Toxoplasma Gondii is a parasite with a problem. It hangs out in gardens, parks and forests, but the survival of it and its species depends on somehow getting inside stomach of a cat.
This is not easy for a single-celled animal with no legs. It can’t get a running start and jump into the cat’s mouth. It can’t call microbial Uber.
Toxoplasma gondii, or “Toxo” as its fans call it, has only one way to get into the belly of a cat: true freaking love.
Your average mouse, when it sees a cat, is like a Chicago politician seeing the FBI. “Damn! I’m outa here!” Conversely, when your average mouse sees a mouse of the opposite sex, or whatever gender that mouse is attracted to, it thinks, “Damn! Let me get to know that piece of cheese!”
The “Damn” reaction comes from part of the brain called the amygdala. The amygdala is about arousal. When they deal out the poker hands, you look at yours and see three aces and two kings, you think, “Damn!” Your heart races, your palms get sweaty and you start identifying with Donald Trump. That’s your amygdala responding to opportunity. Your amygdala is why it takes work to develop a poker face. But if you are driving and suddenly see blue lights flashing behind you, you also think, “Damn!” Your heart pounds, palms get sweaty and the rest, and all you can think of is “Ferguson, Missouri, Ferguson, Missouri!” That’s your amygdala responding to danger.
It’s on the amygdala that toxoplasma gondii performs its parasitic mind trick.
Toxo can precisely locate the area of mouse amygdala that makes it afraid of cats and turn it off. An infected mouse is still afraid of lights, electric shocks, and graduate students but not of cats. In fact, they fall in love with them. To a toxo-infected mouse, the smell of cat is like a bacon double cheeseburger with a side order of cash.
Love turns the mouse into a suicide snack. It rushes toward the cat, the cat eats it, toxo reproduces in the cat’s gut, gets all intimate with cat poop, and gets dropped onto the soil and the cycle begins anew.
There is good but contested science that shows toxo also causes humans to do dumb shit. Studies have shown Toxo infected people are 2.5 times more likely to be involved in traffic accidents. Others show toxo-infected women take more sexual risks, for which some say, “Thank you, Toxo!”
So the next time you watch Jackass or you see some human behavior that make you ask, “What was on their minds?” a good first question might be, “What is in their brains?”