Differences in brain circuitry for appetitive and reactive aggression as revealed by realistic auditory scripts.

James K Moran,Thomas Elbert,Roland Weierstall

doi:10.3389/fnbeh.2014.00425

James K Moran, Thomas Elbert + Show 1 more

Open Access

https://doi.org/10.3389/fnbeh.2014.00425

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Abstract

Aggressive behavior is thought to divide into two motivational elements: The first being a self-defensively motivated aggression against threat and a second, hedonically motivated “appetitive” aggression. Appetitive aggression is the less understood of the two, often only researched within abnormal psychology. Our approach is to understand it as a universal and adaptive response, and examine the functional neural activity of ordinary men (N = 50) presented with an imaginative listening task involving a murderer describing a kill. We manipulated motivational context in a between-subjects design to evoke appetitive or reactive aggression, against a neutral control, measuring activity with Magnetoencephalography (MEG). Results show differences in left frontal regions in delta (2–5 Hz) and alpha band (8–12 Hz) for aggressive conditions and right parietal delta activity differentiating appetitive and reactive aggression. These results validate the distinction of reward-driven appetitive aggression from reactive aggression in ordinary populations at the level of functional neural brain circuitry.

Highlights

Aggression has long been regarded as a dichotomous phenomenon (Weinshenker and Siegel, 2002; Mcellistrem, 2004; Meloy, 2006), belonging to two different motivational systems: One representing self-defense with the avoidance of threat and danger, and the other broadly representing the planning and execution of proactive attacks.Reactive aggression is relatively well defined both behaviorally and in neurobiological terms as a functional response to threat
Animal studies suggest that the underlying neural circuitry of reactive aggression is largely the same in predators and prey: The activity in the medial amygdala, the hypothalamic attack area, and the periaqueductal gray axis, determines aggressive behavior in animals
The orbitofrontal cortex (OFC) plays a role in evaluating rewards vs. expectations of rewards, and as such is associated with frustration (Blair, 2004), as well as recognizing violations of social norms (Blair and Cipolotti, 2000), both of which can be a trigger for reactive aggression

Summary

INTRODUCTION

Aggression has long been regarded as a dichotomous phenomenon (Weinshenker and Siegel, 2002; Mcellistrem, 2004; Meloy, 2006), belonging to two different motivational systems: One representing self-defense with the avoidance of threat and danger, and the other broadly representing the planning and execution of proactive attacks. Earlier studies have used imagination scenarios to successfully activate aggression related areas (Pietrini et al, 2000), our experiment has the additional advantage of presenting a realistic and complex stimulus to each group which is perceptually identical, whilst at the same time separating reactive from appetitive aggressive responses This use of complex real-world stimuli has become more popular with the advance of a variety of different analytical techniques (Hasson et al, 2004; Wilson et al, 2008), and provides us with the opportunity to improve the comparability between field and laboratory research for validating phenomena identified in a natural context. We predict a differential oscillatory activity between reactive and appetitive and control conditions, since this is exploratory, we examine activity from low to high frequency bands across the whole brain

MATERIALS AND METHODS

RESULTS

DISCUSSION