Executive Function

Question 1

What is the role of the executive function?

Answer 1

. supports voluntary goal directed behavior

. takes part in initiation, switching, inhibition, and planning

. components of decision making & problem solving

Question 2

What happens if you lesioned the prefrontal cortex?

Answer 2

. shows difficulty in initiating behaviors

Question 3

What happens if you lesioned/ damaged the dorsolateral prefrontal cortex?

Answer 3

. shows a disorder = abulia = reduced motivation, lack of initiation

. shows a disorder = akinetic mutism = lack of desire to move but are able to move & talk if desired
. a subject does not speak or move but tracks w/ eyes and can withdraw from painful stimuli

. memory is still intact

Question 4

What are the 3 different task switches?

Answer 4

. global switch cost
. local switch cost
. alternating switch cost

Question 5

What is the global switch cost?

Answer 5

. cost associated w/ performing mixed block of tasks compared to performing in sequence

Question 6

What is the local switch cost?

Answer 6

. cost associated w/ switching from one task to another

Question 7

What is the alternating switch cost?

Answer 7

. cost associated w/ switching back to task that you just switched away from

Question 8

How do you measure task switching in the lab and what are the results?

Answer 8

. using the N-back task with mix block (experimental) & pure block (control)

. Results = show additional activation of prefrontal parietal loops in mix block
. see increase in fatigue during task switching due to increased cognitive processing

Question 9

What functions rely on the prefrontal cortex?

Answer 9

. inhibit prepotent behaviors

. keeping distractors out of working memory

. remove unimportant information out of working memory

Question 10

How do you test for behavioral inhibition of prefrontal cortex in the lab?

Answer 10

. Stroop task

. subjects are ask to name the color in which it is presented

. shows the central executive is working to maintain the integrity of behavior

Question 11

What happens when you have damage in the lateral prefrontal region?

Answer 11

. see subjects having preseveration

Question 12

What is to preseverate?

Answer 12

. continue to perform an action when it is no longer correct even when they know that it is no longer correct

. results in the failure of flexible thinking

Question 13

What happens when you have large frontal lobe lesions?

Answer 13

. patients will spontaneously interact with stimuli when placed in reach (behavior is dictated by environment - field dependent behavior)

. see problem with inhibition of prepotent response

. see absence of personal goal oriented behavior

Question 14

What happens when you have lesion of the prefrontal cortex?

Answer 14

. will have poor planning

. inability to accomplish tasks efficiently

. will have inadequate time devoted to different task (poor planning)

Question 15

How would you test activity of the prefrontal cortex in lab and what are the results?

Answer 15

. utilizing the Tower of Hanoi task

. subjects are asked to move all disk to last tower without placing a larger disk onto a smaller disk throughout the multiple towers

. requires the use of working memory which patients with lesions of prefrontal have difficulty with

Question 16

What is the difference in the anatomy of the prefrontal cortex between humans and non human primates and other animals?

Answer 16

. humans and apes have prefrontal area larger relative to other regions of the brain

. demonstrates that prefrontal cortex have responsibilites of complex cognition

Question 17

What is the lateral prefrontal cortex composed of?

Answer 17

. dorsolateral & ventrolateral prefrontal cortex

Question 18

What does the medial prefrontal cortex include?

Answer 18

. anterior cingulate cortex

Question 19

What are the orbital regions of the prefrontal cortex responsible for?

Answer 19

. emotional processing

Question 20

What is the anterior prefrontal region (frontal pole) responsible for?

Answer 20

. engages in abstract problem solving task

. not visible in non human primates

Question 21

What are Broadmann areas 4, 6, 8?

Answer 21

. motor regions

. area 4 = ‘the worker’ (responsible for motor function - making voluntary movements)

. area 10 = ‘the ceo’ (responsible for planning of movement)

Question 22

What happens to the cells in the frontal cortex when moving more anterior of motor regions?

Answer 22

. cortex becomes more granular

Question 23

What kinds of cells exist in the prefrontal cortex?

Answer 23

. diverse pyramidal cells = more diverse inputs

. prefrontal cortex acts like sensory cortex in terms of circuits

Question 24

What are the different cerebral cortical layers?

Answer 24

1. molecular layer
2. external granular layer
3. external pyramidal layer
4. internal granular layer
5. internal pyramidal layer
6. multiform layer

Question 25

Which region of the brain provides inputs into the prefrontal cortex?

Answer 25

. thalamus (specifically the mediodorsal nucleus) . bidirectional input from higher cortical regions in parietal & temporal lobes

Question 26

Which region of the brain does the prefrontal cortex project to ?

Answer 26

. amygdala (mainly projects to ventromedial PFC) . hippocampus

Question 27

What are the functions of the dorsolateral prefrontal cortex? What happens when you lesion this area?

Answer 27

. embodies computational mechanisms for monitoring & manipulating working memory for active retention, selection, & updating representations . involves with executive function (motor planning, organization, regulation) . extremely prolonged maturation . requires connection from subcortical & cortical circuits for complex mental activity . lesion causes increased forgetfulness

Question 28

What are the functions of ventromedial prefrontal cortex?

Answer 28

. important for social decision making . plays role in inhibition of emotional responses

Question 29

What are the functions of anterior cingulate cortex?

Answer 29

. involves in rational cognitive functions (emotion, error recognition, problem solving) . plays role in autonomic functions (blood pressure, heart rate)

Question 30

What are the motor projection circuits to striatal regions?

Answer 30

. parallel cortical-basal ganglia-cortical circuits . circuits: cortex > striatum > GPi/SNr > thalamus . SMA > putamen > lateral GPi/SNr > ventral lateral nucleus

Question 31

What are the associative projection circuits to striatal regions?

Answer 31

. parallel cortical-basal ganglia-cortical circuits . circuits: cortex > striatum > GPi/SNr > thalamus . DLPFC/OFC > caudate dl/vm > medial GPi/SNr > medial dorsal ventral anterior nucleus

Question 32

What are the limbic projection circuits to striatal regions?

Answer 32

. parallel cortical-basal ganglia-cortical circuits . circuits: cortex > striatum > GPi/SNr > thalamus . anterior cingulate cortex > ventral striatum > ventral pallidum/SNr > medial dorsal nucleus