Executive Functions- Olma Flashcards
definition of executive functions…
executive functions encompass higher order mental processes that involve a complex network which includes multiple cortical areas
the frontal cortex…
a. is the largest part of the cortex taking up 2/3 of the human cortex
b. is important for executive functions, and executive function ability correlates with the size of the cortex- the bigger size = more executive functions
c. is important for executive functions, and executive function ability inversely correlates with the size of the cortex- the smaller size = more executive functions
d. was developed in parallel to social development
e. is brodmann area 8
b
what are the subdivisions of the frontal cortex?
A. primary motor area
B. premotor area
C. prefrontal cortex
subdivisions of the prefrontal cortex (+ Brodmann areas)
- lateral PFC/ dorsolateral PFC (BA 9, 46)
- ventrolateral PFC (BA 44, 45, 47)
- ventro medial PFC (BA 10, 11, 25)
- orbitofrontal cortex (BA 10, 11, 47)
- anterior cingulate cortex (24, 32, 33)
- frontal eye field (8)
describe the connectivity of the PFC
- connected directly or indirectly to almost every part of the brain
- DLPFC connected to more sensory and motor (non emotional) areas
- VMPFC connected to more emotional areas (e.g. amygdala)
what are the dorsal and ventral attention system?
- dorsal attention system: top down visuospatial mode; decision goes from the bigger picture/higher order down to specific, planned attended details
- ventral attention system- bottom up visuospatial mode; stimulus is so salient that it draws one’s attention –> reorientation of attention
what NT systems project to the FC?
- dopaminergic system - fibres from VTA to FC
- noradrenergic system- coeruleo-cortical NE system
- serotonergoc system- fibres from raphe nuclei to some forebrain structures
- cholinergic system- fibres from basal frontal brain to the cortex
- GABA, Glu, Asp- prefrontal and prefrontothalamic axons
what is the role of the noradrenergic system in executive functions?
NE provides alertness–> low alertness affects executive functions
what is the difference in NT systems/projection between the DL-PFC and OM-PFC?
- NT systems of both: 5HT, NE, DA, Histamine..)
- DL-PFC- basal-forebrain cholinergic cell groups and monoaminergic groups project to DLPFC but not the other way around (DL-PFC cannot amplify NT release)
- OM-PFC- similar to the DL-PFC but the OM-PFC can amplify the activity of NT producing cells in order to enhance the activity in the OMPFC
what experiment was done to determine the PFC ability to adapt to changes in context conditions?
- Dopaminergic neurons in the PFC fire in response to an unexpected reward.
1. conditioning with natural stimulus
2. after conditioning–> natural stimulus alone will elicit a response of dopaminergic neurons
3. by reward ‘withdrawal’ –> activity of dopaminergic neurons is inhibited
what were the finding from the associative task and object oriented task experiment on monkeys?
associative task:
- task conditioned w. natural stimulus
- 3 stages: fix, cue, delay
- activity of dopaminergic neurons was very high at the cue stage (drawing attention) coupled with the reward
object oriented task:
- no coupling between reward and cue
- no difference between firing rates at cue stage as the attention was not drawn to the cue. in contrast, the neurons are firing to link between activity and behaviour.
Finding: same neurons have different functions depending on the task.
according to the attention control theory…
a. there are 2 modes of action control- CS and SAS. SAS is active normally, and the a new situation occurs it switches to CS to make behaviour flexible
b. there are 2 modes of action control- CS and SAS. CS is active normally, and the a new situation occurs it switches to SAS to make behaviour flexible
c. SAS is located in the OFC
d. executive functions require CS
b
what are the limitations of the attention control theory?
- how are sensory input and memory integrated?
- SAS is thought to be located in the PFC. SAS is strongly biased towards novel situation, so predicting normal routine actions should stay intact after disruption of the PFC. however, studies shoe that routine behaviour is impaired after damage to the PFC.
- not subregion specific–> not testable
according to the guided activation theory…(which of the following answers is/are correct?)
a. the PFC stores representations of task specific rules (templates). Goal related tasks increase activation of the posterior cortex, which is important for learning new rules
b. templates for executive functions are stored in the anterior PFC and are activated in response to different task
c. the role of the posterior cortex is to modulate template activation in the PFC
d. the role of the PFC is modulatory and should act in conjunction with the posterior cortex–>activation should increase with increasing control demand
e. It is unclear how new representations are transported to posterior regions that stores well learned behaviours
a, d,e
what are the problems with the term dysexecutive syndrome (DES)?
- variable constellation of symptoms
- high inter-individual variability
- very complex (–>difficult to measure)
