Effects of parental verbal abuse experience on the Glutamate response to swear words in the ventromedial prefrontal cortex: A functional H1-magnetic resonance spectroscopy study

Several lines of evidence indicate verbal abuse (VA) critically impacts the developing brain; however, whether VA results in changes in brain neurochemistry has not been established in humans. Here, we hypothesized that exposure to recurrent parental VA elicits heightened glutamate (Glu) responses during the presentation of swear words, which can be measured with functional magnetic resonance spectroscopy (fMRS). During an emotional Stroop task consisting of blocks of color and swear words, metabolite concentration changes were measured in the ventromedial prefrontal cortex (vmPFC) and the left amygdalohippocampal region (AMHC) of healthy adults (14 F/27 M, 23{+/-}4 years old) using fMRS. The dynamic changes in Glu and their associations with the emotional state of the participants were finally evaluated based on 36 datasets from the vmPFC and 30 from the AMHC. A repeated-measures analysis of covariance revealed a modest effect of parental VA severity on Glu changes in the vmPFC. Furthermore, the total score on the Verbal Abuse Questionnaire by parents (pVAQ) was associated with the Glu response to swear words ({Delta}GluSw e). The interaction term of {Delta}GluSw e and baseline N-acetyl aspartate (NAA) level in the vmPFC could be used to predict state-trait anxiety level and depressive mood. We could not find any significant associations between {Delta}GluSw e in the AMHC and either pVAQ or emotional states. We conclude that parental VA exposure in individuals is associated with a greater Glu response towards VA-related stimuli in the vmPFC and that the accompanying low NAA level may be associated with anxiety level or depressive mood.