I've finished my bachelor in Cognitive science and mathematics and I'm looking for research opportunities in the US, starting in a half year. Are there any programs for people in my position? The NIH-IRTA only works for citizens and permanent residents. A year ago I've been on exchange to a top American college, but didn't make acquaintances with any of the PI, as the classes were lead by TA's; can I still use my exchange to find an internship somewhere in the US?
Most of the major US founders limited their funding of junior people to US citizens/permanent residents. these same funding bodies (e.g., NIH, NSF) will happily allow PIs to hire international people on grants. Your best bet is probably to find a PI who is willing to hire you directly off a grant.