What role does the cerebellum play in placebo and nocebo effects?

The latest research findings are showing, with increasing clarity, that the role of the cerebellum goes far beyond motor control and motor learning. In fact, this part of the brain is involved in many cognitive, emotional, and behavioural functions. It might even act as a kind of neuronal ‘prediction machine’ that predicts, for example, the physical sensation of touch and corrects this assumption if the expectation is not confirmed. Given that such expectations and learning processes also contribute significantly to placebo and nocebo effects, it stands to reason that the cerebellum might also play a significant role in these processes.

Which areas of the cerebellum are involved in placebo effects?

In Project A17, we are investigating this link between the cerebellum and placebo and nocebo effects using the example of pain. A general involvement of the cerebellum in the development and control of pain is already well documented. There are also initial indications that the cerebellum contributes to pain relief through placebo effects, as this so-called placebo hypoalgesia appears to be reduced in patients with damage to the cerebellum. However, so far, data on this phenomenon are limited, and it remains unknown which areas of the cerebellum are responsible and how they interact with other areas of the brain.

In-depth insights thanks to fMRI and EEG

Within Project A17, we are therefore investigating whether damage to the cerebellum indeed reduces placebo effects and whether this also applies to nocebo effects. We will then use magnetic resonance imaging (MRI) to identify which areas of the cerebellum are involved in placebo and nocebo effects. In further studies, we will additionally use functional MRI (fMRI) and electroencephalography (EEG) to investigate which other brain regions the cerebellum interacts with and to explore the relationship between treatment expectation effects and the predictive function of the cerebellum.