Researchers Show How The Brain Turns On Innate Behavior

Science Daily ^ | July 28, 2006 | University of California - Riverside

[Maelstorm]

UCR researchers have made a major leap forward in understanding how the brain programs innate behavior. The discovery could have future applications in engineering new behaviors in animals and intelligent robots.

Innate or "instinctive" behaviors are inborn and do not require learning or prior experience to be performed. Examples include courtship and sexual behaviors, escape and defensive maneuvers, and aggression.

Using the common fruit fly as a model organism, the researchers found through laboratory experiments that the innate behavior is initiated by a "command" hormone that orchestrates activities in discrete groups of peptide neurons in the brain. Peptide neurons are brain cells that release small proteins to communicate with other brain cells and the body.

The researchers report that the command hormone, called ecdysis-triggering hormone or ETH, activates discrete groups of brain peptide neurons in a stepwise manner, making the fruit fly perform a well-defined sequence of behaviors. The researchers propose that similar mechanisms could account for innate behaviors in other animals and even humans.

Study results appear as the cover article in this week's issue of Current Biology.

"To our knowledge, we are the first to describe how a circulating hormone turns on sequential steps of an innate behavior by inducing programmed release of brain chemicals," said Young-Joon Kim, a postgraduate researcher in UCR's Department of Entomology working with Michael Adams, professor of cell biology and neuroscience and professor of entomology, and the first author of the paper. "It is well known that such behaviors -- for example, sexual behavior or those related to aggression, escape or defense -- are programmed in the brain, and all are laid down in the genome. We found that not only do steps involved in innate behavior match exactly with discrete activities of the neurons in the brain but also that specific groups of peptide neurons are activated at very precise times, leading to each successive step of the behavioral sequence."

In their experiments, which involved state of the art imaging techniques that helped the researchers see activated neurons light up in the fruit fly brain, the researchers specifically focused on arthropods, such as insects. Insects pass through multiple developmental stages during their life history. Each transition requires molting, a process in which a new exoskeleton (or cuticle) is produced and the old is shed. Insects shed the old cuticle by performing an innate behavior consisting of three distinct steps lasting about 100 minutes in total.

First, the researchers described the ecdysis sequence, an innate behavior that insects perform to escape their old cuticle, and showed that the insect initiates behavior shortly after appearance of ETH in the blood. The researchers then demonstrated that injection of the hormone into an animal generates the same behavior. To investigate mechanisms underlying this hormone-induced behavior, they used real-time imaging techniques to reveal activities in discrete sets of peptide neurons at very precise times, which corresponded to each successive step of the behavioral sequence. The researchers confirmed the results by showing that behavioral steps disappear or are altered upon killing certain groups of brain neurons with genetic tools.

"Our results apply not only to insects; they also may provide insights into how, in general, the mammalian brain programs behavior, and how it and the body schedule events," said Adams, who led the research team. "By understanding how innate behavior is wired in the brain, it becomes possible to manipulate behavior -- change its order, delay it or even eliminate it altogether -- all of which opens up ethical questions as to whether scientists should, or would want to, engineer behavior in this way in the future."

The fruit fly is a powerful tool and a classic laboratory model for understanding human diseases and genetics because it shares many genes and biochemical pathways with humans.

Besides Kim and Adams, UCR's Dusan Zitnan, C. Giovanni Galizia and Kook-Ho Cho collaborated on the study which was supported by a grant from the National Institutes of Health and a Rotary Foundation Ambassadorial Scholarship to Kim.

[Maelstorm]

I was wondering when someone would get around to figuring this out. Now the question is how to you program these built in behaviors?

[FairOpinion]

PING

[nmh]

It sure wasn't "evolution"!

It was God.

[GSlob]

"Now the question is how do you program these built in behaviors?"
By writing [or re-writing] a genome. In a few centuries it might become possible - one would be able to dial a baby with, say, Michelangelo level genius, or other pre-determined and desirable characteristics. Life will become a lot of fun, assuming that septic tanks will drive and operate themselves [and the same applies for all other drudgery].

