What We’ve Learned About The Child Brain

Since he first began studying the brain in stroke patients using functional magnetic resonance imaging, or MRI, cognitive neuroscientist Damien Fair has become a star in the field of pediatric and adolescent brain development. His work has led to a greater understanding of mental health disorders and the impact of trauma, including intergenerational trauma, on the young brain. 

Last fall, Fair was named as one of the 2020 MacArthur “genius” award winners for his work in mapping network connectivity in individual brains to understand how they develop, an honor that comes with a no-strings-attached, $625,000 grant. He has not decided exactly how he’ll use the grant funds, but is planning to team up with his wife Rahel Nardos, a urogynecologist and the director of the women’s global health department at the University of Minnesota, to combine their expertise on infant brain development and maternal health. They also hope to do work on capacity building in marginalized communities across the world and diversify the workforce in STEM fields. 

Fair is the director of the Masonic Institute for the Developing Brain at the University of Minnesota. The Imprint talked to him about the growing base of knowledge we have about the child brain, and what the implications are for child welfare policies. The interview has been edited for brevity.

A focal point of your work has been understanding ADHD and Autism Spectrum Disorders. What do we know today about these disorders that we didn’t know 10 or 20 years ago? 

One of the bigger shifts in the field across both disorders is that these disorders that we label as ADHD or autism … are not really single disorders at all. They’re likely multiple different disorders that have very unique and distinct mechanisms inside the brain. 

An example I like to give goes back to my clinical days when I was working in the ER and seeing patients with acute stroke. Someone would come in and they would have difficulty speaking. They’d have facial droop. They’d have difficulty moving one side of their arm. So you knew they must have had a stroke because the symptoms were so clear. But we don’t treat them right away because we need to know whether what’s causing those symptoms is coming from an ischemic stroke, where you have a blood clot, or a hemorrhagic stroke, where they’re having a bleed. You can imagine the way you treat those things are completely opposite. 

A lot of mental health disorders are all based just on the symptoms. It’s just like having the facial droop (for stroke patients). But what we and others have been able to show pretty clearly is that inside the brain, just like stroke, people can have the same outward appearance, but the reason why they’re having it can be completely different. So if we’re going to develop therapies and make better diagnoses, we need to understand a lot of the mechanisms occurring in the brain. 

In layman’s terms, how do you approach the study of young brain development?

Most people are familiar with traditional task MRI, where you put someone in an MRI scanner, and then you have them do some task, and you see parts of the brain become active. What we do is resting state functional connectivity MRI, which was discovered by Bharat Biswal back in 1995. 

You have them move their fingers and then rest and then move their fingers and then rest over and over again, and you can identify the parts of the motor cortex. Then Biswall said, “I’m going to have you go into the scanner and sit there at rest and not do anything at all. Just sit. Don’t move.” 

What he found was that the same brain regions that were popping up and down when you’re moving your fingers were also sitting there correlating with each other when you’re at rest. That told us that the signal we usually average out of our task MRI studies is not noise at all, but it’s actually a functioning relevant signal that tells us about how different parts of the brain are communicating with each other over time. So we use this technique to look at the idling brain and study how the different parts of the brain are communicating and seeing how that changes as a function of age. 

You emphasize that understanding diversity and variability is key in studying brain development. So much of government support for mental health and behavioral services is based on approved models and eligibility criteria. How do we tailor an array of services to the child? 

We think about this a lot. It is a struggle because our institutions are designed on a model where everybody’s average. And we know that that’s just not true. It’s like fighter pilot seats. When they first started making these, they took measurements of the height and arm length and the leg length, and they generated a fighter pilot cockpit that would be best for everybody because it was based on the average. What they found is it didn’t fit anybody because nobody’s average. 

A lot of our institutions have been built on a similar structure where we develop policies and therapies and processes based on what’s best for the average. At our new institute, the Masonic Institute of the Developing Brain, we build mathematical models where you take a group of kids with all these different types of features, just like the cockpit example, from executive function to clinical diagnosis to home environment to past history. They have all these features and an outcome that you want, like you want them to get into college. 

We generate a model that helps you figure out, for a given program or intervention, what are all the different patterns of kids that will fit best into that bucket to get them to college? It’s information for the applied folks who are actually on the ground doing work to assist in making the best choices for that child. 

Is there a state, county or organization you know of that’s really figured this out?

Not yet. I’ve been doing this type of research for a long time, but the access to the right folks has always been a problem. It’s one of the main pillars of why I’m here at the University of Minnesota and why I’m co-directing this new institute. Even though there’s all these ideas and tools that could help policymakers and providers, we’re often so stuck in our own little silos that getting the information from me to this person or that person is just too slow. 

