The Brain Resting-State Functional Connectivity Underlying Violence Proneness: Is It a Reliable Marker for Neurocriminology? A Systematic Review

Abstract

Introduction: There is growing scientific interest in understanding the biological mechanisms affecting and/or underlying violent behaviors in order to develop effective treatment and prevention programs. In recent years, neuroscientific research has tried to demonstrate whether the intrinsic activity within the brain at rest in the absence of any external stimulation (resting-state functional connectivity; RSFC) could be employed as a reliable marker for several cognitive abilities and personality traits that are important in behavior regulation, particularly, proneness to violence. Aims: This review aims to highlight the association between the RSFC among specific brain structures and the predisposition to experiencing anger and/or responding to stressful and distressing situations with anger in several populations. Methods: The scientific literature was reviewed following the PRISMA quality criteria for reviews, using the following digital databases: PubMed, PsycINFO, Psicodoc, and Dialnet. Results: The identification of 181 abstracts and retrieval of 34 full texts led to the inclusion of 17 papers. The results described in our study offer a better understanding of the brain networks that might explain the tendency to experience anger. The majority of the studies highlighted that diminished RSFC between the prefrontal cortex and the amygdala might make people prone to reactive violence, but that it is also necessary to contemplate additional cortical (i.e., insula, gyrus [angular, supramarginal, temporal, fusiform, superior, and middle frontal], anterior and posterior cingulated cortex) and subcortical brain structures (i.e., hippocampus, cerebellum, ventral striatum, and nucleus centralis superior) in order to explain a phenomenon as complex as violence. Moreover, we also described the neural pathways that might underlie proactive violence and feelings of revenge, highlighting the RSFC between the OFC, ventral striatal, angular gyrus, mid-occipital cortex, and cerebellum. Conclusions. The results from this synthesis and critical analysis of RSFC findings in several populations offer guidelines for future research and for developing a more accurate model of proneness to violence, in order to create effective treatment and prevention programs.

A Systematic Review of the Effectiveness of Non-Invasive Brain Stimulation Techniques to Reduce Violence Proneness by Interfering in Anger and Irritability

“…We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) quality criteria for reviews to conduct this systematic review [5,6,22,23]. A literature search was performed through the following databases: PsycINFO, PubMed, Dialnet, Psicodoc, Web of Knowledge, and the Cochrane Library.…”

“…Moreover, many patients tend to abandon the intervention before it ends [4]. Thus, combining the above-mentioned treatments with pharmacological strategies, such as antidepressants, mood stabilizers, antipsychotics, and beta-blockers has been recommended and tends to have long-lasting effects [5,6]. Unfortunately, in many patients, these drugs tend to present side-effects, such as loss of sexual desire, weight gain, and insomnia, among others, during the initial stages of treatment [6][7][8].…”

“…Moreover, it has been suggested that their effects are capable of inducing changes in cortical excitability that can be maintained for days, but it is less clear how long these effects last after this period [17]. Moreover, it should be highlighted that cognitive processes and behaviour are sustained by complex neural networks made up of cortical and subcortical structures [5]. Therefore, the application of changing magnetic pulses and/or electric currents over the brain's cortex might partly modulate these processes.…”

“…Many authors have identified two specific cortical structures, the prefrontal cortex (PFC) and the temporal lobe, as important for behavioural regulation. In this regard, violence proneness is commonly present after registering injuries (e.g., tumours, traumatic brain injuries, brain haemorrhages) in these cortical structures [3][4][5]. In fact, specific traumas in one or both of these brain structures might facilitate outbursts and violent reactions due to difficulties in inhibiting limbic irritability [3][4][5].…”

“…Because these two types of reactions are explained by different cognitive processes, it is logical to conclude that their underlying brain structures would differ. Proactive reactions tend to be related to an increased activation of the ventral striatal and the angular gyrus [5]. Nonetheless, it is not well-understood whether non-invasive brain stimulation techniques would be appropriate to reduce specific behavioural dysregulations, such as violence proneness, by interfering in current brain networks by applying magnetic pulses and/or current flows.…”