China has launched a plan to develop the world’s most powerful brain scanner, one that could generate an extremely strong magnetic field to observe for the first time the structure and activities of every neuron in a living human brain.
The goal is to build the world’s most powerful magnetic resonance imaging device.
The projected scanner would not only produce a snapshot with details far beyond what existing instruments can provide, but also track various types of chemical agents including sodium, phosphorus and potassium that pass critical signals along neural fibre networks to study consciousness and brain-related diseases such as Parkinson’s.
The billion-yuan device “will revolutionise brain studies”, said a senior scientist working on the project, which is based in the city of Shenzhen in southern China’s Guangdong province.
The total budget for the facility, which is still under construction, will exceed that of FAST (Five Hundred Meter Aperture Spherical Telescope), the world’s largest telescope in Pingtan, Guizhou province, said the scientist, who spoke on condition of anonymity because the programme has not gone fully public.
But instead of aiming at the sky, this powerful “telescope” would peer inward to probe the origin and evolution of consciousness, the scientist said.
“It will show us a different world with phenomenon unseen before … maybe even the soul,” he said.
The soul – or human consciousness – remains the stuff of heated debate, the researcher said. From religious leaders to philosophers to ordinary individuals, many people believe it exists and have theories to describe or explain it. But the scientific community has not found any physical evidence to support these claims.
The Shenzhen Institutes of Advanced Technology, under the Chinese Academy of Sciences, released a statement late last month announcing that the first phase of the project had recently been approved by the central government.
The prominent physicist Zhao Zhongxian, winner of China’s top science award for his contributions in superconducting material science, is the programme’s science adviser, the statement said.
Zhao said that China had a solid foundation and advantages in numerous areas like superconducting materials, imaging electronics and engineering equipment. He urged the project team to beat competitors in other countries and said that the only way to do so was by “independent innovation”.
Human tissues such as organs, muscles and brain contain a large amount of water. In a strong magnetic field, the nuclei of hydrogen in water molecules, for instance, align and spin in the same direction.
By applying radio waves to the magnetic field, scientists can make the nuclei flip their spins in opposite directions. By then gradually reducing the strength of the magnetic field, the nuclei would return to their normal state one after another, releasing a weak radio signal radiation.
Detecting and measuring the signal can reveal the internal structure of tissues, direction and speed of blood flows or the intensity of oxygen consumption. In brain science, researchers can use the information to deduce, for example, which areas of the brain are turned on or switched off when engaging in certain types of cognitive tasks.
The technology, known as magnetic resonance imaging, can also help study or diagnose neurodegenerative conditions including Parkinson’s disease and Alzheimer’s.
Generally, hospital MRI scanners generate between 1.5 and three tesla – the unit of magnetic strength named after the Serbian-American physicist Nikola Tesla – although more powerful machines generating up to 11 tesla have been built in the US and Europe. The new Chinese device could generate up to 14 tesla.
While existing MRI scanners can only resonate hydrogen nuclei, at 14 tesla, the magnetic field would be strong enough to excite the nuclei of other, heavier elements.
Molecules containing sodium, phosphorus and potassium, for instance, play important roles in the transmission of electrochemical signals from one neuron to another.
“If we can make these elements resonate in the same manner of the hydrogen, the information we obtain will increase like ‘boom, boom, boom’,” said a Beijing-based physicist also involved in the project.
“We may for the first time capture a full picture of human consciousness or even the essence of life itself. Then we can define them and explain how they work in precise physical terms – just like Newton and Einstein defined and explained the universe,” he said.
The cell body of a neuron has a diameter of four to 100 micrometres. The most powerful MRI machines today cannot see objects smaller than 1mm (1,000 micrometres) in diameter, but the resolution of the new device in Shenzhen will be up to one micrometre, the researcher said.
Scientists involved in the project are excited not only because of the new potential discoveries that could be made by the device, but also for the technical challenge ahead.
Earlier this year, researchers at the University of Minnesota in the US took the first picture of a human body with a 10 tesla machine, with the university saying only that the device “promises to produce scans at a finer level of detail”. Images of the scan were not made available.
The construction of an 11 tesla device was also recently finished in France, but it could still only resonate hydrogen nuclei – not generate stronger fields – because the superconducting material used was the same as in standard hospital machines.
Superconductivity lets electric current run through a coil without resistance. Without it, the coil that generates the magnetic field could melt. The usual superconducting material is a compound of niobium and titanium, a soft material that can be easily rolled around the coil, but which starts losing superconductivity beyond 10 tesla.
Another compound, consisting of niobium and tin, can maintain superconductivity in a high magnetic field, and has been used in large-particle colliders and experimental fusion reactors.
However, the compound also has some shortcomings. The magnetic field it generates, for instance, is uneven. The strength could be higher in one location and lower in another. In large, powerful machines such as a large-particle collider, the error could be tolerated, but for an MRI device it could ruin the entire picture of the brain being scanned.
This material is also fragile, unable to withstand the pulling force the magnetic field can generate, the equivalent of 100 tonnes on a one-metre-long coil.
“To meet the project requirements we need to develop some new superconducting materials,” said a materials scientist involved in the project.
“As far as we know, other countries might have some ideas, but China is the only country taking action to bring the idea to life, thanks to the increasing support to fundamental research by the government,” he said.
The project team said that safety was a priority. No human would enter the device until extensive tests on animals like monkeys had been conducted to prove that the experiment would do no harm to health, the researchers said.
It is expected that developing the technology and coming up with a design will take five years before the construction could start. Because of the technical challenges, the scientists said, there may well be an escalating budget and additional delays.
For instance, the 11-tesla project in France cost 200 million euros (US$228 million) and 10 years to build, and still has yet to release an image.
Professor Lu Haidong, a brain scientist at the State Key Laboratory of Cognitive Neuroscience at Beijing Normal University, said that MRI technology generally had an important advantage over other imaging methods like X-rays.
MRIs did not emit a radioactive beam, so did not harm the tissue, he said.
Studies by health authorities such as the US Food and Drug Administration have found no evidence of lasting side effects on patients who have had MRI scans.
But the strength of magnetic fields in medical practice has only been one-tenth of the power of the planned device.
“No human beings has been exposed to a magnetic field as strong as 14 tesla,” Lu said.
“Some side effects such as internal heating may occur. The safety risk must receive stringent evaluation before scanning a living human,” he said.
Wu Shengjun, a professor of quantum physics in Nanjing University in east China’s Jiangsu province, said he also had concerns about the possible effects on health.
“It is just a hunch, there is no evidence suggesting the device will be unsafe, but I will definitely not go in there,” he said.
Professor He Rongqiao, a researcher at the Institute of Biophysics under the Chinese Academy of Sciences in Beijing who studies the health effects of magnetic forces on the brain, said he did not believe the machine would see the soul or consciousness.
“What is consciousness? There is not even a scientific definition. If you can’t even define it, how do you know what you see is what you are looking for?” he said.
The machine should be safe for humans, according to the theory of physics, he said, but in real life “accidents happen”.
A power blackout, for instance, could put the patient at high risk.
“The strength of the magnetic field must decrease gradually. If it disappears suddenly, the breaking of alignment can be violent and cause damage,” He said.
“It will be like falling off the roof of a tall building.”