Anyone with half a brain wouldn't be a zombie.
Experts say that in order for a person to go from being a normal functioning member of society into a ravenous, shambling creature requires something to happen to two different parts of the human brain.
Dr. Steven Schlozman, Assistant Professor of Psychiatry at Harvard Medical School and author of “The Zombie Autopsies” recently studied the zombie brain for "Zombie Apocalypse," a special debuting Dec. 18 on the Discovery Channel that examines the science behind this end-of-the-world scenario.
He said that for a human to become a zombie, they would have to have some dysfunction in both the frontal lobe and cerebellum.
"The frontal lobe is what helps us to understand complex problems. It's called the executive functioning center," Schlozman said. "It allows you to do three or four things at the same time and it also, importantly, allows you to distinguish between what's the right thing to do and the wrong thing to do. Some people might even say it helps you distinguish between good and evil."
The cerebellum is the brain region that is responsible for balance and is the area that is affected when humans, say, drink too much.
"Some would have to say that watching the way zombies move, the way they shamble, that this region is not working right," Schlozman added.
To be fair, Schlozman is of two minds about the concept of a zombie apocalypse. He is a lifelong fan of zombie movies and enjoys using them as a way to introduce the basics of neuroscience to the general audience, but he also wants people to understand that the likelihood of a so-called zombie outbreak is very very unlikely.
"For a zombie outbreak to reach a pandemic level, it needs a contagion," he explained to The Huffington Post. "Biting would work, but only if the dead came back to life. That doesn't work."
Schlozman said that the contagion could also be spread from an airborne bug. For it to make people behave like zombies, it would have to invade parts of the brain selectively so that it only affects regions like the cerebellum that control motor movement.
"This contagion would have to make those affected hungry," Schlozman said. "That's a hard one because when you're sick, you're not hungry."
Although Schlozman thinks an actual zombie outbreak is nigh impossible, he said the attention surrounding an occurance has been a godsend to people in the scientific community who are trying to generate more interest in the field.
"The public likes pop culture and this gets people through the back door and gets them thinking outside the box," he said.
One of those people who is thinking outside of the box is Wisconsin-based high school teacher Shawn Beatty, who appears in the show.
Beatty teaches Japanese by day, and does zombie prepping during his off-hours, even running a Zombie Defense League club at his school.
"I am 70 percent sure some kind of pandemic will happen," he told HuffPost. "We're over capacity and need to reduce our population. Other animals self-regulate, but no one wants to volunteer, and things like mandatory birth control are Draconian."
Beatty says technology and medicine have made people better, but the overall problem is getting worse and it is only a matter of time before something like the ebola virus attacks humans en masse.
"I believe any zombie outbreak would be disease-based," he said. "One that causes high fevers could cause people to walk like zombies or maybe a bacteria that affects the brain like bath salts."
The crowd mentality associated with zombies and a zombie outbreak are exactly what Beatty aims to avoid, which is why he suggests using counter-intuitive ways to prepare for the worst, such as buying food for disaster kits from pet stores.
"If an outbreak happens, everyone will be going to Walmart for medicine and food, but the pet store and the vet also have food and medicine," he told HuffPost. "The standards for pet food are more stringent than humans. It may not taste great, but it will keep you alive.
"Same with guns. While everyone heads to the gun store, no one will be at the archery store buying crossbows."