The transferable placebo effect from pain to emotion: changes in behavior and EEG activity

Area of Science:

• Neuroscience
• Psychology
• Pain Management

Background:

• Placebo effects are known to alleviate pain perception and reduce negative arousal independently.
• The transferability of placebo effects between different domains, such as pain and emotion, remains largely unexplored.

Purpose of the Study:

• To investigate whether a placebo effect established for pain relief can be transferred to reduce negative affect associated with emotional stimuli.
• To explore the neural mechanisms underlying this transferable placebo effect using electroencephalography (EEG).

Main Methods:

• Participants received a sham analgesic treatment (magnetic equipment) while pain stimulus intensity was secretly reduced.
• Participants then viewed unpleasant pictures to evoke negative affect.
• Electroencephalography (EEG) was used to record brain activity during the emotional task.

Main Results:

• The transferable placebo intervention significantly alleviated participants' negative feelings.
• EEG data revealed decreased P2 amplitude and increased N2 amplitude in response to unpleasant pictures after the placebo treatment.
• Source localization indicated that these EEG changes originated near the posterior cingulate.

Conclusions:

• A placebo effect induced for pain relief can be effectively transferred to modulate emotional responses.
• The findings suggest that the posterior cingulate region plays a role in the neural circuitry of cross-domain placebo effects.
• This research opens new avenues for understanding and potentially harnessing placebo effects in clinical settings for both pain and emotional disorders.