In the movie, Slither, alien zombies that look like giant pink slugs infect humans by wiggling through victim's open mouths.
I know this sounds like it has nothing to do with “real” neuroscience but bear with me here, I've been on a zombie kick.
The slug's first line of attack is through the brain, where necessary information relating to their species is disseminated, collectively linking all infectees. The zombie collective, consequently, know their celestial history, act in unison and are in love with the same woman.
After reading about mirror neurons, I can't help but reflect on how similar we are to the Slither zombies. Not that we all love the same woman, but we are, somehow, ethereally linked.
Mirror neuron cells activate when an observer sees an action or performs it. Researchers have recently shown that even observed facial expressions and hand gestures activate this mirror neuron system in humans. So, watching someones face (or hands) move, in turn activates the same brain areas that would fire if you were to make the movements yourself.
This system is likely responsible for the rubber hand illusion (how your brain can assume possession of a fake arm) that I spoke about last posting. How mirror neurons connect us with others or synthetic others (in the case of plastic arms), is likely the basis for imitation and empathy (and may have something to do with autism). And while it is characterized by action-linked responsiveness, some suggest that it may encompass or carry over into other realms such as emotion, or taste.
The cell biologist/biochemist in me wants to dissect these special cells and look at them on the single cell level. Are they at all different than cells that are not in the “mirror neuron system?” I imagine they are the same—but the activating stimuli is an idea, rather than a sensory perception. We all know that ideas can be infectious, stimulating and somehow amorphous. Perhaps the infectious nature of ideas and our brain's response to them is what makes us part of the collective.
In the zombie comedy, “Shaun of the Dead,” 'normal' people are so zombie-like, the main characters almost miss the uprising. Perhaps if we look long enough, we'll be able to dissect out all of our zombie tendencies. Until then, watch out for giant pink slugs.
There are lots of references for the mirror neuron system--this one is publicly available
Social cognitive and affective neuroscience 2007 Mar;2(1):62-66.
