Psych 351B: Midterm 3 Review (Central Executive)

Simon Task

Participant is told to ignore the location of a shape and respond with a right press if the shape is a triangle and left press if the shape is a circle

What is an incompatible trial in the simon task

Triangle is on the left/circle is on the right

What is a compatible trial in the simon task

Triangle is on the right/circle is on the left

Simon effect

The difference incompatible and compatible trials with regard to response time 

How can we determine that the system involved in switching attention is the same as executive attention

Compare the arrow task and a modified version of the simon task where the task relevant dimension was the location of the shape

Monitor brain activation during these tasks and see if it fits with what we expect

What is found with regard to activation for the switch (arrow) task

Activates the inferior parietal lobe and extrastriatal visual cortex

What is found with regard to activation for the compatibility (simon) task

Activates the anterior PFC and premotor cortex

What can we conclude regarding the arrow and simon tasks

Switching tasks and attributes seems to involve similar neural mechanisms and that these mechanisms are located in the parietal cortex and frontal lobe

Go-no-Go Task

Participant is told to respond to every letter of the alphabet by pressing a button as quick as possible except for the letter X

What is found regarding no-go trials (when X is presented)

More activation in the orbitofrontal region, where greater activation leads to more accurate responses

Stop-signal Procedure

Participant is told to respond yes/no to question but sometimes unexpectedly told to stop (inhibit response)

T or F: The closer the stop signal is presented to the question, the easier it is to stop

T, because longer delay leads to lower ability to inhibit response (the physical motor response)

Inhibition in children

If a child is shown a sweet under a cup and the cup is moved in their FOV, they will continue to say the sweet is in the original cup location

Why does inhibition in children work in such an odd way

Theory is that infants cannot inhibit previously rewarded response due to lack of developed response inhibition

Conclude this because they attend to the right place but reach for the wrong one

Sequencing

Hint: executive system

The claim that maintaining the coding for order is part of the executive system, it is a metaprocess (horizontal faculty)

What is the problem with ordering with regard to the executive system

How is it that sequencing is a horizontal faculty in this system (PFC) but a vertical faculty in the phonological loop (parietal lobe). Resolved using an item vs order task

Item vs Order task

Item: Participant given sequence of letters and then a lowercase probe, respond with yes/no regarding probe being in list

Order: Participant given sequence of letters then a lowercase letter and respond with next letter after probe

What is found regarding frontal-lobe damage with regard to the item-order task

They are deficient in coding order information but sufficient on item information

What are the 3 ways a string of letters can be coded for order

1. Directed association

2. Order tags

3. Familiarity

Directed association

One makes pairs between successive items, hence farther apart items take longer to be deduced

Order tags

Tags are attached to items, so time is not scaled with distance for response

Familiarity

Participant checks how familiar a pairing feels, hence information is represented continuously.

The farther apart items are the less familiar they are and thus RT should be quicker

What evidence is used for familiarity based judgements

If one is shown a vertical sequence of letters, then a probe (two letters) and asked if the probe is either an item in the sequence or in order of the sequence

fMRI: showed activation in dorsolateral PFC and parietal cortex which are areas order and item relate to respectively

What evidence is used for sequence processing

One is asked to generate a novel script of how to accomplish a goal

Those with PFC damage cannot do this as they cannot break goal into subgoals

What evidence is used for monitoring processing

One is shown a sequence of 6 items and asked to point to a specific item, do this 6 times and told to not pick a previously picked item

Those with PFC damage will do worse than those with temporal damages they cannot remember what they chose in the past

T or F: Those with PFC damage would do as well as controls if the order did not change

T, note that they are not impaired on naming all six of the items