Just a couple weeks ago the Justine and Catherine MacArthur Foundation awarded a $10 million dollar grant to twelve universities to study neuroimaging and the law. The purpose of the grant is to get a better understanding of the relationship between functional neuroimaging studies and forensic issues such as competence to make decisions, criminal responsibiity and disabiity. This grant has the potential to really change the nature of psychiatric expert testimony.
The grant has three components: brain abnormalities, substance abuse and decision-making. There will be some overlap between these areas, but the general idea is to start bridging the gap between what is seen on a functional MRI and the ultimate legal questions of criminal culpability and competence. This can be a life or death question---in Roper v Simmons neuroimaging was used as evidence that juveniles should not be given the death penalty. Hopefully the MacArthur grant will shed some light on whether the degree of brain myelination in juveniles is, in fact, relevant at all to criminal responsibility. Right now the legal opinions based on neuroimaging have tended to leap a bit beyond what science has shown in my opinion.