Working with other labs, aside from your own PI's as a Graduate student?

[HYHY02]

I'm just wondering if this is possible/how it's done.

 

In the new lab I'm in (Masters 1), and from talking/hearing the other higher level graduate students in my lab, it seems as though many spend time with other lab members in other labs in the university to kind of learn certain topics, or even with the PI's from other labs. For example, my research is grounded in neuroimaging, and with this, certain labs are better at certain techniques than others. From the sounds of it, it's not uncommon for students who are learning specific techniques to go and work with the lab members/PI of a lab that is proficient in that technique.

 

I just wanted to know if others have heard about this type of thing in general through Grad school, and if I wanted to kind lurk around another lab, would I go through my own PI first, or would I directly contact the PI of the lab I would want to spend some time in?