I've heard people joke that the Michelangelo's Creation of Adam scene (Sistine Chapel ceiling, 1508-1512) looks like it displays a cut-away section of the human brain (with the oval-shaped cloth depicting the shape of the brain, and all of the heads and bodies suggesting brain matter). You can imagine how surprised I was to learn that scientists are currently arguing that there is a connection with Michelangelo's Sistine Chapel and depictions of the brain, although not with the Creation of Adam scene.
Instead, Ian Suk and Rafael Tamargo argue that the scene Separation of Light from Darkness contains a depiction of a human spinal cord and brain stem. You can read the Scientific American article about these findings here. And take a look at this image:
I think this is an interesting connection, but I do have some doubts. Michelangelo often made his figures extremely muscular and bulky (almost overly-idealized, in my opinion), and this detail of God the Father's neck could just indicate the artist's penchant for muscles and chiaroscuro/modeling. But, like I said, this brain theory is still interesting. I'm not familiar with enough scientific or anatomical imagery to make a definite conclusion on this new argument, but it's fun to consider.