Study for what? Despite being desperate, you should really narrow down what you want to do. It really helps your case if you're direct about what you want, and not just being one of the thousands of undergrads who are begging for anything.. even saying neurosci isn't all that specific.
What sort of people have you been emailing and what did your email consist of? (curious)
It's such a generation Y characteristic to think that way anyhow.. you should have spent your year establishing relationships with your profs and TAs. Being a random makes it soooooooooo difficult to even get a volunteer position, never mind volunteer/internship research studies or even paid. On top of that you're searching *after* exams? When the largest number of randoms are begining their search anyways?
Getting stuff is all about networking and knowing people, it's a very poor tactic to do otherwise (there are successes though with that method occasionally). I'm not saying its too late for you, but consider how you spend your time; would it be a better idea to get a regular job and adding to your resume? Regardless of what you end up doing, do something, such as volunteer.
(random advice, not necessarily directed at you)
*shakes head*
