© Spencer Lowell.

Originally shot for a story titled, “The Art & Science of Slicing Up a Human Brain,” which appeared in the June 2010 issue of Discover magazine, this image by Spencer Lowell then ran again in Esquire to illustrate a story titled, “The Brain that Changed Everything.”

Considered to be the world’s most famous brain, it belonged to a man named Henry Molaison, known as “Patient HM,” who had a memory that lasted only a few minutes as a result of brain surgery conducted in 1953 that was intended to stop his severe epilepsy. HM lived for 55 years after his surgery without being able to form a single new memory and in that time was thoroughly studied by the scientific community for his condition.

HM’s brain is important because it allowed scientists to determine the exact part of the brain where memory function originates (the hippocampus) since that is the part of his brain that was removed. Despite this loss, HM was still able to learn things, such as getting better at working through a maze, though he couldn’t remember having done the maze. HM was also able to remember parts of his life from before the surgery, which showed that there all different types of memory (long term, short term, conscious, unconscious) and they are not all localized in the hippocampus. Before HM, memory was a completely abstract concept.

When HM died in December of 2008, his estate agreed to donate his brain to The Brain Observatory at UC San Diego. Since then, HM’s brain has been sliced into 2,401 seventy-micron-thick slices and is currently being scanned at incredibly high resolution. In this image, HM’s brain sits in a plexiglass mold waiting to be embedded in gelatin, frozen, sliced, dyed, mounted, and finally scanned. Lowell believes that the importance of this image beyond presenting the most studied brain in neuroscience is that it’s a visual record of something that no longer exists.

To see more of Lowell’s work visit the gallery featuring the 2011 PDN’s 30 Emerging Photographers.