The effect of the COMT gene on executive functions in young children
In a new study published in Developmental Science , Yusuke Moriguchi from the Graduate School of Education and collaborators found that the gene Catechol-O-methyltransferase ( COMT ) plays a role in developing cognitive 'executive functions' and prefrontal activation of preschool-aged children.
Multiple socioeconomic and environmental factors in upbringing contribute to healthy cognitive development in children, but how about genetic or biological factors?
One such predictor of cognitive development is the ability to control thoughts and actions, also known as executive function (EF). Research in adults has shown that the brain's lateral prefrontal cortex, and the neurotransmitter dopamine are key players in 'proper' EF.
This led researchers to gene that contributes to the degradation of released dopamine, COMT . Previous studies had shown that variants in this gene are associated with behavioral and performance activations in EF tasks. However, the effect of the COMT gene and EF tasks in young children had yet to be examined.
The team focused on a common alteration in COMT , where the 158th amino acid Valine is changed to a Methionine.
To test for EF in developing minds, the team gave groups of children a rule-switching task, where participants sorted cards based on color or shape. In a 'pre-switch' phase, children sorted cards according to one rule, such as color. Then in a 'post-switch' phase, they employed a second rule, such as shape. Moreover, in a mixed phase, they needed to switch both rules. These tests assessed how efficiently the children could switch rules. At the same time, the team examined activity in each child's lateral prefrontal cortex.
Compared with children with at least one Met allele, Val homozygous children showed increased activation in the lateral prefrontal cortex during the task, and appeared to show more flexibility when switching between rules. Interestingly, the effects on behavior were observed only in 5- to 6-year-old children.
Moriguchi states that, since EF is the ability to control thoughts and actions, identifying what factors affect its difference during childhood is a valuable research topic. In fact, several studies have shown that EF development during childhood can be a predictor for the quality of achievements and relationships in adolescent and adult life.
However, it must be noted that these results do not indicate that a child's EF is determined by genes. Rather, a combination of genetics, environmental factors, and parenting during early childhood are the key determinants.
The next question the team wants to address is the varying effectiveness of different parenting and education techniques depending on a child's genotype. At the same time, they intend to continue looking for other candidate genes that affect EF.
Experimental design. Test cards and target cards designations change depending on the rules given (Moriguchi Lab, Kyoto University)
【KURENAI ACCESS URL】 http://hdl.handle.net/2433/228368
Yusuke Moriguchi, Ikuko Shinohara (2018). Effect of the COMT Val158Met genotype on lateral prefrontal activations in young children. Developmental Science.