Poster A55, Tuesday, August 20, 2019, 10:15 am – 12:00 pm, Restaurant Hall
Oxytocinergic Modulation of Speech Production
Charlotte Vogt1, Mareike Floegel1, Suzanna Gispert-Sanchez2, Christian A. Kell1;1Brain Imaging Center and Department of Neurology Goethe University Frankfurt, 2Molecular Neurogenetics, Goethe University Frankfurt
Speech is a means of human social communication. It has been proposed that many socio-affective behaviors, such as speech, are modulated by the neuropeptide oxytocin (Heinrich et al., 2009). While oxytocin is known to modulate speech perception (Tops et al., 2011), it is not known whether it also modulates speech production. There are different approaches of investigating the physiological role of oxytocin. One consists in the nasal administration of the neuropeptide. Another approach is to investigate the effect of functional polymorphisms in the oxytocin receptor gene. Here we investigated drug*polymorphism interactions in a double-blind within-subject design. We performed a cue-target fMRI reading paradigm in 50 healthy, male participants. In two overt reading conditions participants read a sentence with either neutral or happy intonation, a covert reading condition served as a common baseline. Participants were studied once under the influence of intranasal oxytocin and in another session when they received placebo (randomized order). For group analyses, participants were divided into two groups, AA/AG and GG, based on their rs53576 oxytocin receptor polymorphism (Riem et al., 2011). In carriers of the A allele, the oxytocin receptor is thought to be less effective compared to GG homozygotes (Tops et al., 2011). Neither administration of oxytocin or placebo, nor receptor genotypes affected intensity contours or fundamental frequencies of participants’ utterances significantly. However, there were drug*polymorphism interactions in speaking-related brain activity, independent whether prosody was neutral of happy. Under placebo, carriers of the A allele showed decreased activation when preparing to speak in the pre-supplementary motor area and cingulate motor area in comparison to GG homozygotes. The administration of oxytocin increased activation in this preparatory set of regions in carriers of the A allele. In this group, oxytocin administration decreased speaking-related activation in auditory feedback processing regions and primary somatosensory cortex compared to placebo. Administration of oxytocin had a less prominent effect on speaking-related brain activity in GG homozygotes. Our results suggest that oxytocin assists in preparatory processes for speech production. Gating of preparatory processes in people with less efficient oxytocinergic modulation through oxytocin administration reduces the need of speech feedback monitoring. This suggests oxytocin facilitates feedback control of verbal communication, which assures that what was planned to be said actually was conveyed. Such a control is essential in social communication.
Themes: Language Production, Language Genetics
Method: Functional Imaging