"We are able to measure activities that originate deeper in the brain from the surface without penetrating the brain, " said materials engineer George Malliaras at the Microelectronics Center of Provence in France, who led the research team.

WSJ: Brain Science: Mysterious Neural Circuitry Becomes Viewable

"The thing you need to engineer into the materials is very different behaviour in different directions that the wave travels through it, " he told BBC News.

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Williams met Li, a mining engineer, in 1997 while running a construction materials firm in Tianjin.

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