Have you ever noticed that looking at pictures of good times with family or friends lessens your headache pain? Longing has already been shown to be helpful in relieving pain, and a new study has now revealed the thalamocortical mechanism of longing-induced analgesia.
Led by Dr. KONG Yazhuo from the Institute of Psychology, Chinese Academy of Sciences, the research team found that the thalamus, a brain region critical for pain modulation, is also linked to the analgesic effect. associated with nostalgia.
Nostalgia, a sentimental longing for one’s past, is a conscious social emotion, perhaps bittersweet but mostly positive. Nostalgia helps us maintain a positive psychological state by neutralizing the negative impact of difficult situations. The adaptive functions of longing are numerous, one effect being pain relief.
In the present study, a functional MRI paradigm related to nostalgia (i.e., nostalgia over control cues when people viewed images) was combined with heat-pain stimulation (c that is, low heat versus high heat when people felt pain) to examine how brain responses elicited by pain stimulation were modulated after people experienced a nostalgic emotion.
After observing childhood memory triggers, participants reported feeling weaker pain sensations in response to thermal stimuli, particularly at low stimulus intensities.
More importantly, the anterior thalamus encoded longing and the posterior parietal thalamus encoded pain perception. Anterior thalamic activation can predict posterior parietal thalamus activation. “The thalamus plays a key role as a central functional link in the analgesic effect,” said Dr. ZHANG Ming, first author of the study.
When people viewed images, the strength of nostalgia felt was also strongly associated with the connectivity between the thalamus and the periaqueductal gray (PAG), an area of gray matter located in the midbrain. In this situation, the coupling between the PAG and the dorsolateral prefrontal cortex predicted pain perception when people felt pain. This indicates that the thalamus modulates nociceptive inputs and plays a crucial role in triggering the brainstem analgesic pathway.
Sometimes people experience mild clinical pain that is uncomfortable, but not enough to require medication. In these cases, non-drug analgesic pain relief methods may be helpful or even necessary.
This study sheds light on the neural mechanisms underlying nostalgia-induced pain relief, providing new insights into the development and improvement of non-drug psychological analgesia.
Reference: “Thalamocortical mechanisms for nostalgia-induced analgesia” February 28, 2022, J Neurosci.
This work was published in the Journal of Neuroscience on February 28 and was funded by the National Natural Science Foundation of China and the National Social Science Fund of China.