week 6 - executive functions Flashcards
what are executive functions?
‘conductor of the brain orchestra’
top most part of top down processing
they coordinate other brain modules to enable felxible, purposeful, goal-directed behaviour
why are executive functions needed?
needed to optimise performance in situations that require coordination between several cognitive processes
are executive functions specific to one domain?
no
supervisory, controlling or meta-cognitive (thinking about thoughts) rather than one specific domain (memory, perception, language, motor)
what are executive functions linked to?
linked to distinction between automatic (bottom up) and controlled behaviour (the latter requires execuitve functions)
strongly linked to the prefrontal cortex (PFC)
anatomy of prefrontal cortex
connection
PFC connected to almost all of the rest of the brain
anatomy of prefrontal cortex
three surfaces:
lateral
medial (middle)
orbital (very front)
anatomy of prefrontal cortex
lateral surface
implicated in ‘cold’ controlled processes (cognitive aspects)
anatomy of prefrontal cortex
medial + orbital
implicated in ‘hot’ control (emotional/social regulation of behaviour)
executive functions in practice
1986: identified five general situations requiring executive functions
situations:
1. involving planning or decision making
2. involving erro correction or trouble shooting
3. where responses are not well-learned or contain novel sequences of actions
4. judged to be dangerous or technically difficult
5. that require the overcoming of a strong habitual response or resisting temptation
executive functions in practice
experiment
the towers of london
executive functions:
planning and decision making
brain areas
tower of london task
PFC, especially dorsolateral, activated in functional imaging during task (healthy participants) and damage to PFC results in poor performance
executive functions:
error correction, trouble shooting and task switching
wisconsin card sorting test
requires shofts in strategy following an unexpected rule change
executive functions:
error correction, trouble shooting and task switching
brain areas
Ventrolateral PFC related to rule change
patients with PFC damage fail to update the rule and exhibit perservation behaviour
–> keep responding using a previously correct response
therefore PFC is involved in error correction and trouble shooting
DLPFC responded during the feedback period regardless of whether it was +ve or -ve
VLPFC more strongly activated for negative feedback, suggesting the involvement of this region when there is a need to change the rule
executive functions:
overcoming habitual response
test
stroop test:
functional imaging and lesion studies suggest involvement of anterior cingulate cortext (ACC) and pre-SMA (supplementary Motor area)
2007
executive functions
role of anterior cingulate (ACC)
detection of errors and detection of response conflict (potential errors)
executive functions
role of anterior cingulate (ACC)
evidence
monkeys with lesions here dont trouble shoot after making an error
the error potential at scalp may originate here
fMRI shows activity greatest on error trial, but lateral PFC greatest on error+1 trial
suggests ACC detects but doesnt correct erors
what are the two models of executive functioning?
non-unitary
unitary