About this Research Topic
Pain is a multidimensional experience, and the negative affect, or how much the pain is ‘bothersome’, significantly impacts the quality of life of the sufferer. In fact, this emotional component of pain has been argued to be the most important metric predicting quality of life. There is extensive interaction between systems involved in pain processing and other affective and motivational systems. Notably, it is common for chronic pain to be comorbid with mood disorders (e.g. depression), where we have proposed that dysfunction of mesolimbic circuitry (including dopamine neurotransmission) precipitates mood disorders and impairs motivated behavior. Our understanding of how pain modulates mesocorticolimbic reward circuitry and the dopamine system has evolved tremendously in the past decade. While rewarding stimuli stimulate the dopamine system, dopamine release does not always correlate with reward onset and aversive stimuli can also activate this system, challenging the dogma that dopamine equates with pleasure or reward. Mesolimbic dopamine is now considered as a salience signal that drives motivated behavior, and consequently, theories have now been revised to understand how this system contributes to acute and chronic pain conditions. The endogenous opioid system is also involved in regulating states of motivation and emotion, and accumulating evidence indicates that changes in opioid function may lead to the genesis of affective like disorders in chronic pain states via disregulation of reward circuitry. Finally, stress (which commonly accompanies on-going pain) also significantly modulates reward circuitry and has been implicated in prescription analgesic addiction and drug relapse.
Articles will be solicited to provide evidence for how chronic pain changes reward circuitry, its interactions with the stress system, and the implications this has for the genesis of psychiatric disorders such as depression and addiction. Research papers will also address central questions regarding how aversive salient cues, such as pain, engage the reward circuitry system, and how this affects behavior. Finally, the implications for motivated behavior, reward learning, and opioid addiction in the context of acute and chronic pain will be included. Both clinical and basic science papers will be requested in the form of reviews, original papers and case reports.
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