Dr. Hafdahl: “Think of living things like a car on the highway. In addition to the vehicle (the body), it needs two things to work: a driver (the brain) and a fuel source (food). Zombies would be no different! From the brain perspective, I think Romero did a very good job. In order for it to make sense I think the term ‘undead’ is the most proper term to use as we need to think of zombies partially living. Death is loss of integrated function of various organ systems, so brain death is when we lose that integrated function: the control center (i.e., the brain) can no longer control the body. Thus, if zombies are completely dead, the brain, by definition, could exert no control over the body in any capacity. Zombies would have no volitional movement so they would just lie there, which, of course, would not make for a scary movie. ‘Undead’ implies that death occurred, but there is some partial return to life, and the brain is able to regain control (at least partially) over the body again. I can imagine that a zombie, which has returned to partial living and has a partially functioning brain, probably has portions of its brain that still work but also parts that are very damaged. In humans, we can see what happens when small portions of the brain die, such as with strokes, multiple sclerosis, and other neurodegenerative diseases. One of the most interesting parts of brain physiology is that everything you do is controlled by a certain part of the brain. If the speech area of the brain dies, people lose the ability to talk and understand language. If the frontal lobe is damaged, people lose the ability to control their impulses, etc. I imagine a zombie has sustained profound damage to much of its brain, which would explain its loss of speech, impulse control, ability to feel pain, balance, etc. which I think Romero has perfectly captured with these stumbling, aphasic, primitive creatures in human bodies. I’m not sure why motor function is so much better preserved than other parts of the brain, but I guess that they have to move to be threatening!”
The brain.
Meg:“Do you think that’s why Romero chose to kill the zombies with a shot to the head? Because, supposedly, there is one part of the brain still functioning?”
Dr. Hafdahl: “I would suspect so! It seems to make sense that you kill the undead by severing the ‘control’ to make them dead again.”
Meg:“Or deader! Is that a word? More dead?”
Dr. Hafdahl: “Ha, yeah, exactly! So, going back to the car analogy, the other thing that zombies would need to ‘live’ would be a fuel source (and the ability to use that fuel source). Zombies are no different than any other animal. We need to consume food for energy in order to run the engine, and we all have a tremendous, overpowering primal urge to obtain energy. It makes sense that living humans would be a ripe source for energy! However, I would suspect that zombies would be omnivorous like us (i.e., can eat both animals and plants for food), so I suspect they are probably snapping apples off of trees when there are no humans around.”
Kelly:“That’s really cool! I wondered if there was any biological reason zombies would want to eat humans. And it’s funny to think of them eating other foods, too. Supposing there was a parasite or disease that brought upon zombies, how long would we have until the zombies crumbled? Could weeks or months go by like in the case of Dawn of the Dead?”
