I want to preface this article by saying that I’m going to be talking about some medical stuff, but I am not a doctor. I never finished my residency. Also, I never started my residency or went to medical school. Or college. This was just a topic that I got to thinking about when I was asked a question by Sunshine Somerville, author of the Kota series. I won’t tell you what the question was, because I don’t know if it pertains to something that she is working on at the moment. I’ll just say it got my wheels spinning in a direction that lead me to this article.
We all know that when the zombies get here we will have to destroy their brains to kill them. Not knowing much about the human brain, I had to wonder what that means, exactly. I know the old shotgun blast to the head at close range will do the trick, but what about some of the other things we’ve seen in movies and on television or read about in books? Will a knife through the eye or to the side of the head get the job done? How about blunt force trauma? If you know the story of Phineas Gage, you may have your doubts.
Phineas Gage was a railroad construction foreman. In 1848, a freak accident sent a tamping spike upwards through the left side of his face. It penetrated his left frontal lobe, destroying most of it, and exited through the top of his head. Not only did this not kill Gage, but he lived a full life for twelve years after the accident. If this sort of injury didn’t kill a living person, why would it kill a reanimated person that relies on much less of the brain to function?
The skull of Phineas Gage and the rod that passed through it on display at The Warren Anatomical Museum at Harvard University.
Chances are, a zombie will have little need for its frontal lobe, as it is responsible more for the things that make us distinctly human and not a big part of motor skill or function. The now outlawed psychosurgery known as lobotomy was the practice of severing some or all of the nerve tracts to the prefrontal cortex in the anterior part of the frontal lobe. In the more extreme lobotomies, where most of the tracts were cut or scraped away, the patients could still perform most basic functions, but little remained of their personalities or memory.
So how much of the brain will the zombies be using? Obviously, there have not yet been any subjects to test, so we can only speculate. Researching what most of the brain does, I would guess it will be very little. In fact, I’d say it would be just the brainstem, and only part of it at that, and possibly the cerebellum. The brainstem is located underneath the rest of the brain toward the back, not directly between the ears, but close. It connects the brain to the spinal cord. In many lower forms of life, lizards for example, the entire brain is similar to just the brainstem of a human. Putting two and two together, a person having use of their brainstem without the rest of the brain would be more of an animal than a human being.
There are three major pars to the brainstem, one of which would be completely useless to zombies as we know them. The pons is the part that controls most motor functions, but not enough for those functions to be coordinated, which is the responsibility of the cerebellum, located behind the brain stem. If just the pons were active, we could get up and move around, but we’d walk pretty funny. This is why I feel the cerebellum must also be working for a zombie to fully reanimate and be any sort of a threat. Without the cerebellum, which makes up only ten percent of the brain’s mass but accounts for half of the brain’s neurons, a zombie would barely be able to walk upright. Certainly, any of the newer manifestations of the undead that move quickly and deftly have at least partial use of their cerebellums.
The midbrain also helps control body movement, but not as much as the cerebellum. If zombies are slow, clumsy, and uncoordinated, they more than likely only have use of the midbrain and not the cerebellum. Also, the midbrain controls our visual and auditory systems.
The last part of the brainstem is the medulla, which controls many of the autonomic functions that make our bodies work like breathing, heart rate, and blood pressure. The medulla also makes us vomit when it decides we need some purging. This is the part of the brainstem that I can’t see a zombie having any use of. Unfortunately, my first book contained a scene which features a vomiting zombie, so I’m discrediting myself here. Oops.
So here comes the important part. If, when the dead rise, only the brainstems are reactivated, it may not be enough to just shoot or stab them in the head. I also don’t think that hitting them in the head will work, either, unless it is an intense blow to the back of the head. Think about TS-19, the final episode of season one of The Walking Dead. Dr. Edwin Jenner plays the recording of an M.R.I. showing a person, test subject 19, dying and then turning into a zombie. Upon reanimation, only the brainstem fires back up. Shortly afterward, test subject 19 is shot and killed. Do you remember the trajectory of the bullet? The muzzle of the gun was placed against the forehead, just above the eyes, at an extreme downward angle so that the bullet would hit the brainstem. There are very few other kills on the show that replicate this one, although it is the most accurate in my opinion. A straight shot to the forehead, or one with an upward trajectory, may very well not work.
Throughout zombie history, there are many kills that would not destroy the brainstem and thus not actually result in a dead zombie. It isn’t my intention to nitpick minute technical details of movies, books, and TV shows. If it were, I would ask how someone managed to use a gun inside of an M.R.I. machine. These things are fiction made for entertainment purposes, so let’s be entertained by them and not get uppity about that sort of stuff. My concern is with my safety, and yours as well, during a real zombie apocalypse. Know that destroying the brain is a misleading notion. In all likelihood, you will need to destroy the brainstem, which is a little more of a challenge. Using a gun from a distance, it would be a difficult shot for anyone who isn’t an accomplished marksman or very lucky. The tearing effect of a mushrooming or fragmenting bullet might get the job done, but when faced with the undead, might isn’t good enough for me. Also, when using a knife, it will be better to penetrate the skull through the ear or the back of the head just above the spinal cord. If going through the eye socket, you’ll want to stab with a slight downward trajectory using a knife with a blade that is at least four inches (about ten centimeters) in length.
Again, I am not a doctor or scientist. Everything I’ve written here is purely speculative. By the time any of this can be verified or disproved it may be too late for too many. In matters of survival, one can never be too careful. When confronted by the undead, wasting your effort with ineffective head shots that destroy the cerebral cortex or temporal lobe but leave the brainstem intact could result in your horribly painful death. Make every shot count and, hopefully, you will survive.