July 17 (HealthDay News) -- Whether you have an easy baby or a fussy one may have nothing to do with your parenting skills because the combination of a certain gene and a particular pattern of brain activity may determine a child's temperament, a new study has found.
Canadian researchers examined the interaction between the DRD4 gene and activity in the frontal cortex of the brain to find out if it predicted children's temperament.
Previous studies have suggested that the longer version (allele) of the DRD4 gene is associated with increased sensory responsiveness, risk-seeking behavior and attention problems in children. It has also been determined that infants with more activity in the left frontal cortex are temperamentally "easy" and take little effort to calm down. On the other hand, children with more activity in the right frontal cortex are more easily distressed, more difficult to soothe, and are considered to have a "negative" temperament.
In this study, Louis Schmidt of McMaster University in Hamilton, Ontario, and colleagues measured brain activity in 9-month-old infants. When the children were 4 years old, their mothers completed questionnaires about their children's behavior, and DNA samples were taken from the children for analysis of the DRD4 gene.
The researchers found that children who had more left frontal cortex activity and had the long version of the DRD4 gene were more easily soothed at 48 months than those with the shorter version of the gene. Children with the long version of the gene and with more activity in the right frontal cortex were the least soothable and had more attention problems than the other children, according to the study.
The findings "suggest that it is possible that the DRD4 long allele plays different roles (for better and for worse) in child temperament," the researchers said. They added that the pattern of frontal cortex activity may influence how DRD4 affects a child's temperament.
The study appears online in the journal Psychological Science.
SOURCE: Association for Psychological Science, news release, July 13, 2009