Frontal Lobes and Executive Function Flashcards
Why are executive functions difficult to study?
- they are not directly observable
What are some examples of executive dysfunction?
- Parkinson’s
- substance abuse
- schizophrenia
- aging
According to the supervisory attentional system, what tasks require deliberate attentional resources?
- involving planning or decision making
- involved in trouble shooting
- ill-learned or contain novel sequences of actions
- tasks that are dangerous or difficult
- tasks that require overcoming of a strong habitual response or resisting temptation
What are the assumptions of the Supervisory Attentional System?
- actions under deliberate control involve additional mechanism than automatic actions
- attention modulates selection process with activation or inhibition
- attention is primarily relevant to the initiation of actions (not execution)
- selection between competing action sequences takes place through the mechanism of contention scheduling
What is the association in the supervisory attentional system?
- association between the contention scheduling and the basal ganglia/striatum dopaminergic system
What is an example of an overload and then broken contention scheduling?
- Parkinsonism
According to Alan D. Baddeley, what is central executive?
- attentional controller responsible for focus attentional resources, divding and switching attention
- homunculus-a little man who sits in the head and in some mysterious way makes the important decisions
Who coined the name “executive function” and what does it mean?
- Muriel Deutsch Lezak
- the ability to formulate goals, plan their execution and carry them over effectively
According to Maria Jurado, what is executive function?
- allow us to shift our mind set quickly and adapt to diverse situations while at the same time inhibiting inappropriate behaviours
- enable us to create a plan, initiate its execution and persevere on the task at hand until its completion
- mediate the ability to organize our thoughts in a goal directed way and are essential for success in school/work
How can we approach the elusive construct of executive function?
- brain-behaviour relationships (performance on cognitive tasks, neuroimaging)
- complex stats (latent variable analysis, within-subject designs)
- typical and atypical everyday life behaviours (rating scales)
- clinical samples (between-group designs)
What are some observable complex executive behaviours?
- decision-making, problem solving, self-regulation
What are some environmental influences on complex executive function?
- physical activity
- bilingualism
- musical education
- SES/nutrition
- parent-child interaction
What are some EF components?
- planning
- problem solving
- behavioural self-regulation
- judgement
- working memory
- initiation of action
What are some problems with the “unity and diversity of executive function” approach?
- conflation of concepts
- additional problems when the definition of a construct is based solely on description of outcomes
What are the 5 most common terms associated with executive functions?
- planning
- working memory
- inhibition
- set shifting
- fluency
According to the handbook of intelligence, when does intelligence emerge and when does executive function emerge?
- intelligence emerges when there is complexity
- executive functioning emerges when there is novelty
What are the three functions leading to a complex executive task?
- shifting
- updating
- inhibition
What is the unidirectional frontal lobe cortico-subcortical connections?
- caudate and putamen (striatum)
What is the bidirectional frontal lobe cortico-subcortical connections?
- nucleus medial dorsal
- pars magnocellularis (OPFC)
- pars parvocellularis (DLPFC)
What are the direct paths of the frontal lobe cortico-subcortical connections?
- hypothalamus
- mesencephalon
What are the indirect paths of the frontal lobe cortico-subcortical connections?
- hippocampus (via cingulate and parahippocampal gyri)
- amygdala (via uncinate fasiculus)
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What are the direct paths of the frontal lobes cortio-cortical connections?
- temporal and parietal lobes
- visual, auditor and somatosensory modalities via association cortex
- projections from the olfactory bulb to posterior OFL cortex
What are the indirect paths of the frontal lobe cortico-cortical connections?
- projections from the piriform cortex via the mediodorsal nucleus of the thalamus
What are the other frontal lobe cortico-cortical connections aside from direct and indirect?
- limbic systems
What is the DMPFC responsible for?
- reality testing
- error monitoring
What is the DLPFC responsible for?
- top-down guidance of attention and thought
What is the rlPFC responsible for? Where does it project to?
- inhibition of inappropriate actions
- striatum and hypothalamus
What is the VMPFC responsible for? Where does it project to?
- regulating emotion
- amygdala
What are the functional divisions of the prefrontal cortex?
- orbitofrontal
- dorsolateral
- ventromedial
- frontolimbic
What brodmann’s areas are a part of the orbitofrontal PFC?
