Looking at photos of good times with family or friends provokes nostalgia, an emotion that, although bittersweet, is also positive. Nostalgia can help reduce pain, and now a team of Chinese scientists has revealed the brain mechanism behind this relief.
Its description is published in the journal JNeurosci and, according to researchers from the Chinese Academy of Sciences, nostalgia decreases the activity of brain areas related to pain and reduces subjective evaluations of thermal pain.
Specifically, the team led by Kong Yazhuo found that the thalamus, a brain region essential for pain modulation, is also related to the analgesic effect associated with nostalgia, according to two press releases from the Society for Neuroscience, in the United Statesand the Chinese Academy of Sciences.
Nostalgia, a sentimental longing for one’s past, is a self-conscious social emotion, perhaps bittersweet, but predominantly positive. “This helps us maintain a positive psychological state by counteracting the negative impact of difficult situations,” the study authors explain.
Images to measure nostalgia
The adaptive functions of nostalgia are many and one of its effects is pain relief.
To reach their conclusions, the scientists measured the brain activity of adults with functional magnetic resonance imaging (fMRI) as they rated levels of nostalgia from snapshots and rated pain from thermal stimuli.
Nostalgic images depicted scenes and objects from ordinary childhood, such as a popular candy, cartoon TV show, or backyard game, and “control” snapshots depicted scenes and items from modern life.
Viewing nostalgic images reduced pain scores compared to viewing the other images.
In addition, looking at nostalgic photos also decreased activity in the left lingual gyrus and parahippocampal gyrus, two brain regions involved in pain perception.
Most importantly, the researchers say, the anterior thalamus encoded nostalgia and the posterior parietal thalamus encoded pain perception.
Thus, the activity of the thalamus, a brain region involved in the transmission of information between the body and the cortex, was linked to both nostalgia and pain classifications, describe the authors, who explain that the thalamus can integrate information from nostalgia and transmit it to the pathways of pain.
“The thalamus plays a key role as a central functional link in the analgesic effect,” summarizes Zhang Ming.
Homesickness may be a way to relieve low-level pain, such as headaches or mild clinical pain, without the need for drugs, the authors conclude.
This study sheds light on the neural mechanisms underlying nostalgia-induced pain relief, “providing new perspectives for the development and improvement of non-pharmacological psychological analgesia.”
