Executive Skills
Part 1: Definition, over-view, brain basis
Isabelle Rapin
Seminar in Developmental Disabilities
March 21, 2013
No conflict of interest
NIH Tool Box Definition*
Neurology March 12, 2013: S54-64
 Executive function (cognitive control) = topdown cognitive modulation of goal directed
activity
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Set shifting
Lateral prefrontal, anterior cingular, inferior parietal network
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Attention and inhibitory control (visual)
Frontal eye fields, posterior parietal, anterior
cingulate, thalamus, basal ganglia network
Working memory
Prefrontal, posterior parietal network
* Tests for uniform research projects
Definition
 Top-down executive/control system(s) -enable(s) endogeneously-generated goaldirected behaviors
 Some on-line requirements:
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•
•
•
•
•
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Planning (awareness of the future)
Motivation
Cognitive/behavioral flexibility (shifting)
Selective/focused attention
Inhibition of automatic sensory/affective responses
Sustaining active working memory
Exploit long-term memories (learning)
1. Schema of STM systems
Short Term Memory
Sensory buffers
Working memory
Sensory cortices
Prefrontal cortex
LTM declarative systems
Long term memory
Declarative
(explicit,items))
Episodic
(individual)
Semantic
(knowledge)
Non-declarative
(implicit skills, etc)
Several subtypes
More requirements
 Awareness of problem to be solved
 Advance planning
 Self-awareness, -monitoring
 Meta-cognition/multi-tasking
 Self-control, delay gratification
 Attend to feedback, shift accordingly
Executive function:
slowly maturing
 Requires repeated experiences to develop
 Modular aspects
• Visuo-motor
• Sensori-motor
• Verbal
• Implicit/social
 Considered “mature” @ start of 3rd decade
 Actually continues to develop life-long
 Susceptible to decay: dementia, frontal damage
Brodmann map in color
Brodmann (1909)
52 histologically
distinct cortical
areas
Prefrontal cortex
Gross anatomo-functional
approximations (most
functions are not localized)
Dorso-lateral prefrontal
~ area 48 working memory
Orbito-frontal
~ areas 10, 11, 47 inhibitory
Mesial prefrontal
~ areas 8-11, 13, 32 limbic
Scott, Schoenberg
Developmental disorders with
prominently affected executive
skills
 ADHD (attention deficit hyperactivity
disorders)
 ASD (autism spectrum disorders)
 Conduct disorders
 Etc.
Attention - Definition
 Presupposes vigilance (RAS)
 Ability to make choices among a myriad of
competing stimuli in order to match task
demands by
• Enhancement of attended stimuli
• Suppression of unattended stimuli
 Requires executive skills (prioritize, etc.)

“
working memory
Overlaps with attention
Control of attention
 Exogenous (reflexive, bottom-up – does
not require conscious awareness)
 Endogenous (cortical, top-down choices to
match on-going needs)
• Monitor & maintain goal directed activities
• Deactivate inappropriate tasks
• Prepare activation of relevant tasks
• Modulation by on-going affective signals
Major anatomic circuitry
 Subcortical areas (multiple neurotransmitters)
• Midbrain (ascending RAS, raphé, etc.)
• Intralaminar nuclei of thalamus
• Diencephalon, caudate
 Cortical areas (right dominant > left)
• Inferior parietal – multimodal sensory processing
• Lateral prefrontal - working memory, executive
• Anterior cingulate - interface cognition & emotion
ADHD
 ↓ sustained attention → distractible
 ↓ working memory → forgetful
 ↓ response inhibition → impulsive
 ↓ input inhibition and response monitoring
 ↓ awareness of affective signals &
environmental rewards
Autism
 Rigidity, narrow focus, perseveration
 Impaired awareness of social/
environmental cues
 But
• Selective/focused attention may be OK
• Inhibition of irrelevant sensory inputs may be
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OK
Memory (working and long-term) may be OK
Overlaps with memory
Multiple Memory Systems
 Short term memory systems
• Sensory buffers (for each modality +
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endogenous inputs from memory)
Working memory
 Long term memory systems
• Declarative (or explicit)
• Non-declarative (or implicit)
 Retrieval systems
1. Schema of STM systems
Short Term Memory
Sensory buffers
Working memory
Sensory cortices
Prefrontal cortex
Working Memory Circuitry
 Prefrontal cortex: in continuous on-line
reciprocal connections with
• Sensory cortices for each modality (specific buffers)
• Limbic circuits
• Arousal circuits
• Motor output circuits
***
 Note: Hippocampus circuitry: (data from amnestic
patients)
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Not critical on-line,
Critical for long term storage
LTM declarative systems
Long term memory
Declarative
(explicit,items))
Episodic
(individual)
Semantic
(knowledge)
Non-declarative
(implicit skills, etc)
Several subtypes
Declarative (explicit) LTM
1. Episodic
(Tulving)
 Uniquely human
 Powerful tool
 Specific particular facts/events
(autobiographical)
 Late to develop evolutionarily (man only?)
and ontogenitically (infant amnesia)
 Fragile to degeneration
 Critically dependent on (not limited to!)
hippocampal/medial temporal cortices
Declarative LTM Memory
2. Semantic Memory
 Knowledge (as opposed to remembrance
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of specific facts)
“Picked-up” knowledge
Starts at birth, long before episodic
memory
Broad and powerful
Much more resilient than episodic memory
Hippocampus system
 Binds inputs from all sensory modalities
with limbic and prefrontal executive inputs
 Reciprocally connected with relevant
cortical and subcortical circuitry
 Required for declarative LT memory
• For fresh and midterm declarative memories
• Not for very long term
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“
 Not required for non-declarative memories
Executive Skills
Part 2
Puja Patel
Seminar in Developmental Disabilities
March 20, 2013
No conflict of interest