CORTEX conference by Christian Büchel

This presentation will focus on the neurobiological mechanisms of pain perception investigated in humans using functional magnetic resonance imaging (fMRI). After reviewing early studies on basic pain properties, the talk will focus on novel insights in learning mechanisms of pain and novel imaging techniques which allow the visualizing of pain processing at the level of the spinal cord in humans. In addition, the presentation will cover the neuronal mechanisms of how expectation can shape pain perception. This will be illustrated through experiments on placebo analgesia, a prominent example of how cognition can modulate pain perception. As placebo analgesia has been shown to be mediated by endorphins, a study using the opioid antagonist (naloxone) will also be presented. Using high resolution fMRI of the human spinal cord could further show that decreased pain responses under placebo were paralleled by strongly reduced pain-related activity in the spinal cord under placebo, providing direct evidence for spinal inhibition as one mechanism of placebo analgesia. The converse, namely increased activation in the opposite direction (i.e. nocebo effect) will also be presented. Finally, the talk will end with presenting a recently published new imaging method that is capable of assessing the brain and the spinal cord at the same time. This, for the first time, allows to assess interregional coupling between brain and spinal cord which will be helpful in studying how cognition can affect pain perception, but will also help to unravel the mechanisms of chronic pain.