How does the midbrain contribute to pain?

Pain functions to guide our interactions with the world; it is at its core motivational - to coordinate both short- and long-term behaviour in order to minimise harm. Potentially harmful stimuli are detected by nociceptive sensory neurons in the skin that evoke immediate behaviours (withdrawal, orientation, etc.) and pain. It is paramount that these responses are precise, appropriate, and perhaps most critically, rapid, in order to drive protective activity within a few hundred milliseconds. The development of state-of-the-art methods, such as in vivo optogenetics, neural probes, high-speed videography, and computer vision, has allowed mapping of these diverse and dynamic sub-second protective behavioural responses. This can provide an unprecedented view of stimulus response relations in the somatosensory system. These methods will be used to determine how the midbrain guides sub-second protective responses and the experience of pain in adaptive and maladaptive states. Chronic pain affects more than 1.5 billion people worldwide and has a large impact on the quality of life of individuals and on our society as a whole.