Alzheimer's, depression, Parkinson's and the rest of the neuroscience targets of interest in biopharma have created a disaster zone for R&D teams in recent years. That's why AstraZeneca ($AZN), GlaxoSmithKline ($GSK) and others have either pulled way back or completely out of the field. But in their wake, you can now detect a new generation of small biotechs stepping up with promising programs to revolutionize the field. And you need only go so far as today's gene therapy deal between Sanofi ($SNY) and Voyager to get an idea of some of the ideas now coming into play. Forbes' Matthew Herper followed the trail of news crumbs to put together a must-read trend story on the "brain boom." And you can find it here.