Moving to Boston soon

Hi everyone!!!

I am a neuroscientist and I am moving to Boston at the end of this summer. I have an exciting offer for a non-paid scientist at an excellent institution in Boston, which within a year might be upgraded (I expect) based on grant applications. But as an unpaid researcher to start with, there is an issue with getting a visa. Does anyone have information or the name of an expert, to help sort this out?

Until last year, I was a senior post doc at U Naples, but in recent months I have not had a formal affiliation (although I continue conducting research there).
Thanks,

Carolina