Discovering mechanisms of pro-nociception: The role of spinal and supraspinal structures

点击翻译按钮获取中文摘要

Although it is unpleasant, pain is crucial for all animals. Pain is a warning signal, to protect normal tissue from damage, and damaged tissue from further harm. The human experience of pain is incredibly variable: people respond differently to the same painful stimulus. While there are multiple reasons for this, recent evidence suggests that different people may actually be wired differently; that is, there are differences in how pain information is transmitted and encoded in the nervous system. The long-term goal of my research is to identify differences in pain processing.***The focus of our current research is how the experience of pain changes over time. When a painful stimulus (e.g., a hot probe) is applied for a long time, the perception of pain fluctuates, even if the temperature of the probe remains the same. This feature of pain is called modulation, and is due, in part, to processing that occurs in the nervous system. Modulation can either amplify (turn up) or inhibit (turn down) pain. My laboratory is working to identify which circuits in the brain and spinal cord modulate pain, and how.******We perform two types of experiments in human subjects. In one test, a hot (45°C) probe is applied to the hand. The subject is given a controller, and adjusts probe temperature so that the sensation of the probe remains constant. If the subject turns the temperature up, this indicates that inhibitory modulation is occurring; probe temperature hasn't changed, but the nervous system reports that the probe is getting cooler (or less painful). Conversely, if the subject turns the temperature down, the nervous system is amplifying the incoming, painful signal. ******In another test, we apply the same hot probe, and measure concentrations of neurotransmitters – chemicals that allow nerve cells to communicate – in the brain and spinal cord. We will use a cutting-edge technique (MRS): this technique allows us to measure the concentration of chemicals inside the body safely and non-invasively, without removing fluid from the nervous system.******The field of pain research is limited by relying on tests that require subjects to rate their pain. In contrast, the tests described here provide objective information about pain processing. Identifying circuits that control our perception of pain is the crucial first step to understanding why two seemingly similar people respond so differently to a painful stimulus. **