Task 2

Question 1

Who proposed that the PFC is essential for working memory and when?

Answer 1

Goldman-Rakic proposed in 1987 that the prefrontal cortex (PFC) is essential for working memory, referring to the short-term maintenance of task-relevant information​

Question 2

What task do macaque monkeys with dorsal prefrontal lesions fail?

Answer 2

They fail spatial delayed response tasks, which require maintaining spatial information in memory for a few seconds

Question 3

What activity is observed in cells of the PFC during delay periods?

Answer 3

Many cells in the PFC show sustained firing during delay periods, with different cells coding for different spatial locations​

Question 4

What has research using fMRI shown about sustained activity in the human PFC during spatial memory tasks?

Answer 4

Activity is observed in the posterior PFC (area 8) during delay periods,

similar to monkeys,

but there is less significant activity in more anterior prefrontal areas​

Question 5

Why is it difficult to find sustained activity in area 46 of the human brain during working memory tasks?

Answer 5

The poor sensitivity of fMRI in humans

and the fact that only a small percentage of cells in area 46 show greater delay-related activity when remembering spatial cues compared to a control condition

Question 6

How did Goldman-Rakic interpret sustained activity in the PFC?

Answer 6

She interpreted it as reflecting the maintenance of sensory items in memory, crucial for performance on delayed response tasks​

Question 7

What factors, besides maintenance of sensory information, can sustained activity reflect?

Answer 7

Sustained activity can reflect response preparation and transformation of sensory input to the response

Question 8

When does sustained activity occur in area 46 during spatial working memory tasks?

Answer 8

Sustained activity in area 46 occurs only when subjects can prepare their response​

Question 9

What happens during the transformation phase in an oculomotor delayed response task?

Answer 9

Activity in the principal sulcus converts:

from cells representing the cue location

to cells representing the response location during the delay period

Question 10

How does the lateral PFC relate to task rules during the delay period?

Answer 10

Many cells in the lateral PFC fire differentially according to the specific rule in operation during the delay period

Question 11

How do reward expectations affect sustained activity in the PFC of monkeys?

Answer 11

Sustained activity during the delay reflects the monkeys’ expectation of rewards, with cells coding for both spatial location and expected reward in the lateral PFC​

Question 12

How does the expectation of high reward influence working memory tasks in humans?

Answer 12

High reward expectation combined with a difficult working memory task leads to interaction between delay-related activity and the expected reward size in the frontal polar cortex

Question 13

What is the role of the PFC in cognitive control?

Answer 13

The PFC extracts goal-relevant features from experiences and imparts rules to guide thought and action, essential for intelligent behavior​

Question 14

What are task contingencies, and how do they relate to the PFC?

Answer 14

Task contingencies are the logical structures of a task,

prefrontal neurons show tuning for learned associations between cues, actions, and rewards, helping to form ensembles representing these contingencies​

Question 15

What are the behavioral effects of prefrontal cortex damage in humans?

Answer 15

show impaired ability to organize their lives, becoming impulsive and irresponsible

Question 16

How do people with prefrontal damage perform on the Wisconsin Card Sorting Task?

Answer 16

They can learn the initial sorting rule but struggle to adapt when the rule changes, demonstrating difficulty in switching rules

Question 17

What does Miller’s model suggest about PFC connections?

Answer 17

The PFC connects to hidden processing units and strengthens associations leading to reward through reward signals, establishing task-relevant neural pathways dynamically​

Question 18

How do reward signals influence PFC activity?

Answer 18

Reward signals from the ventral tegmental area (VTA) influence PFC activity, affecting plasticity and sustaining activity to form associations between events separated in time​

Question 19

What sets working memory apart as a cognitive function?

Answer 19

Working memory retains information over potentially distracting events, unlike other cortical areas whose activity can be easily disrupted by distractors

Question 20

How does the PFC exert top-down control over other brain systems?

Answer 20

The PFC provides excitatory signals that bias processing in other brain systems towards task-relevant information, similar to selective visual attention

Question 21

What did studies on monkeys reveal about task-dependent activity in the lateral PFC?

Answer 21

Over half of lateral PFC neurons showed task-dependent activity, coding not just stimuli or actions but their behavioral context​

Question 22

How does the role of the PFC change with task practice?

Answer 22

The PFC plays a key role in task acquisition, but with repeated practice, task-relevant neural pathways are established in other brain systems, making tasks more automatic and less reliant on the PFC

Question 23

What is the role of the IFJ in attention?

Answer 23

IFJ biases perception in posterior regions through neural synchrony,

Using both top-down goal-directed and bottom-up stimulus-driven attention control​

Question 24

How do VLPFC and DLPFC differ in their roles in rule maintenance?

Answer 24

VLPFC is more involved in the retrieval and maintenance of complex rules,

DLPFC shows less engagement in rule maintenance during delay periods

Question 25

How does left VLPFC contribute to rule representation and maintenance?

Answer 25

It associates visual cues with appropriate actions, and is sensitive to rule complexity

Question 26

What role does the frontal polar cortex (FPC) play in rule representation?

Answer 26

The FPC helps elaborate on retrieved rules to guide behavior more effectively, operating on products of the lateral PFC

Question 27

What regions are involved in maintaining response contingencies during complex rules?

Answer 27

posterior VLPFC,

pre-SMA,

parietal cortices

Are engaged during the maintenance of response contingencies for complex rules

Question 28

How does experience-dependent plasticity manifest in the PFC?

Answer 28

Neurons in the PFC acquire sensitivity to task-relevant attributes with training, reflecting experience-dependent neural plasticity

Question 29

Why are predictions important for goal-directed behavior?

Answer 29

They are essential for forming associations and guiding behavior

Question 30

How does the PFC manage task switching and rule sensitivity?

Answer 30

Task switching activates a network of regions including the medial frontal cortex and ACC, while rule-sensitive regions in the PFC remain engaged regardless of task switching demands​