executive function Flashcards
executive function
the ability to plan actions to reach a goal, guide or control behaviour towards the goal, use information flexibly, think abstractly, and to references
must be exerted in new situations when no preexisting plan/template for how to act exists
required when typical responses must be overridden or inhibited
ie/ saying “you too” to enjoy your meal to serving (the act of stopping this)
also called cognitive control, a term indicating a process in which one is guiding or controlling one’s thought and action
more than one function usually contributes to the performance of executive abilities
it is therefore difficult to link each function to a specific brain region
executive deficits
most commonly observed after damage to the frontal lobe, including white matter connecting frontal regions to other brain areas
difficulties can arise despite normal functioning in other “intellectual processing” area
what skills does completing a task involve
staying on task - with a goal in mind of what we are trying to do
sequencing info
modifying strategies
using knowledge in your plans
monitoring actions - what is the best action to take ie/ using a knife in drawer to spread butter instead of the fork on the counter
goal-directed behaviours
guiding behaviour toward a goal is multifaceted
losing any facet of goal-oriented behaviour can derail the entire plan
completing a task involves a number of skills
these functions rely on patterns of activity within overlapping portions of the frontal lobs, as well as the degree to which it influences or interacts with other regions of the brain - taking info from other regions and deciding what to do with it
frontal lobe damage
causes people to wander off task
can’t stay with assigned task
creating and maintaining a goal task
process that designates which information is task relevant
stroop task- a cue appearing 1.5 seconds before the stimulus indicated whether the person should identify the colour named by the word or the font colour of the word
the lateral prefrontal cortex became active during the cue period, prior to presentation of the stimulus (in response to a cue that designates a specific task set
the greater the degree of activation in the left lateral prefrontal cortex after the cue, the less a competing colour name slower responses
lateral prefrontal cortex became active during the cue period, prior to the presentation of the stimulus (in response to a cue that designates a specific task said)
the greater the degree of activation in the left lateral cortex the cue, the less a competing colour names slowed responses
lateral prefrontal cortex is involved with creating and maintaining a task set
more activation = better at performing task
stroop task: task set for determining ink colour is difficult with the distracting would read words automatically = activation in the lateral prefrontal regions
task set for automatically = activation in the prefrontal regions
when it is harder to maintain a task set, there is greater activation in the lateral prefrontal cortex
what do prefrontal areas do
help us stay on task, especially when irrelevant information is particularly distracting
sequencing and planning
to reach a goal, one must determine what steps to take to attain the goal and in what order those steps must be taken
requires knowing what comes before and what comes after; tasks that have just been accomplished versus those tasks that are about to be performed
dorsolateral prefrontal regions may be important in sequencing items because they support executive processes that act on information being maintained in working memory
choosing a sequencing strategy
another important aspect of sequencing behaviour is the ability to choose which sequence or strategy best allows for a goal to attained
patients with frontal lobe damage are less likely to report that they use strategies
one task used to assess strategy is the Tower of London Task
task switching
the path to a goal is not always simple linear progression
- often there are unexpected twists and turns that require task-switching. ie/ coming into new problems
the classic neuropsychologist test used to examine task switching is the wisconsin task sorting test
Wisconsin card sorting test
neurologically intact people adjust their responses accordingly to new task
people with executive dysfunction perseverate - understand that it is not what they are supposed to be doing anymore, but they can’t pull themselves away
brain areas activated during performance of the wisconsin card sorting task
dorsolateral prefrontal cortex
ventrolateral prefrontal cortex
inferior parietal lobe
temporoparietal association cortex
basal ganglia
brain areas that activate during task-activation
likely to be directed by an executive control system that is independent of the systems that actually perform each of the individual tasks
patients with left frontal lobe damage have a specific deficit in task switching
increasing activity over the left DLPFC via transcranial direct stimulation can augment task-switching abilities
meta-analyses of brain imaging studies also implicate the inferior frontal junction in task switching
task switching and the brain
the location of inferior frontal junction that has ben shown to play a prominent role in switching between tasks
psychological inertia
caused by executive dysfunctions
hard to start an action, but once engaged, equally hard to stop
damage to medial frontal regions, including the supplementary motor area and anterior cingulate
evidence suggests that regions of the medial prefrontal cortex are involved in determining how much “effort” (what you are willing to put in) will be exerted to reach a goal
less connectivity
regions of the anterior cingulate involved in calculating the degree of effort required to obtain an outcome
