Abstract
The rapid evaluation of low-level perceptual features of a face has high ecological value, allowing rapid detection of emotion and threat. The level of vigilance is enhanced in those with social anxiety and high autistic tendencies. The existence of a direct, low spatial frequency, subcortical route to the amygdala, via the pulvinar, has been postulated. Oxytocin (OXT) has shown potential benefit for Social Anxiety Disorder as well as for autism, through regularisation of amygdala activity. OXT research has largely focused on neuroimaging of the social brain, with relatively few studies of the interaction of OXT and visual sensory processing. Using a cross-over double-blind placebo-controlled design with 27 neurotypical young adult males, we tested the psychophysical and electrophysiological effects of nasally administered OXT and placebo. EEG recordings over occipital and parietal cortex were taken during the visual recognition tasks. In addition, multifocal visual evoked potentials were recorded so that any variation in afferent magnocellular and parvocellular activity could be measured. Using paired t-tests, significant differences were observed in several of the facial emotion evoked responses comparing OXT and placebo administration. For the P100 peak with fearful faces, mean amplitude was reduced under OXT cf Placebo for left hemisphere electrodes (P7, PO7), and increased for Happy face stimuli. No differences were recorded for Neutral faces, nor for N170 peaks. Also right hemisphere (P8, PO8) recordings were not different. The multifocal VEP showed an OXT cf Placebo latency advance in the grand mean average waves for the early (N70) peaks of the first order kernel and the first slice of the second order kernel (K2.1), responses that have been previously been linked to magnocellular function. It appears that intranasal OXT is projecting effects of emotional visual processing onto visual parietal and occipital cortex. This situation could reflect modulation of an amygdala-pulvinar-MT/V5 interaction.
Meeting abstract presented at VSS 2018