Advances in our understanding of the brain have turned neuroscience into one of the hottest frontiers in research, and in ethics. (See "Beyond the Brain.")

Obama asked the bioethics council to look into what sort of moral dilemmas might arise from the newfound abilities to peer into the workings of the human mind promised by his brain-mapping proposal, and by neuroscience overall.

What are the big questions? We asked Hank Greely, a bioethics and genetics expert at Stanford University's Law School, what he sees as being the five big questions in neuroscience. Here are his insights:

1. Prediction: using neuroscience to predict peoples' fate or actions.

We are spending a lot of research dollars on the question of whether Dad, or I, will get Alzheimer's. What is going to happen when we can really predict that? There will be tremendous implications for families and the medical system, in terms of intervention or treatment.

Another question is crime. What about when we can tell whose brains indicate they are more likely to commit or recommit a crime when people are released from jail? Who is going to recommend or deny a brain scan for every criminal case?

Most likely, these brain results will just be added to other evidence in criminal cases. But if neuroscience adds yet another predictive element to when releases [from prison occur] or sentences end, it will have big effects on preventive retention or preventive therapy for the incarcerated.

2. Mind reading: using neuroscience as a lie detector or to see emotional states.

When I first started saying "mind reading," I thought a lot of my neuroscientist friends would object. But many of them say, yes, that is right, it is like that. A study involving MIT undergraduates was able to tell when they were visualizing a face or a place with 85 percent accuracy, for example. That's pretty good.

Where this will really make a difference is in contacting quadriplegics with the most severe paralysis—"locked in" individuals. We will be able to put people thought to have been in a persistent vegetative state in a [brain] scanner and try to talk to them.

Lie detection raises a host of legal, ethical, and social questions. Only one company is left doing this—NoLieMRI. They are seen as problematic because they don't publish their methods or results. But there is a lot of interest in the technology from the Defense Department, which wants to move away from the polygraph to other ways to do lie detection.

In court, where you will probably first see mind reading is with disability claims—whether people are really feeling pain for Social Security disability claims for lower back pain. Hundreds of thousands of people are making these claims. Some perhaps aren't really in pain. We don't have a good way to tell the difference, but if we did, that would matter.

3. Responsibility: using neuroscience to determine whether people have free will.

I have some neuroscientists who think the effect of their science will be to make the court system disappear. It will show that people have no real "free will" and that people are not truly responsible for their actions. "My brain made me do it" … I don't know any lawyers who believe this will happen.

But there is one particular case, which took place in Charlottesville, Virginia, of a 40-year-old man who suddenly became interested in pornography and moved to child pornography and then groped his 12-year-old stepdaughter. The Tuesday before his sentencing he complained of headaches, couldn't read, he blacked out. And they took him to the emergency room.

They found a tumor the size of a chicken egg on a part of his brain called the left frontal lobe [implicated in studies as being involved with judgment and cognition]. They removed the tumor and the impulses went away.

Ten months later he tells his probation officer that the impulses are coming back. They x-ray him and find that the tumor has returned. They remove the tumor again and he hasn't been rearrested in the last two to three years.

Ironically, we may see a lot of court cases involving brain abnormalities where people claim their lawyer was ineffective. "I should have had a brain scan," they will tell the jury.

4. Treatment: using neuroscience in medical care.

We are not giving billions of dollars to neuroscientists to study whatever interests them, but for treatments for diseases such as Parkinson's. That is what is driving the funding for neuroscience.

We have to ask careful questions, however, about claims of treatment to avert or cure diseases such as opiate addiction. Could a judge order someone to get treatment based on a brain scan, or is the brain sacred? To what extent can parents force children to get treatments based on neuroscience?

As our basic medical knowledge improves, we will see dual uses spread away from cures for Alzheimer's and Parkinson's as we learn more about how to fundamentally change others.

5. Enhancement: using neuroscience to juice our capabilities.

You most often think about college kidsusing Adderall or Ritalin to give themselves a brain boost. There isn't a lot of evidence this helps, aside from keeping them awake.

But what if it does work? Is it fair to the kid who doesn't get a brain enhancement? Or what if it only works long enough to pass your medical exam—should that person be practicing medicine? Will we have to pee in a cup before finals?

I think that in memories is where we will see neuroscience matter. So much is being done on memory in connection with Alzheimer's, but also with age-appropriate memory loss. I would take a pill in an instant to have a memory as sharp as I recall it was when I was younger.

Last, we asked Greeley if neuroscience would result in ethics becoming more brain-based and moving away from the old moral questions.

No, I see neuroscience raising questions similar to any technology, although they will be fundamental ones because of the importance of the brain to our sense of self.

For any technology there are two questions you need to ask:

Does it work? It is easy to get carried away with the science-fiction scenarios and just assume it works, which may encourage giving too much credibility to a technology.

The other question is, if it does work, what now? There will be benefits and risks to any technology. It is really important to focus on both questions—not to focus on just one first—to give thought to both before it is too late to think about either one.

The interview has been edited and condensed.