​More brain research?

Anyone delving deeper into the world of chronic pain research will have noticed a wide array of theories and studies on the brain [1]. On one hand, functional neuroimaging research looks at the activity of certain areas of the brain or what areas seem to be ‘talking’ to each other. On the other hand, structural neuroimaging studies highlight which brain regions look different or what regions are connected with each other [2]. However, researchers still do not quite understand how these altered brain regions interact with each other and what this has to do with chronic pain. Furthermore, structural and functional studies are rarely integrated. While functional data gives us information about active networks, it does not guarantee strong physical connections within this network. On the opposite hand, structural studies provide us with an anatomical framework for the network but does not guarantee the active use of all connections. So, even though there is plenty of brain research, there is still a lot of work to be done!

Getting to work to connect the dots

In the project of my team’s and mine, we aim to construct a neural connectome for three groups differing in pain extent: fibromyalgia (widespread pain), chronic low back pain (localized pain) and pain-free controls. We are constructing these connectomes based on predefined regions of interest, based on the extensive literature mentioned above. Specifically, we are looking at areas of the brain involved in sensations or what we would call ‘nociception’ (e.g. primary and secondary sensorimotor cortices), areas of the brain involved in the emotional aspects of pain or what we would call the ‘limbic areas’ (e.g. thalamus, amygdala & hippocampus) and other areas that have previously been identified in chronic primary pain populations (e.g. prefrontal cortex & orbitofrontal cortex). To create these connectomes, we are using both functional and structural MRI scans: a type of neuroimaging that employs a powerful magnet to study properties of the brain in a non-invasive way. Each of these two methods generates its own connectivity matrix, so that we can mathematically average them to end up with a connectome that contains both functional and structural information. Once we have this connectome, we can calculate all types of interesting outcomes: how efficiently information travels across this entire network, how important each area is within this network, if there are important sub-networks and so on. Finally, to give these findings a clear meaning, we will see if they are related to experimental pain outcomes. For example, is the efficiency of the limbic sub-network related to the ability to efficiently modulate your pain? Is the increased importance of the primary sensorimotor cortex related to a decrease in pain threshold? In my PhD project, we are specifically interested in the role of stress in chronic pain. For that reason, we also believe that it could be really valuable to see if these neural connectome alterations are associated with specific stress system characteristics, such as increased cortisol levels or lower blood pressure.

So… What now?

My team and I are currently fine-tuning this methodological plan, but initial results already seem interesting. However, we are still currently collecting some final data! Specifically, we are looking for some last participants that have a fibromyalgia diagnosis or that are currently pain-free. In this study, we comprehensively map a participant’s stress system, their experimental pain outcomes and of course we also perform some extensive neuroimaging. Want to help with this innovate project? E-mail us at strain@ugent.be