC involved in response section
— activated during Stroop interference
Lateral Prefrontal Cortex and Goal Selection
- Lateral prefrontal regions serve as sources for top-down attentional control
- they send signals to posterior brain regions that act as the sites of attentional control that are actively involved in the selection process
– bias towards processing certain information that you choose
————-
Prefrontal regions are top-down sources of attentional control that modulate activity in posterior brain regions
Source + Sites of Attentional Control
Sources: Prepping Stuff
Sites: where it occurs?
Attention can act to select information in a variety of manners
Selective attention can be directed to a particular position in space, a particular item attribute, or a particular object
Effects of attention are observed in regions of cortex that are specialized to process the attribute on which information is being selected (space-based, object-based, attribute-based)
Alerting, Orienting, and Executive Attention Model
Attention can be divided into 3 systems:
1. Alerting
2. Orienting
3. Executive Attention
Alerting (Alerting, Orienting, and Executive Attention model)
Allows the brain to maintain a tonic level of arousal and to respond to signals warning of upcoming events
—> Involves the:
»> Locus Coeruleus
»> Thalamic regions
»> Frontal and Parietal regions
»> linked to norepinephrine
Orienting (Alerting, Orienting, and Executive Attention Model)
Aligns attention w/ sensory signals and selects among multiple sensory inputs
—> Involves the:
»> Superior colliculus
»> Parietal areas
»> Frontal eye fields
»> linked to acetylcholine
Executive Attention (Alerting, Orienting, and Executive Attention Model)
Controls how attention is directed to goals and desires
—> Involves the:
»> Basal Ganglia
»> Lateral Prefrontal Cortex
»> Anterior Cingulate
»> Linked to dopamine
Dorsal Attention System
System prepares and applies top-down (goal-directed) selection of stimuli and responses
»> composed of portions of the intraparietal cortex (Intraparietal sulcus = IPS), superior frontal cortex, and frontal eye fields
Ventral Attention System
Detects and reorients attention to behaviourally relevant stimuli, especially notable (salient) or unexpected
»> composed of the temporoparietal cortex (temporoparietal junction = TPJ), inferior frontal cortex, and anterior insula
»> Mainly lateralized to the right hemi
Dorsal and Ventral Attentional System interactions
> Exchange of inputs said to occur between the TPJ (Temporoparietal junction) and the IPS (Intraparietal Sulcus)
Ventral is sensitive to new stimuli, dorsal precisely locates these stimuli once attention is brought to it by the ventral
