The brain is _unusually_ protected though. There's nothing like the blood brain barrier basically anywhere else. Most the the tissues you mentioned are exposed

The brain is _unusually_ protected though. There's nothing like the blood brain barrier basically anywhere else. Most the the tissues you mentioned are exposed to the environment in some way. There aren't many ways to reach the brain without getting inside the body first(sensory organs being the obvious pathway, but even that is a stretch). Not saying it's impossible, just that the skepticism is warranted.