Programs can have different types of positions - categorical, advanced, or both. Think of neurology residency as 1 year of internal medicine + 3 years of neurology training. That means that PGY-1 year, you'll be a medicine intern. PGY-2, PGY-3, and PGY-4 are your neurology years.
Categorical programs - these are the four year ones you are seeing. This means that when you will apply for a spot, you will not have to apply separately for a PGY-1 position. Essentially your IM year and your neurology training is integrated. No separate interviews for your medicine program needed.
Advanced programs - the three year programs. You are applying for PGY-2 neurology spot. This means that you'll have to interview for a PGY-1 preliminary medicine spot. Even if you're planning to spend 4 years at the institution, you will have to interview separately for neurology and medicine. You can do your preliminary year at a completely different institution if you wish to do so.
Some programs will have a combination. They will have a set number of categorical spots, and will also offer a few advanced spots, and when you apply you can apply to either, or both, depending on what your situation is.
Also, I'm sure many programs are busy with their ranking process for the upcoming match next month, so that may be why institutions have not contacted you.
Hope this helped.