Using cannabis for pain relief does help, however, it makes pain more bearable rather than getting rid of it, researchers from Oxford University's Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB) reported in the journal Pain. According to MRI brain imaging scans in this latest study, areas of the brain that interpret pain were not affected significantly when people took THC. It appears that cannabis affects people's emotional state in a way that makes pain less awful.
The participants' reports regarding how unpleasant their pain was were backed up by MRI scan results. An area in the bran called the anterior mid-cingulate cortex, which has many functions, including the emotional aspects of pain, became less active after participants took THC. The scans also showed that activity changed in the right amygdala, which correlated with the reduction in the unpleasantness of the pain after people had taken THC. Experts already know that pain can "prime" the right side of the amygdala."