The project’s researchers hope their findings will aid the development of new intervention strategies for helping both mothers and children, and prove valuable to others working in fields such as drug abuse and developmental disorders.
Josephine Johns, Ph.D., associate professor of psychiatry and psychology at UNC, is the principal investigator and project director of the study. Linda Mayes, M.D., professor of child psychiatry, pediatrics and psychology at Yale, is principal investigator for the portion of the study conducted there.
“The scientific tools and methods developed and used for the project, as well as the new information it will provide about the basis of maternal-infant interactions, should prove beneficial for behavioral or biological intervention strategies,” Johns said.
“For example, if specific types of cries are found to elicit negative feelings or responses from mothers, on a very basic level we can work with mothers to make them aware of why these cries might be uncomfortable and develop methods for coping and responding to their babies in a more positive fashion,” she said.
The study will consist of three separate projects, supported by shared neuroimaging and data analysis teams. Project 1, based at UNC, will examine the effects of cocaine on mother-infant interactions in rodents. Researchers will examine the brain development of infants exposed to cocaine and how that exposure affects their ability to regulate body temperature, hormones and other bodily processes. The project will also determine how cocaine use during pregnancy affects mothers’ brain structures and hormonal systems, alters their genetic responses and affects how mothers respond to specific kinds of cues from their babies, such as cries.
Projects 2 and 3 will study similar measures to Project 1, but will focus on human pairs of mothers and infants, including mothers who used cocaine during pregnancy and those who did not. Project 2, also based at UNC, will examine mothers’ emotional and hormonal responses when feeding and cuddling their infants, and to baby-related cues such as cries and pictures of babies. Researchers will also study how cocaine exposure during pregnancy affects babies’ early brain development, whether their cries have different sound characteristics, and behavioral factors that may affect mother-infant interaction.
Project 3, which is based at Yale, will focus on using functional brain imaging scans, or fMRI technology, to study how mothers’ brains react to many of the same stimulus cues used in Project 2, as well as how particular genes may modify key aspects of early maternal sensitivity to infants’ cues.
“Understanding, for example, how genes and experiences such as substance use come together to influence how a mother responds to her baby’s cry or other expressions of distress sets the stage for working towards finding innovative interventions for adults who are struggling to care for their children under the burden of their own substance use,” Mayes said.
All studies will also focus on the role of the hormone oxytocin, which has been identified as playing an important role in human child birth, production of breast milk and response to stress, and has also been directly associated with early maternal care and social behavior in laboratory rodents. Previous studies in Johns’ lab found that rodent mothers exposed to cocaine during and just after pregnancy provided poorer care to their pups, which correlated with disruptions of the oxytocin system.
The research team includes more than 30 members from UNC, Yale, the University of Utah and several other universities. Work will take place primarily at UNC, Yale, Carolinas Medical Center in Charlotte and the Brain Body Center at the University of Illinois at Chicago.
The study is funded mainly by the National Institute on Drug Abuse, with additional funding from the National Institute of Mental Health and the National Institutes of Health’s Directors Office of Behavioral and Social Sciences.