Semantic emotional processing (N400) in violent individuals from a community sample

Abstract

Background

Several studies have suggested different brain abnormalities and cognitive impairment in violent individuals, all of them associated with brain areas like the prefrontal and temporal cortex and limbic regions involving executive functions, decision making, language and emotional regulation. However, most studies have focused on EEG quantitative analysis or other components like the P300; additionally, the majority have been performed on forensic samples.

Objective

To explore semantic/emotional processing using an N400 paradigm in a general population sample.

Material and methods

60 adult males were recruited and divided into two groups: control group (healthy men from the general population; n = 30), violent group (violent men from the general population; n = 30). All subjects were assessed with an aggression questionnaire (RPQ; Raine et al.¹⁷) to be classified into one of the groups. Repeated-measures [Group (violent, control) × condition (congruent, incongruent)] ANOVA was used. Separate analyses were performed on the peak amplitude of the N400 difference wave and the original peaks from the incongruent and congruent conditions.

Results

We found no significant differences in behavioral responses. However we found that the control group elicited different activity for each condition (congruent and incongruent); the violent group did not. We found significant differences in the N400 difference wave in medial and lateral lines between the groups. There were differences in the congruent condition in all the lines between groups; there were no differences in the incongruent wave between groups. In the brain mapping we observed that the control group elicited negative activity during the incongruent condition and positive activity during the congruent; meanwhile the violent group elicited similar activity in both conditions.

Conclusions

Semantic emotional processing is impaired in violent individuals, suggesting deficient processing in the integration of language elements in an emotional context. The biological risk of violence in these individuals is disputed.