Serotonergic contributions to human brain aggression networks

Martin Klasen, Dhana Wolf, Patrick D. Eisner, Thomas Eggermann, Klaus Zerres, Florian D. Zepf, René Weber, Klaus Mathiak

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Aggressive behavior is associated with dysfunctional frontolimbic emotion regulation circuits. Recent findings suggest serotonin as a primary transmitter for prefrontal amygdala control. However, the association between serotonin levels, amygdala regulation, and aggression is still a matter of debate. Neurobehavioral models furthermore suggest a possible mediating influence of the monoamine oxidase A gene (MAOA) on this brain-behavior relationship, with carriers of low expressing allele varieties being a risk group for aggression. In the present study, we investigated the influence of brain serotonin modulation and MAOA genotype on functional amygdala connectivity during aggressive behavior. Modulation of serotonergic neurotransmission with acute tryptophan depletion (ATD) and placebo were administered in a double-blind, cross-over design in 38 healthy male participants. Aggressive behavior was modeled in a violent video game during simultaneous assessment of brain activation with functional magnetic resonance imaging (fMRI). Trait aggression was measured with the Buss-Perry Aggression Questionnaire (BP-AQ), and MAOA genotypes were assessed from blood samples. Voxel-wise functional connectivity with anatomically defined amygdala was calculated from the functional data. Tryptophan depletion with ATD reduced aggression-specific amygdala connectivity with bilateral supramarginal gyrus. Moreover, ATD impact was associated with trait aggression and MAOA genotype in prefrontal cortex regions. In summary, serotonergic corticolimbic projections contribute to aggressive behavior. Genotype-specific vulnerability of frontolimbic projections may underlie the elevated risk in low expressing allele carriers.

Original languageEnglish
Article number42
JournalFrontiers in Neuroscience
Issue numberFEB
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© 2019 Klasen, Wolf, Eisner, Eggermann, Zerres, Zepf, Weber and Mathiak. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.


  • Aggression
  • Amygdala
  • PFC
  • Serotonin
  • Supramarginal gyrus
  • Tryptophan depletion


Dive into the research topics of 'Serotonergic contributions to human brain aggression networks'. Together they form a unique fingerprint.

Cite this