An American scientist convicted of lying to U.S. authorities about payments from China while he was at Harvard University has rebuilt his research lab in Shenzhen to pursue technology the Chinese government has identified as a national priority: embedding electronics into the human brain. Charles Lieber, 67, is among the world’s leading researchers in brain-computer interfaces. The technology has shown promise in treating conditions such as ALS and restoring movement in paralyzed patients. But it also has potential military applications: Scientists at China’s People’s Liberation Army have investigated brain interfaces as a way to engineer super soldiers by boosting mental...