Zombie Biology, Pt. 2: Zombie neuroscience
This is the second post in a 5-part series on the biology of zombies. More info and links to other posts here.
When I watched the first episode of The Walking Dead series, based on the comic book series of the same name, I was stunned: “They can show this on TV?!” Apparently we now live in a society where it’s ok to show a horse being disemboweled, with a mere warning of graphic imagery at the beginning of the episode. Some of my friends thought the plot dragged on through the first season a bit, but I loved it.
And one of the show’s most endearing details to me was that the safe haven city (supposedly) was Atlanta, Georgia. Not because I think it’s a great city or anything, but because this choice showed the emphasis the writers put on science: Atlanta was the city worth protecting because it is where the headquarters of the Center of Disease Control (CDC) are located. After all, if anyone is going to cure a zombie outbreak, you’ve gotta protect your scientists!
After surviving countless horrors, Rick and his small posse of survivors finally make it to the CDC, expecting to find a city of scientists working swiftly to find a cure for zombie-ism who would take them in. But when they go inside, they find a single man — the last man standing, working alone towards a cure in the vast complex.
Because no mad scientist is able to hold in his secrets, he quickly gives in and explains to them what he knows of the science behind the zombie outbreak. He asks his computer to call up TS-19: A video of the electrical impulses in the brain of Test Subject 19, a volunteer who allowed the scientists to study her as she succumbed to her zombie bite. As they watch the neuron’s of the still-human brain flicker on the screen before them, Dr. Jenner explains:
Somewhere in all that organic wiring, all those ripples of light, is you — the thing that makes you unique and human… Those are synapses, electric impulses in the brain that carry all the messages. They determine everything a person says, does, or thinks from the moment of birth to the moment of death.
The survivors gaze slack-jawed at the light show before them until the brightness begins to dim, with black roots growing up from the base of the neck into the brain, until everything goes black. “What is that?” they ask. Luckily, they have a SCIENTIST in the room!
It invades the brain like meningitis: the adrenal glands hemorrhage, the brain goes into shutdown, then the major organs — then death. Everything you ever were or ever will be, gone.
But wait, there’s more. After a little while, between 3 minutes and 8 hours, according to Dr. Jenner, the black roots turn to a glowing red, reactivating just the brain stem. (I’ll give the writers the benefit of the doubt and say the scientists recolored the zombie electricity later for effect.)
It basically gets them up and moving… [but] it’s nothing like before… Dark, lifeless, dead. The frontal lobes, the neocortex, the human part — that doesn’t come back. The you part.
While a nice shot, this explanation wasn’t satisfying enough for me. Sure, the brain stem might get em moving, but what makes a zombie want to eat other people? What makes them murderous, and angry?
I’m fortunate that I didn’t have to do this research because it would take far too many hours to get me competent in brain territory. But Dr. Steven Schlozman of Harvard Medical School made a fabulous video going through each aspect of zombie behavior and explaining what parts of the brain must be reactivated for a zombie to really exist! (via bioephemera)
But there is another zombie-related brain question — why do they want to eat human brains? BRAAAAAIIINS?
This never made sense to me. I mean, after a while, when the zombies gather in hordes and there are few living humans around, you would think they would need any energy they can get and not really discriminate by species or favored body part. Of course, not all zombies eat brains — in The Walking Dead they’ll eat anything, animals included, and the entire thing. (So resourceful.)
Perhaps brain-eating rose as a zombie characteristic because if they ate all of their victim, zombie-ism wouldn’t propagate very far. Gotta leave the prey a leg or two so that they can stumble and limp appropriately and, since zombies are altered in behavior, maybe they’re missing part of their brain. Got it.
Perhaps my favorite zombie movie is Return of the Living Dead, featuring punks fighting zombies (with a great soundtrack to boot). According to Wikipedia, this is also the film that debuted the zombies craving brains, with their stereotypical yell: “BRAAAIAIIINNNS!”
While hiding out in a funeral home, the humans manage to capture a decaying zombie torso — which I believe is given a tribute in the first episode of the Walking Dead (see how I did that? full circle!) — and they tie her up and ask her about her habits. “Why do you eat brains?” She told them that it helps her to cope with the pain of being dead. “I can feel myself rotting… [Brain] makes the pain go away.”
It’s unclear how exactly this helps — what is it about brains that would dull the pain of feeling your own body rot? But at least it’s an explanation, and, being as obnoxious as I am, for me any explanation in science fiction is better than none.