Andrew Huberman· PhD
So there are very safe, well-tolerated gene delivery mechanisms that are called adeno-associated viruses, AAVs, and these are things that are associated with the common cold. They themselves don't cause any symptoms. They've been engineered, and there's been a broad community of viral engineering that's been going on for decades making these safer, well-tolerated, and so on. We can put the channelrhodopsin gene into these viral vectors that deliver the gene and we can have little bits of additional DNA that govern expression only in one kind of cell, but not another. These are called promoters and enhancers, all genetic tricks built up by a very broad community of great scientists over the decades.