One could go through an entire judicial career without confronting the issue of brain scan evidence, but if you do, a recent piece is a great position to start your education:  Deborah W. Denno (Fordham University School of Law) has posted Concocting Criminal Intent (Georgetown Law Journal, Vol. 105, pp. 323-78 (2017)) on SSRN.

Here is the abstract:

My empirical study, which examines neuroscience evidence in 800 criminal cases over the course of two decades, is the first to determine how, when, and why victim brain scan evidence is introduced and used in court. My study reveals that although courts commonly rely on brain scans to show the extent of a victim’s injury, the actual application of this neuroscience evidence extends far beyond the purpose for which it is admitted. Indeed, victim brain scans are introduced primarily by prosecutors, and nearly half of these cases are based on medical expert testimony that the victims suffer from shaken baby syndrome, a medical diagnosis with controversial scientific underpinnings and distorted legal ramifications. The diagnosis often successfully serves as the sole foundation for a prosecutor’s case, with no proof of the defendant’s act or intent beyond the victim’s brain scan and the accompanying medical expert testimony. Shaken baby syndrome cases thus portray a troubling phenomenon in which the key element of mens rea is either unclear or overlooked altogether and prosecutors are permitted to concoct intent out of brain scans that were admitted for the sole purpose of presenting the victim’s injury. My study further reveals that shaken baby syndrome cases are merely the more transparent examples of the criminal justice system’s failure to deal adequately with the surging influx of neuroscience evidence into the courtroom. Shaken baby cases thus represent a microcosm of prosecutorial misuse of victim neuroscience evidence more generally, particularly when the evidence is employed to determine a defendant’s mental state.