Visiting research scholar vs trainee ?

Recently saw a few people on linkedin stating that they are visiting research scholars at so and so university/ hospital. Looks like they just started after rotations. So does that mean they are still on B1/B2 visa ? What's the difference between Visiting research scholar and research trainee/research assitant/ research coordinator ? ( Mainly interms of visa B1/B2 or J1 research visa) Is visting research scholar a job or just like an elective but for longer time in a research department ? If it's like an elective/short term -can we just be a visiting research scholar on B1/b2 visa ?

Tried connecting with those ppl on linekdin, but no luck. Someone plz clarify this.