I have mp4 file with 4 audio channels but when I import it into premiere it displays only one channel

I have mp4 file with 4 audio channels which doesn't have audio in channel one. when I import it into premiere it displays only 1st channel. In project window, I try to find other audio channels on audio channel option(modify--> audio channels) but it doesn't show other channels. how do I active other audio channels and  get its audio back?