I'm really skeptical of claims like « the "thinking unit" is really the whole body », they tend to discard quantitative considerations for purely qualitative ones.
Yes, the brain is influenced, and influences, the whole body. But that doesn't mean the whole body has the same importance in the thinking. The brain is also influenced by lots of external factors (such as ambient light or sounds, ...) if as soon as there is a "connection" between two parts you say "it's the whole system that does the processing", you'll just end up considering the solar system as a whole, or even the entire event horizon sphere.
There is countless evidence that, while your body and your environment have significant influence on your thinking, it's just influence, not fundamentally being part of the cognition. For example, people who have graft or amputations rarely change personality, memory or cognitive abilities in any way comparable to what brain damage can do.
Kipnis et al found a new part of the lymphatic system. It goes into the brain.
The fact that we still get surprised by new elements of the brain suggests that there quite a lot we still don't know about the brain and uploading might be harder than previously believed.
Given that these vessels were hard to find, it will be interesting to see whether other hard to find vessels will be discovered in the coming years.
Besides their Nature article Structural and functional features of central nervous system lymphatic vessels, there a good article on NeuroscientistNews titled Missing link found between brain, immune system -- with major disease implications.