Orbito-frontal cortex volumes in patients with antisocial personality disorder

A proteomic signature for CNS adaptations to the valence of environmental stimulation

Environmental Enrichment leads to a significant improvement in long-term performance across a range of cognitive functions in mammals and it has been shown to produce an increased synaptic density and neurogenesis. Nevertheless it is still an open question as to whether some key aspects of spatial learning & memory and procedural learning might be embodied by different molecular pathways to those of social cognition. Associated with synaptic changes and potentially underlying conditions, the Ras-ERK pathway has been proposed to be the primary mediator of in vivo adaptations to environmental enrichment, acting via the downstream Ras-ERK signalling kinase MSK1 and the transcription factor CREB. Herein, we show that valence of environmental stimulation increased social competition and that this is associated with a specific proteomic signature in the frontal lobe but notably not in the hippocampus. Specifically, we show that altering the valence of environmental stimuli affected the level of social competition, with mice from negatively enriched environments winning significantly more encounters-even though mice from positive were bigger and should display dominance. This behavioural phenotype was accompanied by changes in the proteome of the fronto-ventral pole of the brain, with a differential increase in the relative abundance of proteins involved in the mitochondrial metabolic processes of the TCA cycle and respiratory processes. Investigation of this proteomic signature may pave the way for the elucidation of novel pathways underpinning the behavioural changes caused by negative enrichment and further out understanding of conditions whose core feature is increased social competition.

Reduced hippocampus and amygdala volumes in antisocial personality disorder

In the present paper, we aimed to investigate hippocampus and amygdala volumes in a group of patients with antisocial personality disorder and hypothesized that hippocampus and amygdala volume alterations would be observed. It was measured hippocampus and amygdala volumes of twenty patients with antisocial personality disorder and those of healthy control subjects. We found that both sides of hippocampus and amygdala volumes of patients with antisocial personality disorder were statistically significantly reduced compared to those healthy control subjects, and observed statistically important correlations between the left and right and left hippocampus and left amygdala volumes, and age, some results on scale scores. Consequently, the present study suggest that hippocampus and amygdala volumes of patients with antisocial personality disorder had abnormally smaller than those of healthy control subjects, considering that these abnormalities might be associated with at least some clinical features of antisocial personality disorder. However, longitudinal studies are needed to assess causality of this relationship.