Australia-based startup Synchron planted its fifth brain-computer device and the first into the brain of a U.S. patient, emerging as a potential rival to Tesla Inc’s CEO Elon Musk’s Neuralink, which is yet to receive a regulatory nod. What Happened Doctors at the Mount Sinai West medical center in New York, on July 6, implanted Synchron’s first 1.5-inch device into the brain of…