Psilocybin-induced decrease in amygdala-putamen coupling during an event-related face discrimination task O. Grimm1, R. Krähenmann2, K. Preller2, E. Seifritz2, F. Vollenweider2. 1University Hospital Frankfurt, Departement of Psychiatry, Psychosomatics and Psychotherapy, Frankfurt am Main, Germany. 2Psychiatric Hospital Zurich, Department of Psychiatry- Psychotherapy and Psychosomatics, Zürich, Switzerland.

Introduction Results Psilocybin is a famous hallucinogen with fascina- Face discrimination Psilocybin Placebo Stats was slower in the HIT rate 63.16 % 64.44 % p=0.59 ting pharmacological pro- angry SD 1.5 SD 1.7 perties which might be explo- psilocybin condi- HIT rate 68.1 % SD 68.8 % SD p=0.66 tion. This effect was fearful 1.2 1.2 red for clinical application. HIT rate 65.55 % 64.61 % p=0.73 not face emotion happy SD 2.02 SD 1.88 modality specific. MEAN 9268 SD 7998 SD p=0.004 It modulates the amygdala activity via its Correct face clas- RT angry 262 308 5HT1A/2A agonistic properties. Therefore, MEAN 8985 SD 7552 SD p=0.006 sification was not emotional face processing is an ideal paradigm RT fearful 400 279 significantly distur- MEAN 9150 SD 7734 SD p=0.006 for studying it’s effects. RT happy 361 321 Amygdalabed. seed connectivity In this study, we investigated psilocybin’s effects on amygdala connectivity during an During the angry event-related face discrimination task in n=18 faces condition, the healthy volunteers who received psilocybin and connectivity with placebo in a cross-over design. Face the left caudate and discrimination of emotional faces relies on both putamen was prefrontal as well as subcortical structures, decreased ( cluster- namely the amygdala. We hypothesized that the corrected pFDR < amygdala activity alone or as part of a network 0.23, threshold p < is altered during psilocybin application. This 0.001, whole brain could manifest in altered salience of emotional corrected ). face-processing in task activity or in task- related connectivity of the amygdala.

Materials and methods Conclusions In conclusion, psilocybin randomized, double-blind, placebo-controlled, Psilocybin alters the seems to be a mixed cross-over design, subjects received either reaction to emotional serotonin-agonist which placebo or 0.16 mg/kg oralpsilocybin in two stimuli. The effect is a selectively modulates separate imaging sessions at least 14 days general slowing of emo- relevance and saliency of apart tional face discrimination. Only in angry faces, a the external stimuli by Beta series correlation effect of amygdala-pu- altering central hubs of the limbic system. Therefore, We modelled each face-trial a separate tamen connectivity was psilocybin as both po- regressor to obtain trial-to-trial variations and found. tential as a tool or probe assess to correlations between Amygdala-ROIs and as a therapeutic agent. within subject and then across subjects

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References Kraehenmann R, Preller KH, Scheidegger M, et al. Psilocybin-Induced Decrease in 4 Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers. Biol Psychiatry. 2014:1-9. doi:10.1016/j.biopsych.2014.04.010. Vollenweider FX, Kometer M. The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nat Rev Neurosci. 2010;11(9):642-651. doi:10.1038/nrn2884.

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We declare that there is no conflict of interest