In jail last week, we found ourselves discussing mind control.  Ants that haul infected comrades away from the colony – otherwise, the zombie will climb above the colony before a Cordyceps fruiting body bursts from its spine, raining spores down onto everyone below, causing them all to die.

Several parasites, including Toxoplasma gondii, are known to change behaviors by infecting the brain.  I’ve written about Toxo and the possibility of using cat shit as a nutritional supplement previously – this parasite seems to make its victims happier (it secretes a rate-limiting enzyme for dopamine synthesis), braver, and more attractive.

I told the guys that I used to think mind control was super-terrifying – suddenly your choices are not quite your own! – but I’ve since realized that body control is even more terrifying.

We’d thought that each fungus that makes ants act funny was taking over their brains.  But we were wrong.  The Ophiocordyceps fungus is not controlling the brains of its victims – instead, the fungus spreads through the body and connects directly to muscle fibers.  The fungus leaves an ant’s brain intact but takes away its choices, contracting muscles to make the ant do its bidding while the poor creature can only gaze in horror at what it’s being forced to do.

If a zombie master corrupts your brain and forces you to obey, at least you won’t be there to watch.  Far worse to be trapped behind the window of your eyes, unable to control the actions that your shell is taking in the world.

A sense of free will is so important to our well-being that human brains seem to include modules that graft a perception of volition onto our reflex actions.  Because it takes so long for messages to be relayed to the central processing unit of our brains and back outward to our limbs, our bodies often act before we’ve had a chance to consciously think about what we’re doing.  Our actions typically begin a few hundred milliseconds before we subjectively experience a decision.

Then, the brain’s storytelling function kicks into gear – we explain to ourselves why we chose to do the thing that we’ve already begun doing.

If something goes wrong at that stage, we feel awful.  People report that their bodies have “gone rogue.”  If you use a targeted magnetic pulse to sway a right-handed person to do a simple task left-handed, that person probably won’t notice anything amiss.  The storytelling part of our brain hardly cares what we do – it can come up with a compelling rationalization for almost any action.

“Well, I chose to use my left hand because … “

But if you use a targeted magnetic pulse to incapacitate the brain’s internal storyteller?  The sensation apparently feels like demonic possession.  Our own choices are nightmarish when severed from a story.