Electrical Brain

WANDERING IN THE DARK

People have always been intrigued by what is happening in the minds of others. However, not many may realise that there is huge potential that can be exploited to improve our performance or quality of life if we learn how to interpret brain activity through technology.

But first let’s look at the history of mind studies.

While Hippocrates (400 BC) believed the brain to be the seat of intelligence, some 50 years later Aristotle claimed that intelligence was actually located in the heart, the brain being only a cooling mechanism for the blood. Aristotle based this notion on the observation that the brain has a very good blood supply. He reasoned that humans are more rational than beasts because they have a larger ‘cooler’ to keep their hotbloodedness and animal instincts in check. Our knowledge of the brain improved throughout the centuries, but neuroscience saw a real breakthrough only in the 19th century, when the first neuroscientists tried to figure out whether the brain is divided into specialised regions or whether it functions as a whole. By performing meticulously designed tests, they realised that the truth lies somewhere in between – while the brain can be divided into specific functional areas, certain functions are spread widely across several areas.

In the recorded history, the brain was first mentioned by ancient Egyptians, who described the symptoms of soldiers with a broken skull. The image shows the hieroglyphics for the word brain, which was first found in Edwin Smith’s Surgical Papyrus.

One of the earliest anatomical drawings of the lower brain by Andreas Vesalius from 1543. Until then, these were very inaccurate, because the dissection of bodies was punishable by death practically throughout history. Knowledge-thirsty Greek and Roman doctors therefore based most of their anatomical knowledge on the dissection of monkeys, which lead to unfortunate errors when applied to humans.

BRAINWAVES

Neuroscience truly boomed in the 20th century. Progress in noninvasive imaging technology and the measurement of weak electric and magnetic fields produced by the brain revolutionised our understanding of how the brain works.

In 1924, German neurologist and psychiatrist Hans Berger was the first one to measure the electrical activity of the human brain. He did this by placing two thin silver electrodes onto the subjects’ scalps, one to the front and one to the back of the head. Between them he connected a galvanometer that was extremely precise for that time, and detected a small, changing electrical current between the electrodes. He also found that the signal changes in a predictable way. For example, when the subject’s eyes were closed the frequency slowed down to about 10 Hz, and he called this Alpha waves. Today, we associate alpha waves with tiredness and sleepiness. This is how the electroencephalogram (EEG), a special device that tracks and records brain wave patterns, was born.

A visual representation of delta, alpha, beta and gamma EEG waves.

I THINK, THEREFORE... I ACT?

Soon after Bergman discovered EEG, researchers started using it to find out more about the living brain – something that was unthinkable until then. One of the best known neuroscientific experiments was done using the EEG – this simple discovery agitated representatives of some religions, provoked criticism by philosophers, and captured the attention of researchers.

In 1962, a team of German neurologists performed a test where the subjects were asked to move their finger repeatedly. The scientists found that the electric activity above the motor cortex of the subjects increased before they moved the finger. What made this unusual was that the signal started more than a second before the muscle moved, which meant that the signal plays a role not only in the muscle movement, but also in our preparing for this movement. In recognition of this fact, the signal was named readiness potential (German: Bereitschaftspotenzial – BP).

A surprising addition to the above was made in 1982, when American scientist Benjamin Libet changed this experiment and revolutionised our perception of free will. The subjects in his experiment watched a clock hand moving in circle. They were asked to move their finger whenever they felt like it, and then report the exact position of the clock hand at the moment they felt the conscious ‘will’ to move. The results showed that free will emerged only about half a second after the BP occurs, meaning that your sense of free will comes half a second after the electrical activity of your brain already ‘knows’ you are going to perform the movement. As disconcerting as this may sound, we cannot deny the widely accepted interpretation of this seminal experiment, which says that conscious free will is most likely only an illusion created by our brain – at least when it comes to moving our fingers.

A MOBILE EEG FOR EVERYDAY USE

Libet’s experiment on free will is a great example of the versatility of the EEG. Its use is not limited only to clinical practice; it can also be used as a tool for discovering various aspects of the human mind. However, the main challenge of applied neuroscience is translating knowledge. While research labs happily churn out data on how the aver-