Close your eyes and carefully follow instructions for a few minutes. (Yes, you can open your eyes to read, but then close them when necessary!) Imagine a large dragon flying lazily through the air above a large castle on a sunny, spring day. Can you see it in your mind's eye?
Now close your eyes and think of one of your favorite friends or relatives. Replay your favorite memory with that person. Did you go camping with them and encounter a bear? Perhaps you went skydiving or whitewater rafting?
Why did we have you do these imagination exercises? We wanted to show you just briefly how amazing your brain is. You've never seen a dragon. You might not have ever seen a live koala bear or kangaroo either. But that doesn't stop your mind from generating vivid pictures inside your head of the scenes we described.
Your brain also can do math and replay complex memories from years ago. And guess what? It can do so much more! There's virtually no limit to the thoughts you can think. But exactly how do you do that thinking?
Scientists who study the brain will tell you that's a question that's nearly impossible to answer. Despite all of our advances in science over the years, we've made remarkably little progress in using our brains to study our brains to figure out exactly how our brains create and process thoughts!
Fortunately, many scientists continue to study the brain, trying to unlock its secrets. Modern technology is helping their pursuit of knowledge. For example, magnetic resonance imaging (MRI) machines can now be used to monitor and measure electrical activity in the brain.
Using MRI machines, scientists can detect which parts of the brain are active during a variety of activities. Scientists know that different parts of the brain are active when you imagine seeing an ice cream cone compared to when you think about what it tastes like.
Likewise, doing complex math problems will activate different regions of the brain than reading novels or watching television. But knowing a bit about which regions of the brain seem to handle different thinking tasks only helps us to narrow down areas where activity is occurring. It still doesn't tell us what happens in those areas.
Current research suggests that thoughts arise through the complex interactions of the brain's billions of nerve cells called neurons. Neurons interact with each other via dendrites and axon terminals, which are branch-like tentacles that surround neurons. Neurons can transmit and receive electrical nerve signals at speeds approaching 200 miles per hour.
Some experts believe that neurons come together to form an intricate net, known as a neuronet, in order to form thought patterns. Their dendrites and axon terminals never really touch, though. Instead, electrical nerve signals pass from one neuron to the next through tiny gaps, called synapses, between adjoining dendrites and axon terminals.