brain imaging bipolar

What material should I use for a model of a human head?
Therefore, I have a new project for Biology class of genetic diseases, mine being bipolar mania. What I wanted to do is to model a human head with half a brain exposed to show that maybe he said that the problem not him. See this image for what I'm saying sorry http://i53.photobucket.com/albums/ drawing g68/Eyes-kun1819/head.jpg wrong. Anyway, what you suggest I use for this? Thanks in advance!
depending on how big it has to be you could use as clay or PhimoDough () spelling? Yes … really depends on how big it has to be good luck … sounds fun
On MLK Day: I, Too, Have a Dream By Therese J. Borchard