- 10, 11, 13
What is the orbitofrontal PFC responsible for?
- inhibitory control over behaviour
- suppress or defer immediate gratifications
What Brodmann’s areas are a part of the dorsolateral PFC?
- 46 and 9
What is the dorsolateral PFC responsible for?
- working memory
- planning
- problem solving
- monitoring behaviour
What Brodmann’s areas are a part of the ventromedial PFC?
- 12, 32, 12/47
What is the ventromedial PFC responsible for?
- gives meaning to emotions
- maintenance of goals
- motivation
- attentional control
What Brodmann’s areas are a part of the frontolimbic PFC?
- 24 and 25
- ACC
What is the frontolimbic PFC responsible for?
- interpretation of emotions
- integration emotion-behaviour
- emotional control
What does PFC rich intra and inter-connectivity allow?
- access to all kinds of information
- ability to synthesize information
- direct connections to secondary and tertiary areas
- connections mediated by thalamus (indirect)
- feedback loops
- allows extraction of commonalities between situations (goals and rules)
What are three important underlying tenets of PFC?
- high level of plasticity
- adaptability (cognitive flexibility) and robustness (avoidance of distractors)
- recruitment in novel, top-down processing
What do the underlying tenets of PFC allow it to have the capacity for?
- capacity to sustain activity in the face of interference (interaction between inhibition and updating WM)
- capacity to actively maintain information allows associative learning
What are Milner’s main observations?
- frontal eye field in initial saccade suppression and correction
- cell activation before eye movement
- activation of FL in atypical associations between stimuli and response
- role of FL in utilization of external cues in behavioural guidance
- role of FL in spatial and nonspatial learning tasks (memory)
- FL association to temporal organization of behaviour
What is PFC main function (top-down control)?
- bias competitive inputs in the benefit of the generation of patterns of goal-oriented behaviour under novel conditions
What are the important features of PFC top-down control?
- “active memory in the service of control”
- protects fragile representations from interference of external or internal distractions
- promotes task-relevant operations
- inhibits inappropriate actions
What is the stroop test/effect?
- you ignore what the word says and instead state its colour
- inhibit word, enhance colour
In the stroop test what do the different functional areas do?
- posterior DLPFC: bias to task-relevant processes
- posterior dorsal ACC: select the information that should guide responding
- mid-DLPFC: bias to task-relevant representations
- anterior dorsal ACC: evaluate the response
How are WM representations in the PFC organized?
- organized by process (updating, order, manipulating) rather than material type (verbal, object, spatial)
What type of working memory engaged more frontal lobe?
- updating and ordering engaged more FL
- dual tasking and manipulating of information engaged less FL
What can be seen by prefrontal cortex development?
- that bigger does not equal smarter
- neanderthals had larger frontal lobes because they were engaging with the environment a lot (but not as complex and connected)
What are the three essential processes of prefrontal cortex development?
- myelinization
- gray matter changes
- synaptogenesis
What has been found about prefrontal cortex development through postmortem studies?
- ages 2-7: neuronal density decrease in PFC layer III
- age 3.5: highest value of synaptic density
- dendritic length growth and expansion of denstritic trees also observed
What has been found about prefrontal cortex development through in vivo imaging studies?
- FL maturation: back to front direction
- left PFC matures earlier than right PFC
- FL gray matter increase during a short window: pre-adolescence (males peak at 12 and females at 11)
How does the prefrontal cortex develop?
- shared networks at early stages in development and subsequent fractionation
What is the role of inhibition in EF development?
- increased inhibition as a sign of enhanced voluntary attention
- language serves a maintenance function for self-regulation through social interaction
What are some important gains during EF development?
- from perseverative behaviour to cognitive flexibility
- from reactive to proactive control (AX-CPT)
What is perseverative behaviour?
- making an error in a task and getting feedback but continuing to make the same error
What is continuing performance task (CPT)?
- task : when you see an X then click but only if proceeded by A
- children will see A and click even if X is not after
What are the steps in the problem solving approach (an EF developmental model)?
- problem representation
- planning
- execution (intending/rule use)
- evaluation (error detection/correction)
What can we see from the “colour game”?
- 3 year olds able to play colour game but once switched to shape game cannot change tasks
