This could go in biology, but the implications of this study on human behavior and addiction is really interesting so I put it here.

Scientists found that the brains of rats who chose cocaine had more lasting brain changes than rats who simply were injected with cocaine. IOW if you can choose when and if you get the addictive substance you get a deeper groove in your brain - writing metaphorically, of course.

http://www.sciam.com/article.cfm?id=cocaine-addiction-stems-from-desire

SA that could be because its a true adiction rather than an injection at set times.

Take morphine for an example, do you think an adict would show more symptioms than someone being treated with morphine? of course they would.

I dont know how you get from there to that they "chose" the adiction however

SA that could be because its a true adiction rather than an injection at set times.

Take morphine for an example, do you think an adict would show more symptioms than someone being treated with morphine? of course they would.

I dont know how you get from there to that they "chose" the adiction howeverPoor wording on my part. I meant that they were choosing to take the cocaine as opposed to the other rats that were passive receivers.

As far as your main point.....

We have two mammals one, by choice, ingests a chemical.
The other is given the chemical.

Their brains are affected quite differently.
The first has brain changes that last longer than the second. Significantly longer.

So we are not simply passive machines being affected by chemicals:

Place Xml./liter of _________ in the bloodstream and the person will___________

The context and attitude of the receiver changes the way the body, at the very least the brain, is affected by the chemical.

To turn it to a positive context I would say the study might have implications on education.

If Child A sits at his desk and is given a social studies lesson at 10am every weekday, his brain may show less lasting changes than
Child B
who is encouraged to find something in social studies or an angle on it that actually interests him or her.

Or in relation to addicts: Morphine programs should be strictly controlled around time. Addicts should have a very tiny window in which they can receive their morphine. Perhaps even a home visit would be best. The program choses when, period.

I think it would have affects on the way pain medication would be administered in relation to patients in pain.

But I am more interested in the general issue: machine like chemical+brain analyses are insufficient, perhaps in relation to a much wider range of drugs and even the broad category of 'stimuli.'

morphine IS injected by time (mostly). The only real exceptions are emergency situations where there is no base line and palitive care where conquences dont come into the piture. Chronic pain management (non palitive) always controls dose by time.

There is one thing your quotes havent said though (i cant access your artical from here) and that is wether the adicted mice were able to access a higher dose. For instance did they keep going back ever 5 min while the injected mice were given set one hour doses