Inside the brain: What MRIs are teaching us

Have you ever wondered what’s going on inside your child’s brain when he’s struggling to learn? If so, you’re not the only one. Scientists are starting to use a type of brain scan known as an fMRI to get a better idea of what’s happening in the brains of kids with learning and thinking differences.

What is an MRI?

Doctors have used magnetic resonance imaging (MRI) scans since the late 1970s as a way to get a better view of what’s going on inside the body. MRI machines use a magnetic field and pulses of radio wave energy to make a computerized map of the part of the body being scanned. MRIs provide a clearer image of many body parts compared to an X-ray.

“Researchers are learning a lot by comparing the scans of people who don’t have learning or thinking differences with scans of people who do have them.”

Researchers have compared hundreds of scans of people of various ages and stages of health. This has given them a good idea of what a “typical” scan looks like. As a result, researchers can now tell whether parts of a person’s brain look different than expected.

What is an fMRI?

In the late 1990s, researchers discovered that MRIs could be used to look not only at the structure of the brain, but also at how it functions. This technology is known as functional magnetic resonance imaging, or fMRI. Here’s how it works:

• The blood in our bodies contains varying levels of oxygen. Some blood is oxygen-rich and some is oxygen-poor. These types of blood respond differently to the magnetic field in an MRI. Oxygen-rich blood responds with more strength and shows up as a stronger signal on the scan image. It looks brighter or bolder.

• When a part of the brain is active, the brain cells (neurons) cause a change in blood flow. That causes an increase in oxygen-rich blood in that area of the brain.

So, the part of the brain that’s active receives more oxygen-rich blood than less active areas. That shows up on a brain scan as a bolder, brighter image. This allows researchers to look at which part of the brain is active when people are doing different types of tasks.

How does fMRI work?

An fMRI scan starts by taking images of the brain at rest. Those are called baseline images. The next step is to look at the brain while a person is doing something. This could be trying to solve math problems, reading, answering questions, looking at pictures or doing other tasks. This allows researchers to see which areas of the brain are getting more oxygen-rich blood.

What can fMRI teach us about learning and thinking differences?

Researchers are learning a lot by comparing the scans of people who don’t have learning and thinking differences with scans of people who do have them. They’re able to see which areas of the brain are typically active during reading, writing, math and concentration.

They can also see what’s not happening as expected in the brains of people with learning and thinking differences. Here’s some of what they’ve learned so far:

• The part of the brain that deals with language processing works differently in children who have dyslexia.

• An area of the brain called the prefrontal cortex, which helps with executive functioning and attention, develops more slowly in children with ADHD.

These differences don’t mean kids with learning and thinking differences are less intelligent than their peers. In fact, they usually have average or above-average intelligence.

Being able to look at what’s going on in the brains of kids with learning and thinking differences helps researchers learn more about the potential causes. Researchers also hope it will provide a way to identify learning and thinking differences earlier. For now this kind of research gives us all a better idea of how the brain plays a role in learning.