Parasites That Brainwash Their Host | Hacker News Reader

Parasites That Brainwash Their Host

scienceblogs.com

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Cysticercosis (pork tapeworm) can cause marked personality changes in humans when cysts form in the brain.

http://en.wikipedia.org/wiki/Cysticercosis

True, but what makes a creature like the gordian worm more interesting is that there's a reproductive benefit, for the parasite, inherent to the behavioral changes induced. Do the pork tapeworms benefit by causing this problem in humans, or is it just an incidental side effect? It seems to me to be the latter.

Same for toxoplasmosis, although the behavioral changes in humans appear to be secondary to the changes in mice.

http://en.wikipedia.org/wiki/Toxoplasmosis#Behavioral_change...

I think I saw that on an episode of House M.D.

As the Wikipedia article notes, it was the pilot episode.

Robert Sapolsky has a fascinating article on this topic called "Bugs in the Brain." I couldn't remember the article title, but I just had to google for the terms:

sapolsky french kiss polar bear

and that did it. Read the article and find out why. It's classic Sapolsky.

http://www.sciam.com/article.cfm?id=bugs-in-the-brain

hmm, no comments yet? I'm assuming its one of those articles that speaks for itself. I know I read it last year, but watching it/reading it all over again was just as fascinating. The fact that similar proteins were used in the fungi, which coordinated with the actual organism was pretty amazing. It's almost as if evolution hacked itself to brainwash an organism. Kind of nuts...

There are some who believe that fungi and plants like marijuana and psilocybin mushrooms actually co-evolved with mammalian nervous systems, as opposed to the more common theory that their psychoactive chemicals evolved as pesticides (like caffeine, which is deadly to insects). For example, one theory is that psilocybin developed to inspire herbivorous animals to break out of their routines and seek new ranges, defecating over a wider area and creating a larger habitat for the mushrooms. Terrence McKenna, though it should be said that he was far from a skeptical researcher, believed that psilocybin actually drove human evolution; for example, drug-induced synesthesia, mapping concepts to symbols, is his explanation for the emergence of language. (However, language has been shown to emerge naturally in the absence of psychedelic chemicals, so I find this to be particularly far-fetched.)

Language has been shown to emerge naturally? I'm not sure what you're referring to, could you provide a link?

One major example that has stuck with me in the case of Nicaraguan Sign Language, which was spontaneously developed by a group of deaf schoolchildren. Wikipedia has an article on it, and Stephen Pinker discusses the phenomenon at length in his book The Language Instinct.

Yeah, but that doesn't show how language evolved, it just shows that language is innate in modern humans rather than a purely social construct.

That's not what you asked. You asked for evidence that language "has been shown to emerge naturally". The case of NSL is such evidence.

It has long been known that cats carry a sort of mind-altering parasite (toxoplasmosis).

The parasite has been shown to affect behavioral changes in rats, causing them to recklessly seek out areas marked with cat urine (which causes panic in normal rats). So the parasite seems to help its original host organism in their common interest of staying alive.

There's more on that here: http://www.livescience.com/technology/060210_technovelgy.htm...

Biology freaks me the hell out. It seems like every article I read about it has some new horror to regale me with. It's messy and chaotic and squishy and bizarre.

Give me the spare elegance of math or physics or computation any day. That I can deal with.

Could someone have said "that page starts off with a huge close up of an insect"? I freaked as soon as it popped up and had to close my eyes.

Gross. This stuff's used in Chinese medicine. My parents have a friend who drinks a tea made from this fungus.

Mushrooms are fungi, you know.

I do know. The mushrooms on my pizza, however, weren't grown by planting spores in a poor animal's head and growing and growing until its exoskeleton cracked.

This is an awesome example, as the article says, of the extended phenotype of Prof. Richard Dawkins. The genes of the worm parasite for example, produce proteins which manipulate the central nervous system of the grasshopper, ergo, one has the genes of one organism affecting the behavior of another organism. I'm a big Dawkins fan, ever since I got 'The Selfish Gene'. I am particularly intrigued by the ability of the parasite to escape once its host has been preyed upon, so if a frog eats a grasshopper that has a worm in it, the worm can escape both the carcass of the grasshopper and the frog. In the end, the grasshopper becomes nothing more or less than the worm's mechanism of replication. One could view this as a restricted class of cases, however, I think one can generalize this by saying as some do, that in fact all life from parasites to ourselves is simply a form of intermediaries to preserve a relatively restricted set of phenotypes, i.e., we are indeed, like the grasshopper, "gene carrying robots". Of course I think I take a certain geeky pleasure from this knowledge, to be able to disabuse people of their quaint, deluded notions of life having mystical attributes, when in fact it is finally speaking a fancy chemical process brought about to preserve genomes, this, and nothing more! :-)

* Of course I think I take a certain geeky pleasure from this knowledge, to be able to disabuse people of their quaint, deluded notions of life having mystical attributes*

1. Evolution does not disprove a vitalistic or "mystical" explanation for the origin and progress of life.

2. The "mystical" position has lost no ground to scientific advances, although rigid systems of belief (e.g. creationism) have. Atheism has existed for thousands of years; presumably, it's as old as theism. The partial retreat of Christianity from mainstream Euro-American life has to do with cultural forces, not science.

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