Psilocybin reduces threat-induced modulation of amygdala connectivity

Researchers from Psychiatric Hospital, University of Zurich, led by Rainer Kraehenmann found that psilocybin substantially reduced the modulatory effect of threat on the top-down connection from the amygdala to the primary visual cortex in normal human subjects. These findings may have important implications for the treatment of mood and anxiety disorders as well as inhibiting the fear-responses during exposure-based psychotherapy, which may facilitate therapeutic progress during the treatment of post-traumatic stress disorder.

The August 2015 article from NeuroImage: Clinical titled 'The mixed serotonin receptor agonist psilocybin reduces threat-induced modulation of amygdala connectivity' (PDF) stems from previous research (2014) from the journal Biological Psychiatry titled 'Psilocybin-Induced Decrease in Amygdala Reactivity Correlates with Enhanced Positive Mood in Healthy Volunteers' (PDF) (Cited by - Google Scholar). The 2014 research demonstrated that "acute treatment with psilocybin decreased amygdala reactivity during emotion processing and that this was associated with an increase of positive mood in healthy volunteers. These findings may be relevant to the normalization of amygdala hyperactivity and negative mood states in patients with major depression." It should be noted that amygdala hyperactivity plays a role in PTSD pathology and the amygdala abundantly expresses 5-HT2a receptors.