The hurdle with many neural diseases is that we are unable to locate such small damaged tissue in the brain due to the blood-brain barrier and limitations in the current medical imaging technology. The key to curing neural diseases is effective diagnosis techniques to locate damaged cells in the brain. Once we locate the damaged cells, we have ways to repair the neural cells via tissue engineering and drug delivery techniques. In the video below, Jeff Bulte talks about how magnetic nanoparticles can be used to track stem cells in the brain. Stems cells injected won't be seen on MRI since they are too small. However, stem cells magnetized with these nanoparticles could be visualized via MRI. Such works in this field will enable us to visualize damaged cells so that we can repair them via delivering drug molecules, neural growth factors, mRNAs, and etc. Thus some challenging neural/phycological disorders will have a chance to be fixed including autism.