Genetically Engineered Mouse is Not Scared of Cats

Gary writes "A team from the University of Tokyo has genetically engineered a mouse that does not fear cats. By tweaking genes to disable certain functions of the olfactory bulb (the area of the brain that receives information about smells directly from olfactory receptors in the nose) the researchers were able to create a 'fearless' mouse that does not try to flee when it smells cats, foxes and other predators. 'The research suggests that the mechanism by which mammals determine whether or not to fear another animal they smell -- and whether or not to flee -- is not a higher-order cerebral function. Instead, that decision is made based on a lower-order function that is hardwired into the neural circuitry of the olfactory bulb.'"

Comments

Fearless Mice..

[kabocox]

I can't find myself fearing fearless mice. Why? Because there was most likely a very good reason for the mice that they are afraid of cats and large things that can eat them... I just can't seem to worry about these things getting loose and breeding in the wild.

It's sort of like the fear of spiders, snakes, bears, and large cats. There are very valid reasons for humans to be naturally afraid of things that can kill/harm and maybe eat us.

Re:Seems flawed...

[Kadin2048]

Well, I think that it's interconnected; there are certain smell receptors in a mouse that are hardwired to the "oh shit, run" response. They have disabled that in these mice, either by breaking the connection or disabling/removing the smell receptors more directly. The result is that the behavior is not present anymore.

That's really the interesting thing, here: they have found a genetic variation that produces a very definite, high-level behavioral change. That's pretty cool.

Although it's clear that many animals have a lot of behaviors that are 'instinctive' and must be carried genetically (which you can test by bringing an animal up in an environment that's devoid of other animals and monitoring it's behavior), it's not terribly clear exactly how they work and are transmitted. This might be one small step towards understanding a part of that.

Re:Smell only?

[xPsi]

Something tells me these mice are an evolutionary dead end... I had the same response initially as well. However, the point of the research has nothing to do with mice or fear per se, rather, from TFA, the point is to:

better understand the structure of the brain's neural circuitry responsible for processing information about the outside world . Turning off and on various inputs (like smell) is a good way to proceed. Nevertheless, as a general principle, I think most mice would agree that turning off the fear of cats would be a bad thing. And, hey, let's face it, the cats would be pretty disappointed too since giving chase is 90% of the fun for them.

It that really the conclusion?

[Elucid]

Maybe someone pointed this out already, or perhaps I am just a bozo...

If a mouse's sensorium is determined a great deal by its sense of smell... and you disable that sense of smell... its "higher-order cerebral functions" would be impaired because they would not be getting the input they require to make decisions. How can you conclude that fear in mammals is related to the oflactory sense? Other mammals may use other senses to a larger degree.

To me, this seems like the old joke about the bad scientist who concluded that a frog with all its legs removed becomes deaf because it doen't jump when he yells at it.