Executive Functions

What is the lateral PFC?

working memory, goal-directed behavior, cognitive flexibility (adjusting behavior based on changing rules)

What regions are in the lateral PFC?

SM, PM, FEF, PC, V2, A2

What is the function of supplementary motor cortex (SM)?

Planning, initiation, and coordination of voluntary movements

What is the function of premotor cortex (PM)?

orchestrates complex, goal-directed, and voluntary movements using sensory-motor integration

What is the function of frontal eye lids (FEF)?

initiating voluntary, rapid eye movements (saccades), controlling visual attention, and managing visual perception

works for memory-guided movements and direct gaze toward visual targets

What is the function of parietal cortex (PC)?

spatial awareness, navigation, hand-eye coordination, and processing body position by integrating sensory information (touch, temp, pain, pressure)

What is the function of secondary visual cortex (v2)?

Intermediate processing stage taking in complex visual information like spatial frequency, orientation, color, & motion

What is the function of secondary auditory cortex (A2)?

In temporal lobe that processes higher-order complex auditory information, including sound identification, auditory memory, melody, and rhythm

its for interpreting speech, music, and environmental sounds

What regions are in the ventromedial prefrontal cortex / orbitofrontal cortex?

amygdala, MTL, s1/s2 (primary & secondary somatosensory cortices)

What’s the role of MTL?

• forming and retrieving long-term declarative (episodic and semantic) memories, spatial navigation, and emotional processing

• bridges short-term, working memory with permanent storage, facilitating relational learning and future imagining

• Includes the HC, amygdala, and adjacent cortex

What’s the role of s1/s2 (primary & secondary somatosensory cortices)

S1: detecting & locating sensory inputs

S2: integrating inputs with memory, emotional context, & higher order cognitive processing such as object recognition

What are shared regions of connectivity for white matter connections?

Thalamus, basil ganglia, anterior cingulate cortex, insular cortex

What’s the role of the thalamus

primary relay station for sensory and motor signals traveling to the cerebral cortex

• regulates consciousness, sleep-wake cycles, alertness, emotional processing

• filters, modifies, and integrates neural signals

What’s the role of basil ganglia

• motor control

• action selection

• habit learning

• reward-based behavior

gatekeeper: initiates voluntary movement by disinhibiting the thalamus while simultaneously suppressing competing movements via direct and indirect pathways

What’s the role of anterior cingulate cortex (ACC)

regulating cognitive, emotional, and motor functions, acting as an intersection between emotion and cognition

• monitoring performance, detecting errors, managing conflict, controlling impulses, and determining value of potential actions

What’s the role of insula

integrating bodily sensations, emotions, and cognitive processes

• internal sensations (interoception) and external stimuli

• regulates homeostasis

• self awareness

Which are the main frontal regions and white-matter connections?

Lateral PFC

• SM

• PM

• FEF

• PC

• V2

• A2

Ventromedial PFC/orbitofrontal cortex

• amygdala

• MTL

• s1/s2

Shared regions of connectivity

• thalamus

• basil ganglia

• ACC

• insular cortex

consequences of PFC damage

1. latpfc damage → dysexecutive syndrome

2. ventral PFC damage → disinhibition syndrome

what are two syndromes caused by PFC damage? what regions of the PFC are impacted?

latPFC → dysexecutive syndrome

ventral PFC → disinhibition syndrome

what’s dysexecutive syndrome?

• fail to plan for future

• rarely initiate new projects

• leave tasks uncompleted

• limited attention span

• difficulty interacting with others and understanding goals & thoughts

• deny having problems

what’s disinhibition syndrome

• constant movement not channeled toward productive activities

• euphoric / manic

• abnormal sense of humor

• fail to respond to social cues

• reveal embarrassing personal info

how does disinhibition syndrome compare to dysexecutive syndrome?

disinhibition syndrome

• cognition unimpaired, including response selection & WM tasks impaired in dysexecutive syndrome

• latpfc damage for dysexecutive tends to cause apathy and quietness

who is a famous patient who had disinhibition syndrome? what was his behavior?

• phineas gage

• had businesses but was just odd in social environments

what are executive functions

• processes that allow for flexible & goal-directed control of thought and behavior

what are behaviors governed by?

rules

what are control processes

• establish & modify rules

• engages rules in appropriate contexts

Taxonomy of executive functions

1. initiating new rules to match stimulus to actions based on goals

2. inhibiting inappropriate rules for the goals

3. shifting among rules to find rule more context appropriate

4. relating rules to generate more abstract rules

5. monitoring current environment

What is the switch operator metaphor of executive functions?

The PFC acts like a railroad switch operator to moderate socially appropriate behavior. This control is distributed across the cortex and is not localized to a specialized location

ex: when you're in a situation where the automatic response is inappropriate (e.g., you miss a shot and want to say "F**k" in front of your mom), the PFC reroutes you to the socially appropriate response ("Noo!") instead. When the PFC is knocked out (right diagram), that override fails and the impulse runs straight to the wrong output.

what are examples of evidence on the role of PFC in initiating new rules?

• PFC patients are impaired in initiation of action

  • may hve little spontaneity of thought or action, withdrawal from society, loss of interest, and abulia (lethargy & quiet withdrawal)

• matching vs nonmatching rule

how are rules encoded in brain

PFC neuronal populations are activated or not depending on context

how do the roles of PFC and basal ganglia differ regarding rule initiation? Parietal ctx?

