attention, executive control and prefrontal cortex (L3) - Matt roser Flashcards
What is attention?
The preferential treatment / selection of a subset of information from more available sensory stimuli and thoughts
Attention involves both voluntary/controlled processes and involuntary/reflexive processes.
What is Broadbent’s model of selective attending?
A theory that involves top-down selection of relevant inputs at an early stage of processing, though some unattended information can intrude
Example: hearing your name in a crowded room.
What are the two types of selection in attention theories?
- Early selection
- Late selection
Early selection affects perceptual analysis while late selection affects higher-level stages like decisions and memory encoding.
What does the Posner’s cueing paradigm investigate?
Evidence for early selective attenuation of information from visual cueing of spatial locations
It measures reaction times (RTs) between valid and invalid trials.
What is the relationship between Valid and Invalid trials in Posner’s cueing paradigm?
RTs are fastest to targets in the Valid condition, suggesting preferential processing of stimuli presented at the valid target location
This indicates early selective attention.
What are the characteristics of voluntary and reflexive orienting?
- Voluntary orienting: slow, evoked by central symbolic cues, validity effects show up with long SOAs
- Reflexive orienting: fast, evoked by peripheral non-symbolic cues, validity effects show up with short SOAs
What is the difference between guided visual search and serial attention?
Guided visual search restricts the search to a subset of items based on a single feature, while serial attention requires searching to bind properties of objects together
Example: searching for a red circle among distractors.
What does ‘object-based attention’ refer to?
Attention can be influenced by objects, leading to faster reaction times when the target is part of the same object as the cue
Study by Egly, Driver, & Rafal (1994) showed this effect.
What is hemispatial neglect?
A disorder usually resulting from right parietal damage, leading to neglect of contralesional space, typically the left side
It reflects an attentional deficit rather than a memory deficit.
What are the three main attentional networks in the brain?
- Alerting: maintaining sensitivity to stimuli
- Orienting: attending to the source of a sensory signal
- Executive: directing attention according to goals
True or False: Attention is confined to one specific region of the brain.
False
Attention influences processing across multiple brain areas and is considered a modulatory process.
Fill in the blank: Attention selects information for preferential processing in a variety of ways, including _______.
[* Spatial location
* Item attributes
* Objects]
What evidence supports early selective attenuation in attention?
Early visual evoked potentials in extrastriate cortex show larger amplitudes for targets at valid locations than invalid ones
Study by Mangun & Hillyard (1991) provided ERP evidence.
What is the effect of attention on neuron activity?
Neuron’s preferred stimuli may become more specific with increased attention, indicated by a narrowing of the ‘tuning curve’
This was suggested by recordings in monkeys.
What are the implications of attention being modulated by top-down and bottom-up processes?
Selection happens at both early and late stages, and attention can be directed to various aspects like locations, features, or objects.
What are the purpose of executive functions?
Give organization and order to our actions and behavior
They govern cognitive, linguistic, and motor domains.
List the components included in executive functions.
- Representing and maintaining goals
- Planning for the future
- Inhibiting or delaying responding
- Initiating behavior
- Shifting between activities flexibly
What is the role of the prefrontal cortex (PFC)?
Involved in executive functions and working memory
It has several subregions including dorsolateral, ventrolateral, anterior pole, and ventromedial.
What are the three characteristics of PFC neuroanatomy?
- Late phylogenesis (evolutionary history)
- Late ontogenesis (developmental history)
- Highly interconnected with virtually all other brain areas (bilaterally)
What is the consequence of dorsolateral PFC damage?
Frontal executive syndrome
This syndrome includes problems in planning, adapting to new situations, and social withdrawal.
What issues arise from ventromedial PFC damage?
Problems with emotional control
Who was Phineas Gage?
A historic patient with ventral PFC damage
His case is often cited in studies of personality and behavior changes due to brain injury.
How do dorsolateral PFC lesions affect working memory?
