Grant: CIHR New Investigator

A number of studies have shown that individuals born to mothers who were exposed to severe stressors during pregnancy are at increased risk of developing psychological problems later in life. The brain chemical serotonin may be important in this process. Animal studies have shown that adversity during pregnancy can alter the activity of serotonin and the function and structure of brain regions playing a role in the regulation of emotions in the newborn. These alterations can persist until adulthood. In the proposed project, we will investigate whether these long-lasting alterations also occur in humans. To study this, adolescents will undergo a brain scan (called fMRI) while viewing faces with emotional expressions. This is a standard procedure to measure, in the laboratory, how the brain reacts to situations that elicit emotions. Adversity will be indexed by birth weight since lower birth weight is indicative of greater adversity during pregnancy. We expect that birth weight will predict the function of those parts of the brain that are important in emotion regulation. We will also investigate one of the mechanisms by which adversity during pregnancy may affect the brain: via changes in gene expression. One of the genes that we will look at is the serotonin transporter, a gene that determines how much serotonin is used in the brain. These questions will be examined in twin pairs that have been followed almost yearly since they were born. We hope that this project will increase our understanding of the specific role of early environmental influences on brain development, gene expression and mental health. Results should eventually lead to a better understanding of possible early ways to foster optimal brain development and prevent mental health problems.