Feelings, sensations that you thought was dead
No squealing, remember: that it's all in your head
There's a certain irony to the purpose of the entire song, that a dead person is the one bringing back people's sense of movement and rhythm.
"It's all in your head" is a play on words. People haven't forgotten the beat, it's still there waiting to be unlocked, but Del is also there guiding and controlling you.