Disrupt working memory and lead to stimulus-driven behavior
delayed alternation task in humans and monkeys
What is the Wisconsin Card Sorting task used to assess?
Cognitive flexibility and working memory
Patients with lateral PFC damage often perseverate with old sorting rules.
Define goal-oriented behavior.
Involves creating a hierarchy of goals and subgoals
Patients with frontal brain damage may fixate on certain aspects and fail to consider others.
What is task switching in the context of executive functions?
Intra- and extra-dimensional shifts between tasks
What does increased activity in the anterior cingulate (AC) gyrus indicate?
Increased task difficulty and monitoring of environment and behavior
What is the Error-Related Negativity (ERN)?
A negative component generated in the anterior cingulate following error decisions
It may aid in learning from mistakes.
True or False: Phineas Gage had problems with impulsive decisions.
True
What is Damasio’s somatic marker hypothesis?
Bodily sensations act as a heuristic guide to making decisions
-Ventromedial cortex is involved in emotions and emotions involve bodily sensations
What are the effects of vmPFC damage?
- Reduced inhibition of affect
- Deficits in reversal learning
- Impulsivity and myopia for the future
- Impaired reward expectation/prediction
What is the posterior to anterior gradient of control?
Selection of processing alternatives based on sensory information and contextual levels
This includes the context of prior episodes or events.
How are the frontal lobes organized for executive function?
Involves both posterior and anterior regions with varying levels of abstraction
Posterior regions handle concrete dimensions while anterior regions handle more abstract representations.
What functions are reviewed in the study of executive control?
- Response inhibition
- Set-shifting
- Working memory
What is the importance of the functions involving the prefrontal cortex?
Allow for thinking, planning, reasoning, problem solving, and goal-directed behavior
desribe the selective attending model?
what does the modified theory of attention diagram look like?
what shows up with validity effects in voluntary shifts of attention?
long stimulus onset ansynchronies (SOAs)
the delay between the presentation of the cue and the presentation of the target
what shows up with validity effect in reflexive shifts of attention?
short stimulus onset asynchronies
what is meant by visual search?
finding target features amongst distractors
targets defined by single features can be indentified preattentively - ‘pop’ out, targets defined by feature conjunctions require serial attention to bind the properties of objects togehter
what is a limit to guided visual search?
results in lesser impact of added distractors
search is restricted to a subset of items, based on a single feature
what did Wojciulik et al 1998 find in relation to attention to objects?
subjects can selectively attend to stimulis class and show correlated changes in inferotemporal regional brain processing
-> attentional deficits can track objects
what does neglect follow?
an object
deficit in attention to visual memories
what is meant by attention in the brain?
attention selects information for preferential processing in variety of ways:
-spatial location
-item attributes
-objects
how does spatial location effect attention?
increased activation is observed in sensory areas that are organized with regard to space, such as early visual-processing areas, and regions that provide a spatial map of the world, such as parietal regions.
how do item attributes effect attention?
activation is increased in the brain region specialized for processing attended characteristic, such as motion-sensitive area MT.
how do objects affect attention?
increased activation is observed in areas that process objects, such as the ventral visual-processing stream
what occurs in an intradimensional shift?
discriminate between two new black shapes
what occurs in the extradimensional shift?
discriminate between the two white shapes
how is working memory related to goal oriented behaviour?
allows information to be selected maintained, and manipulated to support coherent goal-directed behaviour
how can errors be avoided in attention?
AC activation is greater when people do tasks that elicit errors, such as the hard condition of the Stroop task, or with incompatible flankers
Inhibiting habitual responses
how do ventromedial patients perform on decision making tasks?
lack skin-conductance response to emotive stimuli
Fail to learn aversion to a risky decision – Iowa Gambling task
how are the frontal lobes organised for executive function?
contextual level (Koechlin & Summerfield, 2007)
abstraction level (Badre, 2008)
