May 25 (Reuters) - Elon Musk's Neuralink received U.S. Food and Drug Administration (FDA) clearance for its first-in-human clinical trial, a critical milestone for the brain-implant startup as it faces U.S. probes over its handling of animal experiments. The FDA approval "represents an important first step that will one day allow our technology to help many people," Neuralink said in a tweet on Thursday, without disclosing details of the planned study. It added it is not recruiting for the trial yet and said more details would be available soon.