Neuroscience: how much biology needed?

Has anyone here had any experience in a neuroscience PhD program? I have a psychology background, along with a bit of biology and physiology, but only a few classes, and I don’t have a minor in biology or anything.

I would like to know if anyone went through a neuroscience program, and if you had lacked a strong biology background, would it hinder you in the long run? Some of the programs I am looking into are separate departments, whereas some universities have psychology area emphases in neuroscience. Some of the websites seem to suggest that the program is interdisciplinary, and that students from many backgrounds are encouraged to apply.