Description (from grant):    

Chronic pain and opioid over-use are reaching epidemic proportions in the USA, where one in three citizens experiences some degree of pain and over 33,000 opioid related deaths occur annually. This problem results from our lack of understanding the underlying mechanisms of most forms of chronic pain, which has hampered our ability to develop effective treatments. Fibromyalgia (FM) is a common chronic pain condition whose pathology is largely unknown. Existing research suggests that the brain may play a significant role in pain expression in FM, with an imbalance in excitatory and inhibitory brain activity causing an unstable neural network sensitized to external pain stimuli. Explosive synchronization (ES) is a phenomenon wherein small increases in stimulation strength applied to a network can lead to an abrupt state transition through global network synchronization. We hypothesize that ES is an underlying mechanism of the hypersensitive FM brain, and that targeted non-invasive brain stimulation may reduce ES and subsequent pain.  High definition transcranial direct current stimulation (HD-tDCS) is a novel, non-invasive, non-opioid, brain treatment that reduces severity of some types of chronic pain. We will investigate the ability of HD-tDCS to reduce unstable brain network behavior that may drive pain in FM, and likely other chronic pain conditions. In order to monitor the efficacy of the treatment, there is an urgent need for pain biomarkers.