Development of Executive EVR: Control in … canada/KimberlyEspy.pdfDevelopment of Executive Control in Preschoolers Kimberly Andrews Espy, Ph.D. •Could no longer hold down job;

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Development of Executive Development of Executive Control in PreschoolersControl in Preschoolers

Kimberly Andrews Espy,

Ph.D. ••Could no longer hold down job; invested and lost life savings inCould no longer hold down job; invested and lost life savings inrisky business with questionable former corisky business with questionable former co--workerworker•• Tardy, disorganized, fired from job repeatedly. Tardy, disorganized, fired from job repeatedly. ••Family left him, remarried, divorced again, considering 3Family left him, remarried, divorced again, considering 3rdrd..••Indecisive (taking 2 hours to shave, could not chose restaurant)Indecisive (taking 2 hours to shave, could not chose restaurant)••Preoccupied with details, saved useless objectsPreoccupied with details, saved useless objects

--Phineas GageEVR:EVR:••Married 15+ yrs, father of 2,Married 15+ yrs, father of 2,••Accountant, promoted thru ranksAccountant, promoted thru ranks•• @32 was the firm Comptroller@32 was the firm Comptroller••Family describes as Family describes as ““Natural LeaderNatural Leader””•• Active in church, well respected Active in church, well respected

@ 35, @ 35, orbitofrontal meningioma, compressing both frontal lobes

EVREVR……..

•IQ=125+• WMS = 140•Halstead-Reitan – WNL•MMPI - WNL

•Excellent knowledge of current events, public policy, economy, complex social issues, but

poor implementation in everyday context

=>=>““Knowledge/Action DissociationKnowledge/Action Dissociation””

Executive Control?Executive Control?

• Late to develop =>> protracted vulnerability

•Function of prefrontalsystem (cortex & related,interconnected structures

•Processes that subserve regulated, goal-directed cognition and behavior

EC in developmentEC in development……Prenatal Cocaine ExposurePrenatal Cocaine Exposure

• Cocaine is a sympathomimetic, imitates DA action in CNS by blocking DA transporter, leaving more DA in the synaptic cleft

• Chronic prenatal exposure leads to down regulation of receptor binding sites, chronic DA depletion

• Toddlers performed adequately on Bayley, but were inattentive, perseverative, and seemed to lack basic goal direction that clinical testing did not capture….How to measure these abilities?

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Measuring Executive AbilitiesMeasuring Executive Abilities……

Wisconsin Card Sorting Test

•Prototypic executive task….WCST

•If can’t do WCST=>then no executivecontrol

•Perhaps a measurementissue?

PreschoolersPreschoolers……Executive Control???Executive Control???• Inattentive, spontaneous, unmodulated… look for

common, emergent cognitive threads• Ontogeny => later organization• Large changes in development of prefrontal cortex

– Myelination– Synaptic connections & bio-electric organization

• Young children have less complex cognitive processes, so executive control may be more evident than adults if use developmentally appropriate tasks.

=>Where to turn??

Delayed Response ParadigmDelayed Response Paradigm

Ablation or physiological alterations = >

Working MemoryImpairments

Diamond had adapted for use in infants,…Why not for older preschoolers?

-Non-verbal response

-Minimal motor requirements

-Engaging, rewarding format

Delayed Search & Bayley Performance

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Errors IQ Eq

CE NE CE NE

p < .05

SS

Program Aim: How does Program Aim: How does executive control develop in executive control develop in

preschool children?preschool children?• What is the

developmental ontogeny of executive control?

• How is executive control organized?

• How is executive control altered by various types of neuropathology?

• What are the sources of individual variation in executive control?

• How is executive control related to everyday competencies?

Sample:Sample:• 242 Preschool (age 2.4 – 6.0 years) children

– Birth Announcements, preschools, health dept, word of mouth– Birth weight > 2500 g, – Reported Milestones WNL,– ~70% Caucasian (n=170), 30% Minority Race/Ethnicity (n=72)– 54% Female (n=130), 46% Male (n=112)

14.2100.9Estimated IQ

2.314.2Maternal Education (yrs)

10.04.0Child Age (years)

SDMean Variable

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Delayed Response (DR, adapted from Diamond, 1990)

DV : # of correct retrievals

Wells, Rewards, Cups to occlude wells, Active Delay

Delayed Alternation (DA)(adapted from Goldman, 1971)• Use reward information from

previous trial to guide response on next trial

• Search for the reward in the well opposite where last retrieved reward

DV = # correct retrievals

Spatial Reversal (SR)(Kaufmann et al., 1989)

