Executive Functions

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Executive Functions

• Planning / Decision-making / Goal abstraction
• Social Interactions / Inhibition
• Working memory and response selection
• Maintaining and manipulating information over
  short periods
• Inhibiting impulses and controlling emotions
• Other executive functions
• Encoding and retrieving long-term memories
• Learning and hypothesis testing
• Allocating attention
• Time travel (thinking about the past and future)

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Frontal Lobes

• Frontal lobes constitute approx. 35 of brain in
  all primates
• It is the amount of white matter that has
  increased in evolution hence the amount of
  connections
• Developmental changes
• Neuronal pruning infants born with certain
  number of neurons, decreases with development,
  BUT white matter increases (increased
  myelination)
• Pruning occurs primarily from 4-6 yrs and 11-14
  yrs.

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12-01
W. W. Norton
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Frontal Lobes Functional Subdivisions

• Lateral Prefrontal Cortex
• Working memory, problem solving
• Anterior Cingulate
• Conflict/error monitoring
• Ventromedial Prefrontal Cortex
• Emotion regulation, social inhibition

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A BAD DESIGN
ETHMOID RIDGE
SPHENOID RIDGE
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40 Cases of Head Trauma 1937
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Frontal Lobe Damage

• Behavioral changes
• flat affect, blunted emotional response and
  decrease in drive (abulia)
• lack of self-awareness regarding alterations in
  behavior, emotions, and thought processes
• Imitation and utilization behavior
• Cognitive Changes
• Inability to initiate, stop, and modify behavior
  in response to changing stimuli
• WISCONSIN CARD SORT (hallmark of frontal lobe
  tests)
• Inability to organize and plan cant move across
  time-spectrum
• Inability to inhibit responses
• STROOP task
• Perseveration Stuck on set, time, or action

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Frontal Lobe theories

• Dynamic Filter
• Boosts some signals, filters others
• Goal Abstraction
• Organizes behavior to accomplish abstract goals
• Organized by Processes
• Response selection, encoding, retrieval,
  maintenance, manipulation, reward processing
• Organized by Domain
• Language, what/where pathways

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Suppressing Unwanted Memories

• A neural basis of Freuds psychological model for
  voluntary suppression of memories
• Involves an interaction between control processes
  (prefrontal cortex) and memory retrieval
  processes (hippocampus)

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Method

• Subjects were trained until they memorized 73 of
  the 36 pairs
• In the scanner, subjects saw a cue from one of
  the pairs for 4 sec,
• Respond trials, subjects retrieved the response
  and kept it in mind
• Suppress trials, subjects kept the response out
  of mind
• After scanning, subjects were tested with the
  same cue or on an completion task to test their
  memory of the

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Results

• Suppress trials werent remembered as well as
  respond and baseline trials
• Suppress trials activated more lateral PFC and
  Respond trials activated more hippocampus

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Results
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Results
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Conclusion

• The results suggest a biological mechanism of
  memory control the ability to stop a memory
  from coming into consciousness
• This active suppression of unwanted memories
  causes forgetting of that information
• May be a good model of suppression of traumatic
  events