PZ linked to this, which I didn't include: The neuropsychology of zombies
George Romero, the man behind "Night of the Living Dead," may not be a neuroscientist, but he and the zombie-auteurs who followed him have an uncanny understanding of the brain works, according to Schlozman. The first part is fairly intuitive. Zombies are humans whose own brains have regressed to the level of a crocodile's, the filters between primal urges and action entirely erased. (See flesh, eat flesh.) In contrast, the protagonists in zombie films, the survivors, retain the brain functions that tamp down primal reactions before passing them on to the higher cortical regions. They think before they act -- at first.
And that's the crux of one of Schlozman's arguments: The story changes as the situation grows grimmer. Here, the professor draws on "mirror neuron" theory, which holds that humans are hard-wired to reflect the psychological states of the people around them. (Show a test subject a short film of a face displaying disgust, or pleasure, and regions of the brain associated with those feelings activate in the subject.)
Unable to relate to the hordes of undead, the survivors in zombie films enter a spiral of despair, feeding off the panic and hopelessness of the uninfected people around them. At the bottom of the spiral comes a crucial psychological moment, Schlozman tells Brainiac, one that you'll find in most zombie flicks:
The protagonists rush out of whatever symbolic structure they happen to be walled up in (churches, malls, etc) and rather than letting the Zombies simply devour them, they try to kill as many Zombies as they can even though they know it's useless! They fully expect to die.