Mine are doing the exact same thing, but because it's a very new patch (I only planted the raspberries last year!) I'm going to leave everything the way it is for this year and most of next and see what happens.
I was told that raspberries produce fruit on their 2nd year canes, so if you plant a raspberry this year, it will grow canes and so on, but it will produce fruit on those canes *next* year so you want to leave them alone until after they bear. You get rid of them after they bear, to make room for the new growth.
My little volunteers are all Heritage, which is good, because the main cane has died, I think, and so if I want Heritage raspberries, this mass of volunteer canes is what's going to give them to me!
I only have one 2nd year cane this year thanks to rabbits, so I am jealously eyeing that one, and figuring that I'll have to start from scratch and leave it alone (again) for one more year, in order to get back on track.
I may get a handful of berries from this single cane, but all the new growth on it suggests that next year's crop will be much better, and from then on, we'll be where we're supposed to be.
stupid rabbits!
Anyhow, in answer to the OP, frankly (as another MN gardener) I'd just leave them be for right now. Let them grow, and see what happens. You can always get rid of them next spring.
Whitewater