iPod recognizes iTunes, but iTunes doesn't recognize iPod

This is to say that according to my iPod Classic, it is connected to iTunes. iTunes, however, doesn't acknowledge that anything is connected to it.

There's no error message, no unknown message, anything like that. There's just no acknowledgement from iTunes that anything exists at all. (Note the photo below, where you can see the cable icon and the "Connected" message on the iPod, but no little iPod icon or any other acknowledgement on iTunes.)

I have tried restarting the computer, restarting iTunes, restarting the iPod, and tried every UBS port on the computer, including ones that are still currently working for both my external HD and my iPhone. iTunes recognizes both. It does not know that the iPod is there. Please, someone, tell me what else to do.