Can we really travel with the power of thought?

Communication by Thought - Progress or Nightmare?

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For some, this research is a blessing. Completely paralyzed people are able to communicate with their relatives and carers thanks to innovative brain-machine interfaces. In Kyoto, brain researcher Shin Ishii is building a model house whose residents will be able to control their household appliances remotely with the help of brain waves. Game makers are marketing neurofeedback games as the next big thing.

For others, the visions of neurotechnology are a nightmare. Dave Eggers ’novel The Circle describes a hyper-transparent society in which every movement, every friendship, every word is made public by the Apple-Google-Facebook-like super company The Circle. In the last scene, one of the protagonists is in a coma in the intensive care unit. A monitor shows their brain waves, but nobody understands the signals. It is the last data that the group cannot yet decipher. A scandal! The Circle has to change that.

How much one would like to look into the heads of others every now and then. Know what they are really thinking, whether they are hiding something or lying, whether they are reciprocating our feelings for who they really are. In the film Strange days Kathryn Bigelow can even record a person's experiences via a brain-computer interface and transfer them to other brains. The streams of consciousness are traded on the black market like a kind of soul porn: You penetrate the world of strangers during sex, feel the adrenaline rush of a gangster, watch the world through the eyes of a dying person. Back in the nineties when the film was made it was sci-fi. If you follow the news from brain research today, you will find yourself wondering when the app will be added.

Mind reading is becoming a serious science. But with every new sensational report, you have to look carefully to see what the experiments have really shown. Does someone simply read out two motor signals to send binary characters around the world? Does the method only work if the skull is opened beforehand? Did the research hero first have to train for hours in the brain scanner?

One of the mind readers' headquarters is located near Berlin's main train station, on the premises of the Charité University Hospital, although the researchers would of course never call themselves that. This is where John-Dylan Haynes peers into the brains of volunteers with the help of large magnetic tubes; this is where the new possibilities, but also the major hurdles of neurotechnology, become apparent. Functional magnetic resonance imaging (fMRI) is Haynes ’favorite method, also known as a brain scan. This enables the researchers to determine in various experiments whether a test person is thinking of a dog or a cat, whether they would like to buy a certain product or not, whether a subject would rather add or subtract given numbers, whether someone would like to buy a place has seen before. "When I think certain things, it is reflected in certain brain processes," says Haynes. "There is content of consciousness, and there are brain processes, and they obviously have something to do with each other systematically." One is mind, the other is brain. With the help of mathematical procedures one tries to link them.

The philosopher Ludwig Wittgenstein was convinced that man could only think in words. "The limits of my language mean the limits of my world," he wrote a hundred years ago. John-Dylan Haynes is a pragmatic scientist, he prefers a different definition. Thoughts are "all things that we consciously experience," he says. "These can be the simplest of sensations, feelings or images, memories and even complex sentence-like structures."

A brain scanner initially only measures changes in blood flow in the brain. The principle is that where there is more blood flowing, the brain consumes more energy, and this is where the nerve cells - the neurons - are particularly active. The images show the activity in volume elements the size of a grain of rice - doctors speak of voxels. "These images are often misunderstood," says Haynes. "They are not photographs of the brain, they do not show where thoughts are, they just show where something is happening." Only with the help of learning algorithms can meaningful interpretations be derived from the activity patterns of individual brains. Just as a fingerprint belongs to a very specific person, every thought also has a specific activity pattern in the brain. However: every brain thinks differently.

Thoughts are colored biographically and accordingly coded differently. "When I think of a dog, something different happens in my brain than yours," says Haynes. A dog - for some, this is a fluffy companion and a loyal friend from childhood. Others, on the other hand, think of loud barking or the memory of a painful bite. There is no universal thought pattern for the dog. And not for a bike or them either Mona Lisa. That is why the computer must always first learn which activity pattern is used to encode a certain thought in the brain of an individual person. The subjects in Haynes’s magnetic resonance tomographs think, as it were, on a trial basis. The researchers create a database for each of them. With a pattern comparison, you can later reconstruct what someone is thinking about.