This is a brain MRI animation, showing sequential slices of
the brain,
from top to bottom. It was a featured image
at
href="http://en.wikipedia.org/wiki/Image:User-FastFission-brain.gif">Wikipedia.

This was created by a Wikipedia user,
href="http://en.wikipedia.org/wiki/User:Fastfission"
title="User:Fastfission">Fastfission.
The explanation follows:
Made from an href="http://en.wikipedia.org/wiki/fMRI" class="extiw"
title="w:fMRI">fMRI
scan I had done. Goes from the top of my brain straight through to the
bottom. That little dot that appears for a second on the upper-left
hand side is a vitamin E pill they taped to the side of my head to make
sure they didn’t accidentally swap the L-R orientation.