Rebecca Saxe – Cognitive neuroscientist
When you look at this picture, what do you see? This picture is an MRI image of a mother and her child that I made in my lab at MIT. You might see it as sweet and touching, a kind of modern Madonna, an image of universal love. We can’t see clothes or hairstyles or even skin color.
From what we do see, the biology in the brains, this could be any mother and child, or even father and child, at any time and place in history, having an experience that any human could recognize. Or you might see it as disturbing, a reminder that our human bodies are much too fragile as houses for ourselves.
MRIs are usually medical images and often bad news. Each white spot in that picture is a blood vessel that could clog. Each tiny fold of those brains could harbor a tumor. The baby’s brain maybe looks particularly vulnerable, pressed against the soft, thin shell of its skull. I see those things, universal emotions, frightening fragility, but I also see one of the most amazing transformations in biology and one of the hardest problems for science. Where do we come from?
Less than a year earlier, that baby’s brain was a tiny clump of cells, basically similar to the clump of cells that would become the brain of a mouse or a fly or a sea slug. And then some combination of biological machinery and environmental experience taught those cells how to develop into a human baby’s brain and then a human adult brain with all the special human capacities for language and empathy and morality.
So I suggest that if we want to understand the human mind, we have to start at the beginning and study the brains of babies because the answers could unlock so many mysteries, like: how much of what we see and think and feel about our world is universal, shared with all human beings, and how much is unique, specific to each one of us? How do learning and experience change who we are?
By studying the brains of babies, we could literally see the beginnings of ourselves. And those are big, abstract, even philosophical questions, but this research would have concrete payoffs too, in understanding the brain’s vulnerability and its resilience. Probably everyone in this room has loved someone with brain damage. I do. My grandmother has Alzheimer’s disease. My grandfather had Parkinson’s disease. My father had a stroke.
In an adult, most brain damage is permanent, but baby brains are more adaptable and can compensate for many kinds of damage. And if we knew how that worked and could bring some of that adaptability to the adults, imagine the difference we could make in our lives.
On the other hand, babies’ brains are vulnerable and might contain the signs of later problems, like autism or dyslexia or depression. And we’d like to be able to catch those signs early and do something before the child has to fail or suffer. Those goals are part of why I am a scientist, part of why I keep going to work in the morning. I study human brain development because I want to understand how the human mind is built and maybe be able to help fix it when it’s broken. That’s the distant horizon but it could be very distant.
We still really know almost nothing about human baby brains, and that’s because studying the brains of babies is really hard. Now, human babies are a hard population to study at the best of times. Compared to human adults, they don’t follow instructions, and they burp and poo and fall asleep during your experiments. Compared to mice and flies and sea slugs, they are hard to breed.
Studying the brain adds extra challenges, and that’s because the best tool to study human brain function is an fMRI. An fMRI is a recording of brain function; it lets us watch blood flow through the brain, bringing the oxygen that it needs to work. So while you’re sitting here, oxygenated blood is flowing through your brain, and it’s going to different places if you’re listening to what I’m saying or looking at my face or just daydreaming about what you did last night.
fMRI is a neuroscientist’s dream come true. Just 20 years ago, before fMRI, looking inside someone’s brain was dangerous and rare. It happened during surgery, as a result of injury, or after death. And the picture that it gave us of human brain function was like a blurry snapshot. When I started trying to become a scientist, fMRI had just become available, and we felt like suddenly we could make gorgeous, high-definition movies of anyone’s brain doing basically anything, like language and empathy and morality. That’s the research I do in adults.
And for the last eight years, I’ve been gearing up to use the same tool to study the brains of babies. Eight years is by far the longest I’ve ever spent working on a single experiment, and that’s because using fMRI and babies brings a bunch of extra challenges.
First of all, the baby needs to be still. Even though we’re using a cutting-edge machine, it can feel like we’re trying to take a picture in the 19th century. If you move at all while we’re taking the picture, all we see is a blur. To give you a sense of this, for any parent in the room, think about a family photo shoot, trying to get your 6-month-old baby to smile for the perfect photo.
Now imagine she had to hold that exact smile, moving less than a millimeter, for eight minutes. Second, the baby needs to be awake. The whole point of this experiment is that we’re trying to study how the brain experiences the world, so we need to give the baby an experience of the world whilst shoved inside the tube of an MRI machine. So we do that by showing them movies of the kinds of things they like to look at anyway in their everyday lives, like moving around in their neighborhoods or the smiling faces of their friends.