[butternut_squash_bisque]

"Using the common fruit fly as a model organism..."

Substitute liberal-demokkkRATs when they run out of flies. Same thing.

[Bad~Rodeo]

Gee and all this time I tought it had to do with one's social enviroment and or religious up-bringing, ie: brain washing, silly me.

[Maelstorm]

I think this really opens up a lot of questions and really complicates things for those who wish to ignore the clear evidence of intricate design in the biological world. I noticed this when I was researching the behavior of "cowbirds". It struck me that such behavior arising from natural selection was a real leap. Many coevolutionary relationships present this problem whether they be parasitic or symbiotic or a combination of the two. It will be interesting to see where this goes but of course this brings up the possibility of creating far more effective behavior control substances for use in treatments or other less benign applications.

http://inin.essortment.com/cowbird_rkws.htm

[silverleaf]

Someday a cure for homosexuality?

[adorno]

It amazes me that we humans have to learn some behaviours in order to learn to get along with the world or in many cases, to save our lives.

My two cats, at the slightest distant rumbling of an oncoming thunder-storm instandly and hurriedly head to my downstairs bathroom for their "protection". We humans had to be taught to get to the sturdiest room in the house in case of possible destructive danger to the house.

Aside from humans having superior intelligence, which animal has the superior weapons at their disposal? The animal that instinctively does what's necessary or the animal that has to learn the same behaviour?

[MHGinTN]

The researchers report that the command hormone, called ecdysis-triggering hormone or ETH, activates discrete groups of brain peptide neurons in a stepwise manner, making the fruit fly perform a well-defined sequence of behaviors. The researchers propose that similar mechanisms could account for innate behaviors in other animals and even humans. A major leap of understanding 'how' it is accomplished? I'm waiting for soemone to define the phase shift from biochemical processes to 'behavior' that enhances survival. A possible analogy is a computer taking in data sets and then transforming the data sets to output a motion and function which aids the survival of the computer but which is a qualitative phase shift from the data sets input. When science can define that phase shift process as well as they define the electron jump in energy states with the exclusionary principle and energy shells, then we'll really be getting somewhere.

[Maelstorm]

I think that is pretty straightforward. All that junk DNA may be the storage place for behavioral data. The question I have is what is the mechanism for encoding new behaviors naturally.
Simple mutations and natural selection as defined currently seems to be lacking where this is concerned.

http://www.nsf.gov/news/news_summ.jsp?cntn_id=104238

[MHGinTN]

It is almost as if the cats have lived before and experienced death from the oncoming phenomenon and somehow carry that memory through into successive lives. I have one cat who does similar to your cats, but the other cat igmores the exact same phenomenon the first cats is reacting to.

[GSlob]

Wait a few centuries. What is being done now is trying to read a genome at the level of reading abilities of a child of 4 years. First, we'll get to a facile reading, then [or simultaneously] to understanding of the text - on many levels, literary style included. And then [or again, overlapping] - to learning to write our own texts. It's not enough to know where it is - one needs to know why it is there and not [i.e. what would happen if it were] someplace else, and how it works while there.

[sourcery]

I predict defense attorneys will try to use this information to show that the criminal behavior of their clients was "innate," and so beyond their control.

[patton]

Where, exactly, do you want your septic tank to drive to?

[Gumlegs]

No ... there are some things a fruit fly won't do.

[GSlob]

Should have been "truck". Sorry for the error. From the waste source and to the treatment facility.

[butternut_squash_bisque]

You're absolutely right, G: fruit flies have integrity; lib-dem trash, don't. My bad.

[patton]

Hey, it was worth a laugh. ;)

[nitzy]

I wonder how long it will take the egg head liberal educrats who run the university research labs to delete the common sense conservatism gene.