In our latest study on deep brain stimulation we have found that deep brain stimulation (DBS) has large wide spread effects on the whole brain. It has long been thought that DBS relies on the specific structure of the stimulated tissue as well as the connectivity pattern from a brain area. This might indeed still be true and both necessary as well as sufficient for successful symptom alleviation. However this new study also shows a large spread of functional changes across the whole brain. It is conceivable that these changes contribute to any changes seen in non-motor symptoms.
In this recent study we have looked at the effects of DBS on brain function and brain dynamics. We have used a truly unique opportunity to acquire MRI scans of patients with Parkinson’s disease who receive DBS treatment *. The results clearly show wide spread effects of DBS when turning stimulation ON compared to OFF. Furthermore, the brain dynamics when stimulation is turned ON approach the brain dynamics found in healthy controls. This is even found in areas not directly connected (structurally) to the brain area where the DBS electrodes are implanted, as can be seen in the figure below. The areas identified here are very similar to those areas found to show structural changes over time observed after long-term DBS in Parkinson’s disease.
This study sheds new light on how DBS works and to what extend very local stimulation can affect whole brain dynamics through a sparsely connected underlying structural network. By adding this new evidence to the overall knowledge on DBS and how it works, we get again one step closer to created a complete and full picture. This of course will at some point provide us with enough information to improve current procedures (e.g. brain areas to target). It may also allow for the use of DBS in disorders that are as of yet difficult or even impossible to treat. Obviously we still need a lot more information, but combining the evidence we have with computational modelling would allow us to simulate and predict possible outcomes of treating disorders with DBS without the use of animals or people until the desired outcome is reached.
* It should be stated here that putting patients with DBS in an MRI scanner is only safe when following strict protocols to avoid any chance of adverse events. For this study all protocols and evidence from previously published studies have been implemented.