The idea of someone being able to tell exactly what we are thinking is no doubt a scary one, but don’t worry, we’re not there yet. This said, the electroencephalogram, or EEG has been used for some time to measure brain activity in human patients and there is a great deal of information to be obtained from all those wiggly lines.
How does EEG work? Our brains are made up of billions of neurons, communicating with each other all of the time. Brain cells “talk” through synapses, creating tiny electrical signals. With so many cells in the brain, this produces masses of electrical activity and it can be measured by placing sensors on the surface of the skull. This is usually done with the familiar EEG cap, containing a great number of sensors, meaning that different areas of the brain can be measured simultaneously.
What can you see? What we find when we record this brain activity is that the signal within the brain oscillates in wave-like manner. These brain waves may originally seem confusing and random, but analysis has shown that they can be isolated into discrete frequency bands. You can think of the brain like an orchestra, with all the individual instruments creating different sounds that all come together into one complex piece of music.
What does it all mean? These common frequencies may represent differences in brain states. For example, when you are in deep sleep slow oscillations are seen (called delta waves) or during high levels of concentration fast waves (such as beta or gamma oscillations) may occur, signifying intense thought processing. How about some meditation? Well you won’t be doing that without plenty of alpha waves, associated with relaxation and reflection.
How can it be used? EEG can be used in a great number of ways. We can diagnose some conditions such as epilepsy by recognising seizure activity. There is also potential to help suffers of locked in syndrome (a condition where sufferers, while totally conscious, cannot move or communicate). On a lighter note, many people have been working on ways in which we can control objects with our minds. Just imagine, a brain-machine interface would be able to control a robot, unlock a car or turn on a home appliance just through the power of thought. This isn’t so far of, your own portable (and affordable) EEG machines are available to buy, allowing you to play games and even control the plot of a film through changes in your brain waves.