If I make a new discovery today, it will take 17 years or more to get into something applicable for a patient or to a family. That’s just too long. What we’re trying to do with the new institute is to develop systems so that information gets transferred much faster.

Have you specifically studied the impact of abuse or neglect on the young brain? Does that generally differ from other types of trauma that young people experience? 

We have focused on a couple areas of childhood trauma. The bigger and more important one is what we call intergenerational transmissions. It turns out that the effects of abuse and neglect and other childhood trauma, particularly to women, can manifest in offspring later on. The effects of early childhood abuse and neglect last not just the lifetime of the individual but into generations — and that’s a big deal. 

The question is, how does that happen? We think that the immune system has a part to play. The immune system typically keeps you from getting sick, but it has a lot of influence on how our brain develops, too. A lot of the cells that are usually cleaning up viruses help to sculpt our brain synapses, too. If that goes awry or there is overactivity or underactivity, then that has an effect on the brain and behavior long term. 

Our hypothesis is that pregnancy is, in some sense, a stressful event. There are a lot of metabolic and physiological changes that occur during pregnancy and there is likely a change in the immune response during pregnancy that may be related all the way back to the childhood trauma. That immune response during pregnancy may have an effect on the developing brain of the fetus and into infancy, and that’s one of the mechanisms by which we believe that we’re testing the intergenerational effects of abuse and neglect. 

Tell me about your work on the effects of early life environmental influences and childhood experiences. 

I’m not necessarily the expert on this, but I have several colleagues who are really in the weeds. Childhood adversity has a lot of effects on the part of the brain that is important for emotion regulation, called the amygdala. So we’ve actually used this functional connectivity technique to highlight how early childhood adversity has long-term effects on these circuits that are important for emotional regulation. 

We also know that childhood adversity is often tied or linked to poor nutrition, which has a significant effect on the immune system. Even in kids, it starts to make it look like they’re chronically ill as far as the immune system goes. Because the immune system is related to brain development, we know that poor nutrition has a very large effect on long-term outcomes. 

What are some of the benefits of early intervention when it’s discovered that a child has unique atypical brain function? 

The brain is extremely plastic and the further back you go, the more malleable it is. We have a huge focus on the first 1,000 days to identify atypical trajectories for earlier intervention. 

The way that the brain develops is kind of counterintuitive to how folks typically think of development. We typically think about development as like building a house. You have a foundation and then you build up the studs and the walls and then you put the roof on and then you start adding stuff. The brain develops more like you’re building a sculpture. In essence, by the time you’re born, almost all the neurons you’re ever going to have in your life are in place. Then shortly around the age of 1 or close to 2, you have this proliferation of connections across the entire brain. All of the sudden you have all the neurons you’re going to have and the most connections you’ll ever have in the brain. 

Then over time, you start whittling away at all those connections. You’re sculpting what you’re going to look like as an adult. That’s one of the reasons why starting early is so important. 

California is moving forward with a goal of screening most children for ACES (adverse childhood experiences) as babies. The original ACES study was a look backward, studying adults to see what impact child trauma had on them. Do you think screening proactively for ACES is a good idea? 

I think it’s a good idea to understand and be able to collect information. The worry, of course, is that it has to be done in a way that is not biased or skewed because of some of the structural issues that we have with regard to marginalized communities and folks who are disenfranchised. 

The other piece here is that it’s one thing to screen, but how are you intervening and what does that mean for the long term? Answering all those questions is an important aspect of such a program. 

There are some youth advocates who believe that either the age that youth are incarcerated in the juvenile justice system should be raised to include older teens and those in their early 20s, or that a separate young adult justice system different from the typical criminal justice system should be established. Does this line up with what you know about the young adult brain? Is it more like that of a youth than it is like that of an adult?

I was part of a group from the MacArthur Foundation on this topic, and I don’t know if we ever came to a final conclusion. The arbitrariness of 18 as this cutoff is probably not based on science about how the brain develops. But how to make a cutoff is a big question, probably more than I could answer today. The way they make the cutoff and whether the brain is fully matured or not is causing disparities in the system. 

A lot of times, you enter into the juvenile justice system when you’re in some emotional confrontation or conducting risky behavior with friends. So then the question is, in that state, what does the brain look like? We set up this experiment where we could measure some of this brain connectivity as a function of different emotional states. What happened was fascinating. Some kids’ brains would look like they’re older. Some kids’ brains would look like they’re the same. Some kids’ brains would look like they’re younger. What we found is that if you were somebody whose brain went backward and looked younger, you were at risk of being risky. 

The part that was even more fascinating was that young adults and adolescents were the ones who were more likely to go backward. You would see as you’re moving to adolescence, you’re more likely to look younger and be more at risk of being risky. As you age into the late 20s, then it starts to come back. That’s just one of the experiments that we did trying to answer those very difficult questions.