Suna

From Memory Alpha, the free Star Trek reference.

Suna was a psychiatrist on the planet Tilonus IV in 2369 in charge of a disorienting scenario with the purpose of gaining tactical information from Commander Riker. He worked at the Tilonus Institute for Mental Disorders where Riker was subjected to various experiments to gain the information. The plan failed when Riker, sensing a ruse, had himself beamed back to the Enterprise-D in an emergency beam out. (TNG: "Frame of Mind")

Suna was played by Andrew Prine.