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PMID 18180765

MANUSCRIPT ID

• Title

Executive Functions are almost entirely genetic in origin

• Reference

Friedman NP et al, 2008

• Abstract

The human genome project has stimulated development of impressive repositories of biological knowledge at the genomic level and new knowledge bases are rapidly being developed in a bottom-up fashion. In contrast, higher-level phenomics knowledge bases are underdeveloped, particularly with respect to the complex neuropsychiatric syndrome, symptom, cognitive, and neural systems phenotypes widely acknowledged as critical to advance molecular psychiatry research. This gap limits informatics strategies that could improve both the mining and representation of relevant knowledge, and help prioritize phenotypes for new research. Most existing structured knowledge bases also engage a limited set of contributors, and thus fail to leverage recent developments in social collaborative knowledge-building. We developed a collaborative annotation database to enable representa- tion and sharing of empirical information about phenotypes important to neuropsychiatric research (www.Phenowiki.org). As a proof of concept, we focused on findings relevant to cognitive control, a neurocognitive construct considered important to multiple neuro-psychiatric syndromes. Currently this knowledge base tabulates empirical findings about heritabilities and measurement properties of specific cognitive task and rating scale indicators (n = 449 observations). It is hoped that this new open resource can serve as a starting point that enables broadly collaborative knowledge-building, and help investigators select and prioritize endophenotypes for translational research.

• Keywords

phenotype; cognition; heritability; genetics; cognitive control; informatics

• Input Author

fws

MANUSCRIPT DETAILS

• Introduction/Aims

A figure that details the phenomics strategy that looks a multi-variate and multi-level phenotypes

What are ‘executive functions’

‘an ability for individuals to control their own thoughts an actions’

Unity and Diversity of EF

initially thought of as a unitary construct

most thought of now is at least three (inhibit, update, shift)

most tasks are ‘impure’: one solution...use latent variables

Twins

Allow examination with fancy stats to see additive (a), common environment (c), and nonshared environment (e)

• Method

ACE modeling of twin data

Participants

582 folks from 293 same-sex twin pairs (colorado longitudinal twin study)

316 MZ twins (177 female)

266 DZ twins (137 female)

age=16 or 17 ??

IQ mean =102, sd =11

Tasks

Inhibiting

Antisaccade

StopSignal

Stroop

Updating

keeptrack

lettermemory

spatial 2back

Shifting

letter-number

color-shape

category

WAIS and some perceptual speed measures too

• Results

Velocity of the use of the term cognitive control in the published literature over the last ten years in comparison to similar latent constructs (including working memory, response selction, task-switching)

Heatmap of pairwise searches of latent constructs. Jaccard value is a measure of co-occurence

Cognitive Control construct and related concepts and tasks. Thickness of circles represent literature size and distance from cognitive control label represents co-occurence frequency

Table of findings for heritability of construct

• Discussion
  • Executive functions show overwhelming strong genetic influence, and its not all related to a primary 'g' factor
  • Implications for future research using endophenotypes, latent variable approaches, and the search for the neurobiology of complex behaviors