New Windows on Our Minds
Our
brain is a wonderful and complicated organ. And scientists
have been working for centuries to understand how it works.
In recent years, they have discovered new ways to study the brain. Scientists can now watch the activities of different parts of our brain while it is at work. We can think of these techniques as new windows on our minds.
One new research method is called fMRI. It can take pictures of your brain in much the same way as an X-ray machine can take pictures of your bones. This method makes use of the fact that whenever a part of your brain becomes more active, it uses more oxygen.
If someone were to use this technique to study your brain, your head would be surrounded by a device that includes a big magnet. This device can detect tiny signals coming from oxygen. With the help of a computer, it turns these signals into pictures. By taking pictures every few seconds, scientists can tell which parts of your brain become active when you think of something, such as multiplying three times ten.
Memory
Storage
Storing memories is one of the most important jobs our brain
does. Without stored memories, we would not be able to recall
new words we have learned or find our way home.
Everything we learn must be stored as memories in our brain. And storing a memory requires that something somewhere in our brain changes. Once a change is made, it must remain, even after the effort to learn has stopped. If the change doesn’t remain, we will forget what we’ve learned.
Like
the memory in our computers, most of our memories are stored
away out of our awareness. But when we need them, they can
be “copied” and temporarily placed in what is
called our “working memory” for immediate use.
Dr. Yang Jiang is one of the scientists using fMRI to learn
more about how the brain works. She works in a laboratory
at the National Institute of Mental Health in Bethesda,
Maryland.
Where
Do Memories Live?
Dr. Jiang told me that she and her colleagues wanted to
know more about where in the brain our working memories
were kept. So they asked this question: where do we store
the memory of a face we are looking for when we are surrounded
by people we know?
For example, which parts of your brain are activated when you are at your brother’s birthday party and want to find your mother in a room filled with other relatives? And then, once you’ve spoken to your mother, what happens when you want to find your brother to give him a gift?
Dr. Jiang and her colleagues learned that when you want to search for your mother, you first put your memory of her face in one part of your working memory. This is the part that has the job of remembering who it is you are looking for. And this part is found near the front of your brain.
The memories of the other familiar faces, such as your brother’s, are kept in another part of your working memory. This part is located near the back of the brain and has the job of letting you ignore the faces of people you are not seeking. When you see your mother’s face, you activate those areas of your brain that control your movements toward her.
Next you want to give your brother the gift you brought for him. Now his face will replace your mother’s face in the part of your brain’s working memory that has the job of remembering the person you are seeking.
Mind-Reading
Machines?
Does all this research mean that we will soon be able to
read others’ minds and know what they are thinking?
Most likely not, but for scientists like Dr. Jiang, there
are plenty of exciting experiments to do to learn more about
how the brain works.
Here is one of the next questions Dr. Jiang wants to ask:
how does the brain perceive complex motion? This is like
asking how an outfielder knows where to run to catch a
baseball that is flying through the air.
If you were a scientist who studies the brain, what questions would you like to ask?
