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Hush Little Baby… Linking Genes, Brain and Behavior in Children

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It comes as no surprise that some babies are more difficult to soothe than others but frustrated parents may be relieved to know that this is not necessarily an indication of their parenting skills. According to a new report in Psychological Science, a journal of the Association for Psychological Science, children’s temperament may be due in part to a combination of a certain gene and a specific pattern of brain activity.

The pattern of brain activity in the frontal cortex of the brain has been associated with various temperaments in children. For example, infants who have more activity in the left frontal cortex are characterized as having “easy” temperaments and are easily calmed down. Conversely, infants with greater activity in the right half of the frontal cortex have “negative” temperaments and are easily distressed and more difficult to soothe.

In this study, Louis A. Schmidt from McMaster University and his colleagues investigated the interaction between brain activity and the DRD4 gene to see if it can predict children’s temperaments. The longer version (or allele) of this gene has been linked in a number of studies to increased risk-seeking behavior and attention-related problems in children. In the present experiment, brain activity was measured in 9 month old infants via electroencephalography (EEG) recordings. When the children were 48 months old, their mothers completed questionnaires regarding their behavior and DNA samples were taken from the children for analysis of the DRD4 gene.

The results reveal an interesting relationship between brain activity, behavior and the DRD4 gene. The children who exhibited more activity in the left frontal cortex at 9 months and had the long version of the DRD4 gene were more soothable at 48 months compared to children with more activity in the left frontal cortex who possessed the shorter version of the gene. However, the children with the long version of the DRD4 gene who had more activity in the right frontal cortex were the least soothable and exhibited more attention problems compared to the other children.

These findings indicate that the long version of the DRD4 gene may act as a moderator of children’s temperaments. The authors note that the “results suggest that it is possible that the DRD4 long allele plays different roles (for better and for worse) in child temperament as a function of endoenvironmental conditions” and conclude that the pattern of brain activity (that is, greater activation in right or left frontal cortex) may influence whether this gene is protective or is a risk factor for attention problems.