Can't hear audio tracks that are a darker shade.

I am working on a project that has been worked on by several other editors.  All the camera audio has separate tracks for the different mics they had running.  If you look at the screenshot below, only the lighter shaded tracks can be heard.  I can't figure out how to unmute the darker shaded tracks.  If I re-add the files to the timeline, it puts the audio in as three separate tracks and all are the same shade and unmuted.  Any help would be greatly appreciated.  Thank you!