Effects of oxytocin administration and conditioned oxytocin on brain activity: an fMRI study.

Abstract

It has been demonstrated that secretion of several hormones can be classically conditioned, however, the underlying brain responses of such conditioning have never been investigated before. In this study we aimed to investigate how oxytocin administration and classically conditioned oxytocin influence brain responses. In total, 88 females were allocated to one of three groups: oxytocin administration, conditioned oxytocin, or placebo, and underwent an experiment consisting of three acquisition and three evocation days. Participants in the conditioned group received 24 IU of oxytocin together with a conditioned stimulus (CS) during three acquisition days and placebo with the CS on three evocation days. The oxytocin administration group received 24 IU of oxytocin and the placebo group received placebo during all days. On the last evocation day, fMRI scanning was performed for all participants during three tasks previously shown to be affected by oxytocin: presentation of emotional faces, crying baby sounds and heat pain. Region of interest analysis revealed that there was significantly lower activation in the right amygdala and in two clusters in the left superior temporal gyrus in the oxytocin administration group compared to the placebo group in response to observing fearful faces. The activation in the conditioned oxytocin group was in between the other two groups for these significant clusters but did not significantly differ from either group. No group differences were found in the other tasks. The findings carefully suggest that a conditioned response in brain activity was observed, however the conditioned group did not significantly differ from the other groups. Future research should therefore investigate the optimal timing of conditioned endocrine responses and study whether the findings generalize to other hormones as well.

Identifying super-feminine, super-masculine and sex-defining connections in the human braingraph

“…It is striking that just this edge, connecting the Pars Triangularis and the Superior Parietal area in the right hemisphere, has this distinguished ''switching'' property. Other publications also report sex differences in Pars Triangularis and the parietal cortex in context with hormonal regulation (Striepens et al 2014;Hecht et al 2017;Skvortsova et al 2020), speech-language production (Foundas et al 1998;Frederikse et al 1999;Yao et al 2020), in mental rotation performance (Koscik et al 2009). There exist numerous other sets of edges with the superfeminine and supermasculine property; we demonstrated these since they were the smallest set we have found.…”