This brain was a real quick creation for a project I did. It is in no way anatomically correct, but it might suit some people's needs.
MacBinary (preferred) <2.9Mb>
BinHex (for PCs) <3.9Mb>
The file can be expanded with Stuffit Expander, and will expand to 11.9 Mb.
You will need a healthy amount of RAM to work with this model, as it has a lot of polygons.
Check your 3D app with the scene you want to use it in and see if you have enough memory free for an additional 11.9 DXF file before downloading.