Amygdala activity contributes to the dissociative effect of cannabis on pain perception
Pain January 1, 2013 Michael C. Lee, M. Ploner, K. Wiech et al.
Delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, reduces the unpleasantness but not the intensity of ongoing pain and hyperalgesia in healthy volunteers. Using functional magnetic resonance imaging, the study found that THC diminished activity in the anterior mid cingulate cortex during hyperalgesia. The reduction in unpleasantness correlated with right amygdala activity, and THC reduced functional connectivity between the amygdala and primary sensorimotor areas during ongoing pain. This dissociation suggests that THC targets the affective qualities of pain through frontal-limbic brain mechanisms, with amygdala activity contributing to individual differences in cannabinoid analgesia.