This brain was modeled by Aleksey. Check out his work here: https://kashpersky.com/brain. I imported the Alembic file into Houdini and used a slightly more complex VEX grouping to connect random points to make the vessels.
We've been doing a lot of Migraine MOD / MOA visualization and I had a model of a brain to play with. In my spare time I have been playing with Houdini's VEX language and poking around NASA's Public Domain Library.