Neuromodulation of cursing in American English: A combined tDCS and pupillometry study

Abstract

Many neurological disorders are associated with excessive and/or uncontrolled cursing. The right prefrontal cortex has long been implicated in a diverse range of cognitive processes that underlie the propensity for cursing, including non-propositional language representation, emotion regulation, theory of mind, and affective arousal. Neurogenic cursing often poses significant negative social consequences, and there is no known behavioral intervention for this communicative disorder. We examined whether right vs. left lateralized prefrontal neurostimultion via tDCS could modulate taboo word production in neurotypical adults. We employed a pre/post design with a bilateral frontal electrode montage. Half the participants received left anodal and right cathodal stimulation; the remainder received the opposite polarity stimulation at the same anatomical loci. We employed physiological (pupillometry) and behavioral (reaction time) dependent measures as participants read aloud taboo and non-taboo words. Pupillary responses demonstrated a crossover reaction, suggestive of modulation of phasic arousal during cursing. Participants in the right anodal condition showed elevated pupil responses for taboo words post stimulation. In contrast, participants in the right cathodal condition showed relative dampening of pupil responses for taboo words post stimulation. We observed no effects of stimulation on response times. We interpret these findings as supporting modulation of right hemisphere affective arousal that disproportionately impacts taboo word processing. We discuss alternate accounts of the data and future applications to neurological disorders.