A digital twin is essentially a mathematical model running on a computer. If a person’s digital twin is created at birth, then, with the help of the collected data, it will be possible to predict future diseases, and such a “digital twin” can become the basis for individual treatment. Digital twins - virtual images of real things - have already become the basis of production, industry and the aerospace industry (NiT already wrote about the "digital twin" of the Su-57 engine). There are digital twins of cities, ports and power plants. The term was first introduced in 2010 by NASA researcher John Vickers in a report on the plans of the technology development agency, and according to industry analysts, by 2026 the market for digital twins could reach almost $ 50 billion. This idea soon seeped into biology. In 2016, Bill Rach, then the chief executive of GE Digital, predicted that “we will have a digital twin at birth that will collect data from sensors and use this information to predict various diseases, cancer and other things.” The digital twin can become the basis for individual patient treatment and predict how their disease may develop. It can even be used to test potential treatments instead of risky patient trials. While these projects are mostly in the early stages. A research program called Echoes, which involves scientists from Europe, the UK and the US, is working to create a digital heart. Siemens Healthineers, a German medical device company, is aiming to do the same. Dassault Systèmes, a French software company, has teamed up with the US Food and Drug Administration (FDA) to approve what it calls "The Living Heart." The Austrian company Golem creates digital twins of at-risk people living alone. The idea is that the digital twin constantly monitors their health, alerting carers if they get sick and need help. Now researchers are aiming for the ultimate goal: creating a brain twin. As part of the Neurotwin project, it is planned to create a computer model of the entire brain of a particular patient. The Neurotwin team hopes the model can be used to predict the effect of stimulation in the treatment of neurological diseases, including epilepsy and Alzheimer's disease. They are planning a clinical trial starting next year that will create digital twins of about 60 Alzheimer's patients who will be treated with stimulation optimized specifically for their brains. A second clinical trial scheduled for 2023 will be carried out in the same way, but for patients with treatment-resistant focal epilepsy. The purpose of these trials is to test the concept and determine if the approach works and can improve outcomes for these patients. If successful, the team plans to expand the application of its technology to other aspects of the brain, such as those involved in multiple sclerosis, stroke rehabilitation, depression and psychedelic exposure. Approximately one third of patients with epilepsy do not respond to medications. Non-invasive stimulation, in which electrical currents are delivered painlessly to the brain, has been shown to help reduce the frequency and intensity of seizures. But this technology is still quite new and needs to be improved. This is where a virtual brain can come in handy. To create a digital twin of a patient with epilepsy, the Neurotwin team takes half an hour of MRI data and 10 minutes of EEG (electroencephalography) readings and uses them to create a computer model that captures the electrical activity of the brain, as well as to realistically simulate the main brain tissues, including the scalp, skull , cerebrospinal fluid, gray and white matter. The doppelgänger will include a network of built-in "neural mass models". Essentially, computer models for calculating the average behavior of many neurons connected to each other using a patient's "connectome" - a map of neuronal connections in the brain. In the case of epilepsy, some areas of the connectome may become overexcited; in the case of, say, a stroke, the connectome may be altered. Once the doppelgänger is created, the team can use it to optimize stimulation of the real patient's brain. For example, for more effective treatment of a patient suffering from epilepsy, he is put on a headdress for 20 minutes daily, which provides transcranial electrical stimulation of the brain. Using a digital copy, Ruffini and his team can optimize the position of the stimulus electrodes as well as the level of current delivered. The digital twin of any organ raises a number of ethical questions. For example, does the patient have the right to know or not to know if, say, his doppelgänger predictsthat in two weeks he will have a heart attack? What happens to the twin after the death of the patient? Will he have his own legal or ethical rights? On the one hand, virtual body twins open up exciting, revolutionary avenues for developing new therapies, says Matthias Braun, an ethicist at the University of Erlangen-Nuremberg in Germany, who has written about the ethical implications of digital twins in healthcare. "But on the other hand, it poses challenges for us," he continues. For example, who should own the digital twin? The company that creates it? "Or do you have the right to say, 'I oppose the use of specific information or specific projections regarding my health insurance or use in other contexts'? In order for this not to be an infringement on autonomy or privacy, it is important that the individual person controls the use of [their digital twin],” he says. The loss of such control will lead to what Brown calls "digital slavery." Ana Mykes, CEO of Neuroelectrics, says the company has already grappled with the question of what will happen to the highly personal data on which the digital twin is built. "When you do personalizations like this, you have to ask tough questions, right? Who will own the data? What are you going to do with the data?" she asks. To analyze the ethical and philosophical components of the project, researchers were involved, including Manuel Guerrero, a neuroethicist from the University of Uppsala, Sweden. For the Neurotwin project based in Europe, the collected data will be protected by the European Union General Data Protection Regulation (GDPR). This means that any use of the data requires the consent of its owner, says Guerrero. Guerrero and his team are also exploring whether the term "digital twin", which was first coined for production, is the most appropriate term for replicating something as complex and dynamic as a living brain or heart. Could its use lead to misunderstandings or high expectations in society? "The brain is much more complex than other types of doppelgangers that are created through manufacturing, so the notion of a doppelgänger for the brain is something that is a matter of debate in the neuroscience community," he says. Working with the brain is many orders of magnitude more complex than modeling the heart or kidneys, and it's also potentially more ethically complex. "We're building quite sophisticated computational models of the brain," says Ruffini. "At some point, I think it will become unclear whether this digital twin is a digital copy or a sentient being." Brown believes the time has come to reflect on these difficult questions. "I think these are really important issues that we need to address now," he says. "We know what happens when you just say, 'Well, just develop the technology and then we'll see,'" he adds, warning of the dangers of postponing ethical and moral consequences to a later date. But the Neurotwin team argues that Done right, creating digital twins can not only greatly improve patient outcomes, but also increase our knowledge of intractable brain diseases.“We are working to really help people suffering from brain diseases from a completely different perspective,” says Mikes: "We like to call this a new category of therapeutics where you really use the power of physics and mathematics to decipher the brain."