How to scale down objects without scaling down where they are in relation to each other

I am editing an illustrator file someone else made in which there are a series of 500+ circles/dots that are organized in the shape of an organ. The circles are very big, though, and I want to scale the size of the circles down, without scaling the size of the organ down. The circles are all different sizes though. Is there a way to do this without going to each individual circle and editing it? 

Thanks in advance for any help anyone can provide!