Since the brain is known to be plastic, is there a chance that the experience of being a convicted murderer is sufficiently different from the experience of other crimes to lead to these differences over time? Ideally, you'd want a large longitudinal study.
Brian M
Paul314 brings up a good point, the sample is already pre-selected i.e. they have committed homicide. So there is no way to know if its a cause or effect issue (stress, thought of death penalty etc).
Really need an image before the murder and after - but guess that's a bit of a tricky one!

Vincent M Tedone MD
I would like to see if there are protein aggregates in the brains of those who are guilty of abnormal behavior.
To Brian's comment, does the abnormality indicate a tendency, or did committing the act create the change in the brain? In that vein, I wonder if the results of those who have committed murder would be different than those who have taken the lives of other people in the line of duty, or in self defense?
My greatest concern for this type of research is it's misuse in the legal arena. I could easily foresee a lawyer twisting this to say, "My client was born this way so he couldn't help himself." Any sort of separation from personal responsibility is a total misread of this research. A MRI "finger print" may point to conditions being right, or better, conditions are similar for something to happen but the individual still has to choose to do it -- and it IS a choice. How do you get a sample population of those people who have considered a crime but didn't actually follow through so that you can compare?
Expanded Viewpoint
It would be good to see MRI brain scans of people as they age and see how the crenelations change over time, if they actually do so. Supposedly now, and I have not seen any MRI images to date to support this claim, but people who have undergone certain "life coaching" drills and positive mental exercises and affirmations are said to have restructured their grey matter. As to which is the cause and which is the effect here, is anybody's guess, at this point.
Adding to the comment earlier, I would also be interested in learning if this “brain research only applies to “convicted” prisoners found guilty by a jury or to all cases of individuals that have practiced homicide; self defenders, soldiers, police, intelligence workers, etc. Has the variable of being incarcerated for homicide and length of time been accounted for as well the physical, social, diet and health care environments that the individuals have been exposed to? Could this be the CAT scan update to phrenology? If this is highly predictable science then maybe we should think about “killing” the murderous “brain” in vitro. Frightening day for those that “kill” us with humor.
Eric Blenheim
Has anyone dared to test the brains of government members yet, as many have committed genocide, and still plan more?
I see absolutely no mention of friendly murderers: soldiers who killed in wartime, cops who had to shoot a perp on the streets, people who killed in self-defense, etc. That should have been a high-priority point in the study if if were unbiased and sought validity. With it completely missing, doubt is placed on both the method and outcomes of the study. And that's not to mention that it should be 100 times larger in sampling, as well. Cross culture, cross race, cross gender (all 1000?).
This sounds like something out of Minority Report, finding future criminals and arresting them prematurely. Beware of studies like these!
Jose Gros
Interesting study, but a doubt may remain on the reduced gray matter in some brain areas could be the consequence and not a root of murder. A way to know this could be an observational study, but as murders remain a rare episode, the size of cohort to be watched with brain imaging could be so huge, that costs became unaffordable. Salut +