PFC: code abstract rules

basal ganglia: map to more specific responses, object NOT rule switches

parietal ctx: rule creation for action generation via LIP neurons which show the expected value of possible actions

what’s the motor loop?

motor, premotor, somatosensory cortex → putamen → lateral globus pallidus, internal segment → ventrolateral and ventral anterior nuclei

what’s the prefrontal loop

dorsal PFC → anterior caudate → globus pallidus, internal segment; substantia nigra pars reticulua → mediodorsal and ventral anterior nuclei

what’s the affective loop

amygdala hippocampus, orbitofrontal, anterior cingulate, temporal cortex → ventral striatum → ventral pallidum → mediodorsal nucleus

what tasks show inhibiting previously valid behavior

1. oddball task

2. go/no-go task

3. stop-signal task

what are the 4 forms of inhibitory contorl

1. stopping previously valid behavior

2. preventing irrelevant info from interfering with other processing

   1. restraining socially inappropriate behavior

what’s the oddball task

few trials require inhibiting standard response

• scale ERP → p300

  • fMRI → DLPFC & parietal cortexw

what’s the go/no-go task

most stimuli require go repsonse but few require no response

• no-go stimulu → activity in latPFC & parietal cortex

• ERP/fMRI responses to no-go trials are impaired in disorders with inhibitory deficits (e.g, schizophrenia)

stop-signal task

•  respond to all stimuli but prevent response if a stimulus is followed by stop signal

• patient cases

  • Impaired in patients with right post VLPFC damage and in impulse control disorders (e.g, ADHD)

  • Impaired in Parkinson's disease (basal ganglia deficit) independently of

    generalized motor dysfunction  motor inhibition requires basal ganglia.

how does filtering relate to inhibiting previously valid behavior?

LatPFC patients → increased early/sensory ERPs to irrelevant stimuli → greater distractibility

acquired sociopathy

severe disinhibition syndrome

• Argumentative, profane, aggressive, and/or disinhibited

  sexual impulses

• A strong focus on present desires, disregarding family/work responsibilities & future plans

acquired vs congenital sociopathy

BOTH

• blunted affect

• extreme emotional outbursts

• poor decisions in social situations

acquired

• know rules fro reasonable behavior; can distinguish good vs bad

• impulsivity makes them choose bad behavior

• can feel remorse for their actions; doesn’t change their behavior

what task is used to measure rule shifting?

WCST

• piles according to a rule that is learnt by feedback (trial & error)

• But the sorting rule changes several times during the task

• So, the participant must abandon the old rule, discover the rule, and start using it

what’s perseveration

sticking with the old rule despite negative feedback

lateral PFC dysfunction performance in WCST test

• perseveration

• more random WCST errors

• increased susceptibility to distraction

what brain region is involved in WCST?

OFC

• reward or punishment

• heavily interconnected with sensory regions, brainstem interoception,and ventral pathway → important for incorporating affective information into plans for behavior

• OFC damage impairs learning of stimulus-contingences

• stimuli-reward mapping changes suddenly: animals with OFC lesions

  are impaired

what’s the reversal learning task OFC role

OFC damage impairs learning of stimulus-contingences

What region is associated with abstract rules

Combining simple rules into more abstract/general rules

• Component of most classic “frontal lobe tests”

• Impaired by frontopolar cortex damage

• Activates frontopolar cortex (FPC)

What are tasks measuring abstract rules?

1. comparing relationships in different series of items

2. Tower of London/Hanoi: imagine steps w/substeps

What do hierarchical models of latPFC organization propose?

The lateral PFC is organized front-to-back by abstraction level: posterior regions handle simple stimulus-response rules, while anterior regions (frontopolar) manage abstract goals and subgoals across time.

Koechlin's time-based model organizes control by temporal depth: sensory → contextual → episodic → branching control, each recruiting progressively more anterior PFC.

Badre & D'Esposito's abstraction model maps four task levels (response → feature → dimension → context conflict) onto increasingly anterior PFC regions, arguing the hierarchy is about representational abstraction, not just time

Koechlin's time-based model

organizes control by temporal depth: sensory → contextual → episodic → branching control, each recruiting progressively more anterior PFC.

Badre & D'Esposito's abstraction model

maps four task levels (response → feature → dimension → context conflict) onto increasingly anterior PFC regions, arguing the hierarchy is about representational abstraction, not just time

ACC role in conflict monitoring task

Response conflict → when info leading to incorrect responses is available earlier than info leading to correct responses → e.g., Stroop task

• In the Stroop task, ACC activity is greater for incongruent than congruent trials

• Also, ACC activity in one trial → increased DLPFC activity in the next trial→ ACC signals need for increased cognitive control

What’s error-related negativity ERN for 2 types of mistaken action?

• response ERN: motor response was incorrect

• feedback ERN: response not successful

• ERN correlates with RTs in next trial → engagement of cognitive control

what regions are there for ERN?

• ACC

• PCC

how is dmPFC organized?

• posterior to anterior gradient

  • response control: 2 conflicting resp (posterior)

  • decision control (choosing) middl e

  • strategy control (old to new strat) anterior

How does dmPFC resembles posterior-to-anterior gradient in LatPFC

• Corresponding lateral and medial PFC regions are more strongly preferentially connected

• More post. regions → select appropriate motor resp.

• More ant. regions → support functions related to

• using and modifying higher-order, abstract goals