03: Placebo Effect Change the Brain?

Doctor: "I'm prescribing this, it will help reduce the pain."

https://www.vox.com/science-and-health/2017/7/7/15792188/placebo-effect-explained (This Vox article is a great source for a pretty wide ranging review of the placebo effect)

What is it?

A placebo is something that has no innate ability to alter cognition, however the belief of the placebo's power can alter cognitions. Placebos can come in the form of: pills (e.g. sugar), injections (e.g. saline), drugs (e.g. oregano or non-alcoholic beer), and many other treatments/techniques.

 

History:

The term "placebo" in medical jargon likely arose around 1770 (Jütte, 2013), despite the fact practitioners were harnessing the placebo effect long before. For example, the German practitioner: Franz Anton Mesmer effectively reduced anxiety/hysteria/bodily ailments with magnets.

Brain Changes From Placebo:

Researchers have found neurological changes involved with the placebo effect especially in the management of pain, but what specific parts of the brain?

 

Recent Research:

Recent research from Zunhammer and Colleagues (2021) looked at pain response to a placebo via functional magnetic resonance imaging (fMRI) which measures changes in brain activity via the blood's oxygen level. The researchers wanted to determine:

 

Results:

Following figure shows area of brain most influenced by the reduction in pain caused by placebo effect.

 

1) Which area of the brain appear to have a reduction of activity (blue) during placebo effect?

Answer: There are multiple areas involved with the placebo effect, but the somatosenory area (SMA) and thalamus are easiest to view.

 

 

2) Describe the following (voxel = tiny 3D area of measured brain matter):

  

Answer: areas that are darker blue experienced a larger decrease in neural activity and that decrease in neural activity was correlated to a reduction in pain.

 

3. What does the following mean: 

Answer:  As stated in the figure, the SMA and thalamus are negatively related to the placebo effect: as neurological area decreases in activity, placebo effect increases. In addition: insula, 2ndary SMA, etc... also negatively correlated to placebo effect.

4. In conclusion:

Researchers found evidence that multiple brain areas (including parts of the frontal cortex) are involved with the placebo effect.

Sources:

Jütte, R. (2013). The early history of the placebo. Complementary Therapies in 

    Medicine, 21, 97-97. https://pubmed.ncbi.nlm.nih.gov/23497809/

Zunhammer, M., Spisák, T, Wager, T., D., & Bingel, U., (2021). Meta-analysis of 

    neural systems underlying placebo analgesia from individual participant fMRI 

    data. Nature Communications, 12. 10.1038/s41467-021-21179-3