News release

From: Springer Nature

Neuroscience: Brain training may help boost the immune system 

Training people to activate a part of the brain linked to reward and positive expectations may be associated with an increase in the body’s immune response to a vaccine. The findings from a study involving 85 participants, published in Nature Medicine, suggest that positive thinking might help the brain support the immune system in a non-invasive way.

The ventral tegmental area (VTA) is part of the brain’s reward system, which controls motivation and expectation. Animal studies have shown that this system can affect immunity; however, it is unclear whether this same relationship is present in humans. Learning more about this link could provide important insights into the pathways underlying the placebo effect and could lead to new ways to make vaccines more effective.

Nitzan Lubianiker and colleagues developed a novel neuroimaging-based feedback approach to train 85 healthy participants to intentionally increase the activity of their reward mesolimbic pathway (which includes the VTA) as indicated by functional MRI recording. In this approach, a participant chooses mental strategies, such as recalling a previous trip, while mesolimbic pathway activity is simultaneously imaged by functional MRI. Real-time feedback on the effectiveness of the mental strategy is then given to the participant, which allows them to adapt the strategies over multiple training sessions to achieve increased mesolimbic activity. After four training sessions, all participants were given a vaccine against hepatitis B, followed by immunological assessments of blood obtained before and for up to four weeks after injection. The authors found that people who learned to maintain higher VTA activity had a larger increase in levels of protective antibodies in the blood plasma to the vaccine.  The authors also found that in order to maintain high VTA activity, people used mental strategies involving positive expectations — a sign of the placebo effect.

The findings suggest a potential link between the activity of specific brain pathways and the immune system that could be useful for identifying targets associated with the placebo effect in humans and future treatments. However, the study only measured antibody levels and was not designed to test the clinical efficacy of the vaccine. Furthermore, the increased antibody levels seen in the study were associated only with VTA activity and were not significantly different across the neurofeedback groups. Larger trials and further research are needed to determine whether focusing on positive expectations and VTA activity could reliably improve immune health.