Lec 9 - Cognitive Control & Executive Functions

Case of WR

• Frontal Astrocytoma (tumor of astrocytes)

• Lose of goal-oriented behavior

  • Effected working memory

Cognitive Control

Allows info processing and behavior to adapt from moment to moment based on current goals

Frontal Cortex

Has bi-directional connection to most cortical and subcortical areas

Facilitation of Goals

• Relies on medial and lateral frontal cortices to cooperate

• Other factors: task difficulty + conflict detection

Medial PFC (ACC)

Detects conflicts, errors, and task demands

Lateral PFC (dlPFC)

Implements control adjustments, retains information

Supervisory Attention System (SAS)

• Network of interactive action schemes competing for activation

• Ensures behaviors are flexible

• Activation in anterior cingulate

Error-Related Negativity (ERN)

• Neg. deflection in EEF ~50-100 ms after error

• Stronger for incorrect responses

• Originates in ACC

• Reflects brain’s detection of errors BEFORE conscious awareness

Working Memory

• Where past knowledge or recent info can influence current behavior

• Mechanism needs to:

  • Reactivate stored info

  • Keep info active

WM Task

Must hold the location of award in mind

• Impairments if dorsolateral prefrontal lesions

Associative Memory Task

Build association between reward location + cue

• Dorsolateral prefrontal lesions cause no trouble

• Only if Hippocampal lesions = trouble

Malleable Representations

Same cells will respond to diff. stimuli when task changes

FFA activity

Most during stimulus presentation

PFC activity

Occurs most during delay in response

Prefrontal Cortex

Maintains currently relevant info, doesn’t store it

• Does this by interacting w/ more specialized cortical areas

Working Memory & Dorsolateral PFC (dlPFC)

• Lesion, Single Neuron, & fMRI evidence

Organization of dlPFC

• Spatial vs verbal

• Content vs processing load

Cognitive Control

• Maintain rules

• Switch between rules flexibly

• Identify and correct incorrect behavior

Frontal Lobe Patients during Wisconsin Card Sorting

• Perseverate (apply old rules)

  • Trouble in task-switching

Cognitive Control - Is Dynamic

Control —> Processing/Performance —> Monitoring —>

Studies of Response Conflict

• ACC activity leads to activity in dorsal-lateral prefrontal cortex

  • Exerts top-down control over performance

Mode of Cognitive Control

Prefrontal Lesions

Difficulty in goal-directed decisions

• + maintaining, retrieving, & selecting relevant rules & info is disordered

Dorsolateral Prefrontal Cortex

Involves in Working Memory

Region involves in task-switching

Ventral lateral prefrontal cortex

Anterior Cingulate Cortex

Detection & Correction of Errors