•Hide reward out of child’s sight• After 4 consecutive correct retrievals at same location, reward is hidden at alternate location•Reversals continue after each set achieved

DV = # of correct retrievals

Spatial Reversal with Irrelevant Color Cues (SRC)(Espy et al., 2001)

• Hide reward out of child’s sight

• After 4 consecutive correct retrievals at same location, reward is hidden at alternate

• Reversals continue after each set achieved

• Colored cups move randomly between locations (fixed schedule) as a distraction

DV = # of trials to first set

Six Boxes – (6B-NS, 6B-S; Diamond et al., 1997)

•Place sticker rewards in each box•Child opens box on each trial•Scramble location between trials

during 10s delay•Non-Spatial: Use color/shape information

to retrieve stickers from each box•Spatial: Use location information for retrieval.

Dependent Variable:# of rewards retrieved/# boxes opened

Shape School (Espy, 1997)

Control Naming Condition

To set up prepotent responseMeasure baseline naming speed

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Shape School - Inhibit (SSI) Condition

DV = latency to completeSuppress naming response

Children’s Continuous Performance Test (C-CPT)(Kerns & Rondeau, 1998)

• Computer administered• Child hits mouse when target

animal appears• Ignores (does not respond) to

distractor animals

MOO

• Animals make sounds (randomized) that conflict withtheir identity

• 3 minute total time• DV=Hits / (Hits + Commission Errors)

Whisper (Kochanska et al., 1996)

•Child is shown picture book of 10 colorful characters that vary in salience

•e.g. Big Bird•Natural response is to shout name.•Child is instructed to whisper stimulinames.

• Score 2 if successfully whisper,1 if slip, 0=if shout

Standardized Instruments:

NEPSY Statue (ST)(Korkman et al, 1998)– Child maintains a fixed posture

for 75”– Examiner “entices” to move by

different maneuvers i.e. cough, drop pencil, knock,

E says “Ho, hum!”– Score each 5” epoch by

amount of movement• Keep eyes closed, no talking,

and no body movements

Ho hum!

• NEPSY Visual Attention (VA)– Random array cats

sheet only– Child stamps relevant

target arrayed randomly among other distractors

DV= (Hits – Commissions) / Completion latency

• DAS Digit Span (DSP, Elliott, 1990)• - Say ‘5-2-7’, child ‘5-2-7’• -2 digits per second presentation rate• DV = maximum # of digits recalled

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Inhibit /ResponseSuppression

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Reversal/Set Shifting

ConclusionsConclusions• Developmental differences evident on most tasks

– Reversal tasks exception – intradimensional nature?– Slower, later developing?

• Developmental patterns varied, i.e., age curves did not map onto specific executive function

• “All tasks use domain-specific stimuli, processing and skill, so every measure of WM capacity/executive control reflects both domain-general and domain-specific components (Kane & Engle, 2002)

…translated into psychometrics

Psychometric Approach: Common (true score) variance in performance to identify latent executive ability(ies)

ExecutiveExecutiveExecutiveExecutive

ExecutiveExecutive

ContentContent

ContentContent

ContentContent(Language)(Language)

(Inhibition/ (Inhibition/ MaintainenceMaintainence))

(Non(Non--verbal verbal perception, perception, Manual Manual Search)Search)

(Shifting)(Shifting)

(Maintenance/ (Maintenance/ Inhibition)Inhibition)

(Language)(Language)

Task 1Task 1 Task 2Task 2 Task 3Task 3

ExecutiveExecutive

(Inhibition/ (Inhibition/ Maintenance)Maintenance)

ContentContent(Manual Search)(Manual Search)

““TaskTask”” 44

Can executive control be defined as the Can executive control be defined as the common, common, underlying or unobservable underlying or unobservable

domaindomain--general process?general process?

⇒SEM to systematically test different a priori (theory driven) models of organization⇒Taking advantage of common test variance

⇒Include broad tasks of different demands to uncover the unobservable, domain-general executive process(es), which are not apparent in any psychometric instrument

Executive Control Models: FractionatedExecutive Control Models: Fractionated• EFs are inter-related, but

distinguishable– Differential neuroanatomical

distribution, dorsal/lateral v. ventral/medial

• Role of stimulus content or properties– E.g. spatial vs. non-spatial

• Role of mental processes or abilities– E.g. manipulation v. maintenance,

cognitive v. emotional, etc.

