Neuro-/psycholinguistics

Hi, it's my first time posting here.
I'm studying in the English department and am about to start writing my senior thesis. I'm considering writing on language acquisition in autism, because it's interesting to me and I'm thinking about applying for a graduate program in neuro- or psycholinguistics. But the problem is I really don't know how to start and what to write about. Do I have to present a new idea in a bachelor thesis? Or do I just compare and contrast other peoples research results? Any suggestion is appreciated. Please help.