How the Brain Controls Pain

Why do we have pain? And why is there not a simple, direct link between bodily injury and pain? Acute pain is a valuable warning signal, with both a “sensory” component and a strong “suffering” component that motivates us to withdraw from possible injury and to avoid that situation in the future. However, there are times when pain cannot be the highest priority: for example, you cannot stop to nurse a twisted ankle when running away from a hungry bear! This modulation of pain based on other priorities and needs is mediated by a defined “pain-modulating system” in the brain, which can either suppress or promote pain by inhibiting or facilitating transmission of the pain “signal” from the injured tissue to the brain. We now know that there are distinct populations of neurons in the that inhibit pain (referred to as “OFF-cells”) and enhance pain (termed “ON-cells”). In her presentation, Dr. Heinricher will describe how these neurons were defined, and how OFF-cells mediate the analgesic actions of opioid drugs and of intense stress. Dr. Heinricher will also talk about the contribution of brain ON-cells to chronic pain. Chronic pain does not have obvious value as a warning signal, and unlike acute pain, is extremely difficult to treat. Dr. Heinricher will describe how plasticity in the pain-modulating circuit contributes to chronic pain, and discuss how cognitive and emotional factors, including mild stress, activate ON-cells and make our pain worse.

If you prefer to attend this lecture in presence, you should write to segreteria.isa@unibo.it within September 28th, 12 p.m. and book your place. The places will be assigned on “first come first served” basis.

As per the Decree-Law number 111, issued on the 6th of August 2021, in order to attend lectures in presence you must have a COVID-19 Green Pass and show it on the premises.

Prof. Heinricher holds joint faculty appointments in the Departments of Neurological Surgery, Behavioral Neuroscience, and Physiology &Pharmacology at Oregon Health & Science University. She is also Associate Dean for Research in the School of Medicine, and Vice Chair for Research in Department of Neurological Surgery, School of Medicine. Prof. Heinricher’s work focuses on the physiological and pharmacological properties of brainstem neurons that modulate pain by enhancing or suppressing transmission of nociceptive information from the spinal cord up to the brain. Using a combination of electrophysiology, behavioral testing, and pharmacological and optogenetic/chemogenetic manipulation, her group showed that the neural basis for bi-directional control of pain from the brainstem derives from two physiologically and pharmacologically distinct classes of neurons: "OFF-cells," which exert a net inhibitory effect on nociception, and “ON-cells", which have a facilitating action. Her laboratory is now considering how these pain-modulating systems are engaged by higher centers, and how they are brought into play under physiological and pathophysiological conditions, e.g., during stress or in migraine headache. She is also interested in how pain modulation is coordinated with other adaptive behavioral and physiological responses in order to match pain sensitivity to other priorities. Her work provides insights into the roles of positive feedback and top-down control mechanisms in clinically significant pain, including migraine headache, as well as into mechanisms of analgesic drug action.

The visit of Mary Heinricher is organized in collaboration with Domenico Tupone from the Department of Biomedical and Neuromotor Sciences.