• EFA in children– Typically identify 3 - 5

constructs – Vary in label depending on

tasks included

• CFA in adults– Shifting Mental Sets– Working Maintenance of

Information– Inhibiting Prepotent Responses

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3 factor, EF model 2 Factor, WMIC model

3 factor, dual IC model Executive Control Models: UnitaryExecutive Control Models: Unitary• PFC cells selectively

respond to task unique, fluidenvironmental contingencies or contexts that are linked relationally to outcomes– Combinations of cue

presence, reward, response, rules, etc.

– Activation profiles change with altered task demands

• PFC activity is maintained during delay, with interference, and utilizes stored information in posterior cortext (that are not active during delays)

• Neuroimaging studies reveal significant overlap in activated sites across tasks with the following executive demands:

-Conflict/Interference-Maintain information over

time-Adaptive, flexible responding

and Difficulty, Salience, Expectancy, Novelty

Unitary Model Goodness of Fit Indices for Alternative CFA Models

6248.15.987.024.244450.094. 1 Factor Context Model

6259.28.992.019.324144.763. 3 Factor Dual IC Model 3

6252.92.986.025.244349.382. 2 Factor WMIC Model 2

7638.15.933.046.0056395.881. 3 Factor EF Model 1

BICCFIRMSEAp valuedfχ2Model

Generally well fitting models…Advantage is in model comparison for theory testing

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Comparative Fit of Nested CFA Models:

4.77

6.36

BIC difference

.3991.071WMIC Model 2 vs. Context Model 4

.09924.62WMIC Model 2 vs. Dual IC Model 3

p valuedfdifference

χ2

differenceModel Comparison

Model 4, the unitary factor model is preferred

Adaptive Context Dimension Model

ConclusionsConclusions• Adaptive context dimensions that invoke a unitary

executive control may better conceptualize the role of the prefrontal cortex, esp. in young children

• In preschoolers, conflict/interference & maintenance/storage are, at a minimum, intertwined at this age– What develops?

• Benefits of confirmatory statistical approaches

Program Aim: Program Aim: Does executive control in Does executive control in preschool children matter?preschool children matter?

• What is the developmental ontogeny of executive control?

• How is executive control organized?

• How is executive control related to everyday competencies?

• What are the sources of individual variation in executive control?

• How is executive control altered by various types of neuropathology?

Impulsivity: Self-Control Task (Kopp, 1982)

• Wrapped gift placed in child’s reach

• Child instructed to wait until examiner finishes some paperwork

• 2.5-minute delay• Can child wait to touch

the gift?

Impulsivity and EC

Individual differences in impulsivity were related to general EC, controlling for age: F (1, 239) = 24.19, p < 0.0001. -0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

Low (N=125) High (N=117)Self-Control

Com

posi

te E

F Sc

ore

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Real World Behavior Real World Behavior

• Maternal ratings of child regulatory behavior in the everyday setting– BRIEF-P subscales

• Working Memory Inhibitory Control• Planning Emotional Control

– Rothbart’s CBQ• Inhibitory control Impulsivity• Activity level Anger

– CBCL• Aggression

• Construct Validity issue…..

Emergent Mathematic AbilitiesEmergent Mathematic Abilities• WJ-R Applied Problems

– Subitizing, grouping like objects

– Counting & cardinal relations

– Simple addition & subtraction

– age graded items using Rasch scoring

– Applicable to children age 2+ years

Emergent MathematicsEmergent Mathematics

Can polymorphisms in the Catechol-O-Methyl Transferase (COMT),Dopamine Transporter (DAT), or Dopamine Receptor (DR) genes (e.g., DRD2, DRDR4) be linked to normal variations in executive control?

Dopamine Receptors

Catechol-O-Methyl Transferase

Dopamine Transporter

DADA DADA

THTH

PrePre--Synaptic Synaptic ------ll----Synaptic CleftSynaptic Cleft----ll------PostPost--SynapticSynaptic

DADA

LL--TyrosineTyrosine

metabolismmetabolism

Genetic bases of behavior: Dopaminergic Systemventral tegmental area

nucleus accumbens

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PrematurityPrematurity•Risk for adverse outcome = Continuum of severity

•Degree of prematurity – proxy for host of medical complications•Presence of brain injury, e.g. hemorrhages, cysts, etc.•Social Risk

Even among those of “low severity”, later born, higher weights ~ 20% evidence later academic and behavioral difficulties

Neuropsychological ProfilesNeuropsychological Profiles• Nonverbal skill deficits (e.g., Taylor et al.)

