Stress, Neural Systems,and Genetic Code

An Interview with Neuroscientist Judy Cameron

Science has demonstrated that positive intervention can benefit children of all ages. Does your research suggest an optimum time for intervention?

Yes. We have just finished an intervention experiment where we introduced adoptive mothers to infant monkeys that had been separated from their birth mothers when the infants were a week old. Then, when the young monkeys were different ages (between 1 month of age and 2.5 months of age), we introduced an adoptive parent to the infant to assess what difference that would make in the infant’s behavior. We found that if you introduce the adoptive mother after the infant has been separated about three weeks, the new mother quickly forms a bond that reverses much of the anxious or detached behavior we see in separated animals. The young now develop the ability or desire to seek normal social contact.

We also found if you wait until the young monkey is two months of age to introduce an adoptive mother, the adoptive mother will not be able to reverse the damage. Although children’s brains continue to develop throughout childhood, and children can benefit from positive interaction through their teen years, our findings underscore the importance of thinking carefully about what happens to young children taken by society from parents for whatever reason—because of parental drug abuse, incarceration, maltreatment, or what have you. If these children could be moved into a more permanent, more nurturing situation right away, they would certainly benefit. The quality and timing of that placement is going to matter a great deal in how lasting are the effects of this stress.

But when we talk about the impact of stress, we have to be very clear about our terms, and how they apply in each situation. We have to remember there are different forms of stress, and very importantly there are individual differences in response to stress. Some severely stressful experiences certainly can lead to undesirable long-term outcomes, especially when there are no supportive relationships to help a child cope. The Council has termed such experiences “toxic stress”. Scientists suspect that different neural systems have an increased sensitivity to stress at different times during early development. A stressful experience early in life that is severe enough to be described as “toxic” can affect a child’s long-term social behavior in different yet predictable ways. As we learn more about brain architecture and we are better able to recognize which experiences weaken the evolving structure and make individuals more susceptible to the long-term effects of early life stress, we will be able to more adequately counteract those influences through better human interactions, including therapy, applied at the right time. In the final analysis, the goal is to use our growing knowledge to strengthen the foundation on which healthy brains are built and long-term developmental competence is achieved.

The interviewer: Dean Stahl is a researcher and writer, and co-author of Abbreviations Dictionary (CRC Press), a desktop reference and one of the most extensive English-language collections of abbreviations. Also the author of “Dolphins” (Child’s World Inc., 1991), he is a longtime contributor to Pacific Northwest magazine. He worked for several years as an editor at The Seattle Times.

For information about commonly used terms in Council publications, see Definitions.