Neurobiology of the borderline personality disorder: Experts have used MRI scans to study the brains of people with borderline personality disorder. MRI scans use strong magnetic fields and radio waves to construct a detailed image of the inside of the body. The scans unearthed that in lots of people with borderline personality disorder, three regions of the brain were either lesser than expected or had atypical grades of activity. These locations were: 1. the amygdala: which plays an essential role in regulating feelings, especially the more "negative" feelings, for instance dread, aggression and angst, 2. the hippocampus: which assists manage action and self-control, 3. the orbitofrontal cortex: which is involved in preparing and evaluation making. problems with these parts of the brain may well make contributions to signs of borderline personality disorder. The development of these regions of the brain is influenced by your early childhood. These locations of your brain are also concerned for emotional control, which may be the reason for some of the problems people with borderline personality disorder have in close relationships.