Aberrant brain gray matter in murderers

Abstract

Homicide is a significant societal problem with economic costs in the billions of dollars annually and incalculable emotional impact on victims and society. Despite this high burden, we know very little about the neuroscience of individuals who commit homicide. Here we examine brain gray matter differences in incarcerated adult males who have committed homicide (n=203) compared to other non-homicide offenders (n = 605; total n = 808). Homicide offenders' show reduced gray matter in brain areas critical for behavioral control and social cognition compared with subsets of other violent and non-violent offenders. This demonstrates, for the first time, that unique brain abnormalities may distinguish offenders who kill from other serious violent offenders and nonviolent antisocial individuals.

Cerebellar Grey Matter Volumes in Reactive Aggression and Impulsivity in Healthy Volunteers

“…Additionally, structural voxel-based morphometry (VBM) and volumetry studies have provided evidence for structural cerebellar grey matter irregularities in the context of both impulsivity and aggression. In violent offenders, for example, several studies have found enhanced grey matter volumes in the right cerebellum and decreased volumes in the left cerebellum as compared to healthy controls [33][34][35][36][37]. By contrast, volume reductions of the right hemisphere [33] and total volume decreases of the cerebellum have been reported in violent offenders [38,39].…”

Neuroscience, Empathy, and Violent Crime in an Incarcerated Population: A Narrative Review

“…However, the targets and methods used in each study were varied. Of the seven empirical studies reviewed, two ( Sajous-Turner et al, 2019 ; Hofhansel et al, 2020 ) used the same method: MRI for voxel based morphometric analysis of gray matter volume. Both studies confirm that adult males convicted of violent crimes had gray matter reductions in the prefrontal cortex and temporal gyrus, areas consistently implicated in emotional control, antisocial behavior, and reactive aggression.…”

“…As Raine (2018) mentions in his review, one of the biggest weaknesses of the current neuromoral theory is its lack of incorporation of social circumstances. The heterogeneity of violent behavior and crimes exhibited by the incarcerated individuals studied makes it difficult to match and include a control community sample, as one study found ( Sajous-Turner et al, 2019 ). Additionally, the studies reviewed cannot account for whether the setting in which their subjects are incarcerated influences the results that are attributed to psychopathy, callous-unemotional traits, and violent behavior (i.e., whether institutionalization causes violence and exacerbates psychopathic traits or vice versa).…”

“…Another study from 2019 ( Sajous-Turner et al, 2019 ) reported findings on gray matter volume in three groups of adult incarcerated males: those who had committed homicide, those who had committed violent crimes but not homicide, and those who had committed minimally violent or non-violent crimes. MRI scans and subsequent statistical analysis revealed that males convicted of violent crimes had large deficits in the orbitofrontal/ventromedial prefrontal cortex, anterior temporal cortex, insula, medial prefrontal/anterior cingulate and precuneus/posterior cingulate cortex compared to males convicted of non-homicidal and minimally violent crimes.…”

Inside the Brain of a Killer: The Ethics of Neuroimaging in a Criminal Conviction

“…Further, a recent study investigating the difference in grey matter volume of violent versus non-violent criminals found that those who have committed a homicide have reduced grey matter in the regions of the brain associated with emotional processing, behavioral control and social cognition. Including the MRI scans of over 800 prisoners, the study found a significant difference in grey matter volume in the orbitofrontal cortex and anterior temporal lobes in the perpetrators of homicide [6].…”