Visual motor integration, PIQ, spatial skills, attentionnonverbal executive functions

• Evident at school age & adolescence

• Work in preschoolers limited largely to intellectual outcome

• Given risk, can we identify such deficits earlier with developmentally appropriate measures– i.e., using developmental cognitive neuroscience paradigms to

parse nature of deficits

Sample:Sample:• 30 2- to 5-year-old

children born preterm,28-35 weeks gestation – NICU grads– Mean GA = 30.2 weeks,

Mean Birthweight=3.8 lbs (SD=0.9)

– Lower biologic risk– No IVH > I, Hydro, seizure,

BPD, NEC– 19F; 11 M– 83% Caucasian

• 66 2- to 5-year-old typically developing children born fullterm– Recruited from local

health department, daycares, etc.

– All birth weights > 2500 grams (M=7.5 lbs, 1.2 SD)

– milestones = WNL– 38 F; 28 M– 70% Caucasian

Data Reduction, Principal Components Analysis

(.75) Delayed alternation(.74) Six Boxes(.90) Visual attention

(.61) Children’s CPT(.58) Delayed response(.75) Self control(.69) Statue

(.65) Spatial reversal (colour)(.74) Spatial reversal

Working memory

Inhibition

Shifting

Group Performance Differences

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

Math** IC WM* SH

PretermFullterm

Age and covariate controlled

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Predicting emergent maths skillsPredicting emergent maths skills• Age controlled:

– Inhibitory Control 32%****– Working Memory 17%***– Shifting 1%

• Age and covariates (race, maternal education, child vocabulary) controlled:– Inhibitory Control 14%****– Working Memory 3%*– Shifting 0%

• Age, covariates, and other EF’s controlled:– Inhibitory Control 12%****– Working Memory 1%– Shifting 0%

Biological Basis…pH as index of hypoxia

WJ-R Mathematics

.04-0.45.23-0.25Child Age (years)

.040.51----Birth Gestational Age (weeks)

<.01**0.71.04*0.43pH

0.67

0.49

-0.15Beta

<.01**

.06t

.49p

----Birth Gestational Age (weeks)

.03*0.46pH

.840.04Child Age (years)pBetaVisual Attention

Environmental Lead ExposureEnvironmental Lead ExposureVLLE

– 2.46 ugm/dl– Mean IQ = 99.63– Mean Birth weight =

7.32 lbs– Mean Maternal

Education=13.8 yrs– Mean Family Income =

$22,100

LLE– 6.06 ugm/dl– Mean Birth weight =

7.40 lbs– Mean Maternal

Education=13.8 yrs– Mean Family Income =

$28,900

Set ShiftingSet Shifting

0123456789

Trials to first set

VLLE LLE

0

1

2

3

4

Sets achieved

VLLE LLE

**

Spatial Reversal with Irrelevant Color Cues

ConclusionsConclusions• Executive control matters…

– Supports behavior in real world– Predicts early academic proficiency

• Shared cognitive competency that is a platform for academic learning?

• Better control of behavior facilitates learning?

– Differs meaningfully among individuals• Biological (& social) contributions to variation• Different skills patterns with different medical conditions• Useful in identifying those at risk for academic difficulties?

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Contributors:Contributors:Sandra A. Wiebe, Tiffany Sheffield, Hua Fang, Christian

Stopp, Noah Clayton, and Paul M. Kaufmann, Ph.D., University of Nebraska-Lincoln

Theresa E. Senn, Syracuse University Melanie McDiarmid, University of OklahomaMartha L. Glisky, Seattle Pacific UniversityRebecca Bull, University of AberdeenJodi Huggenvik, David Gilbert, T. Jameson,M.F. Cwik,

M.M. Stalets, J. Martin, H. Kaiser, M. Banet, A. Johnson, SIU School of Medicine

Sponsors:Sponsors:Rita Rudel Foundation; Blowitz-Ridgeway

Foundation; NIMH R01 065668; NIDA R01 014661; NICHD P01 038051; NICHD R01 050309

Development of Executive EVR: Control in … canada/KimberlyEspy.pdfDevelopment of Executive Control in Preschoolers Kimberly Andrews Espy, Ph.D. •Could no longer hold down job;

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