Zombies, a Neurobiological Perspective

Brains, all zombies crave them.  Why do zombies desire brains and what do zombies do with them once they’ve got their zombified fingers on them?  I don’t know if we will ever be able to answer this question, well at least not until the impending zombie apocalypse comes.  There are two main theories as to why zombies want brains (although most people assume it is some combination of the two):

1. to eat them
2. to infect them

If you are an unfortunate soul and your brains fall into the hands of zombies there are two commonly accepted fates for you

1. you become zombie food
2. you become a zombie

Again most people assume that in reality it is probably a combination of the two.  I’ve decided that its time I do something useful with my extensive neuroscientific education. Hence the title Zombies, a Neurobiological Perspecive.

A Few Key Assumptions

Before I begin I would like to make three key assumptions, or rather postulate three axioms, without either of which this analysis could not happen

1. Zombies are alive
2. Zombies have a working nervous system
3. Brain regions that controlled X in the pre zombie state still controls X in the zombie state

Why do I make these axioms? Simple.

1. If zombies aren’t alive then what are they? What gives them the ability to move and do all the things that every zombie wants to do.  While I am no expert in necromancy I’m going to assume that zombies are living organism that have cells with metabolic needs, etc, etc…
2. If zombies don’t have a nervous system than I have no idea how they are able to locate brains and then control their muscles to move towards those brains.
3. Assuming the visual system isn’t damaged during the zombie transformation period it would make sense that these same circuits and pathways would be used in whatever visual processing a zombie might do. There might be slight differences; however, like the face area might become the brain area or something of that sort.

Zombie Behavior

Now that I’ve gotten that taken care of, what can we say about the state of the zombie’s nervous system? To answer that question we have to examine what behaviors a zombie can perform.  As I have no zombies to study I’m forced to turn to popular culture zombies to compile a list of basic zombie behaviors.  From the various sources at my disposal I compiled the following list of basic zombie behaviors that are required for the acquisition of brains:

1. Zombies can move, walk, or drag themselves along the ground if need be
2. Zombies can vocalize basic sounds that are mainly restricted to grunting and moaning although the occasional “brains”  has been reported
3. Zombies can see and or hear. Its unclear what they hear and or see and if their vision and hearing is like normal un-infected individuals. Some believe that zombies simply posses “brain vision”. “Bain vision” is similar to x-ray vision but instead of seeing bones they see brains. These individuals also tend to argue that all zombies can hear is the pulsations of your brain as blood is pumped through its tender lobes.
4. Zombies have a limited problem solving ability. They frequently use limbs to prevent door closure and will stand in front of moving cars in an attempt to slow down a fleeing brain.
5. Zombies can become highly aggressive. When agitated they can become quite ferocious
6. Zombies live in communities. This too is a debated issue as it is unclear if the zombie society is left over from the pre-infected society or if zombies tend to congregate post-infection. I tend to think the later is the case, as group hunting tends to be more efficient and bountiful.
7. Zombies can discriminate zombie from non-zombie, this is also further evidence for point 6, but perhaps this is simply the ability to distinguish between human and non-human brains

How Do Zombie Brains Differ from Our Own?

This is a difficult question to answer but there are a few key pathologies that I’ve been able to identify.

First of all it appears that zombies have a damaged Frontal Lobe. This is evident from the fact that zombies cannot control their impulses and as soon as they sense brains they have to go after them.  It doesn’t matter if they are enjoying a good book, mowing the lawn, or playing parcheesi if they are in close proximity to fresh human brains they will immediately get distracted. There is nothing they can do to prevent this. This is clear evidence that they have a damaged or non-existent frontal lobe.

It also appears that zombies have a compromised Vestibular System as they can’t seem to keep their balance.  If you were to ask a zombie to walk a straight line they could probably do it, assuming their were fresh brains waiting for them. However, I feel that if you were to give the zombie a strong shove from the side they would simply fall over. This inability to balance is direct evidence for a damaged vestibular system.  My guess is that the damage is to their semi-circular canals of the cochlea although I can’t be sure without direct examination.

Another brain structure that is most likely damaged in the zombie is the Amygdala. In normal individuals the amygdala controls fear and aggression. As zombies display no fear of fire, grenades, semi-automatic weapons, automatic weapons, and the occasional chainsaw I feel fairly safe in saying that their amygdala is damaged.  Further evidence for a damaged amygdala comes from the heightened aggression zombies display.  Animal studies have shown that animals with damage that causes hyper-active amygdalas can be extremely aggressive.  These two facts are not in opposition as there are two regions of the amygdala each controlling a different behavior.

For the most part though it seems as though zombie brains are actually quite intact and functioning.

What does this all mean?

As I have argued above I feel it is safe to assume that zombies have semi functional brains. This implies that while a few brain regions are damaged during the process of becoming a zombie,  brain for the most part the isn’t that affected. This means that if zombies want to completely eat you brain you are not going to end up as a zombie but simply as a zombie’s snack.  However if the zombies really only want to consume the frontal part of your brain it is conceivable that the the trauma to the skull would damage your cochlea and that after satiating themselves with your frontal lobe they polish off their meal by eating half of your amygdala its conceivable that you too could easily become a zombie.

Anyway this is all very speculative and we won’t have any conclusive evidence until after the zombie apocalypse arrives at which time I will probably be one of many neuroscientists running around trying to collect samples, chainsaw in hand.

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Posted by slayton on January 15, 2010

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