I need a realistic brain. Anyone have any ideas?

City Morgue. Worked for Da Vinci.
Or, if you're into not getting arrested, you might be able to make one out of clay if your budget is tight and you have a sculptor who could do that for you. Or maybe you could get one from a science supply place, the sort of place that sells models to science classes.

Go to your local supermarket, buy a cow brain. Should be cheap, too.
It doesn't get much more realistic than that.

E.

This is a lot easier in smaller towns, but try to find a small family run grocery store (that butchers and cuts their own steaks) and ask for a brain. You can probably get one for free. I got a few cow eyes and a heart for absolutely no cost.