Looking at pictures of good times with family or friends evokes nostalgia, which is also a positive feeling, although bittersweet. Nostalgia can help reduce pain, and now a team of Chinese scientists has revealed the brain mechanism behind this alleviation.
Its description was published in the journal JNeurosci, and according to researchers from the Chinese Academy of Sciences, nostalgia reduces the activity of pain-related brain regions and lowers subjective assessments of heat pain.
Specifically, the team led by Kong Yazhou found that the thalamus, a brain region key to pain modulation, is also linked to the analgesic effect associated with nostalgia, according to two press releases from Neuroscience Society of the United StatesChinese Academy of Sciences.
Nostalgia, an emotional longing for one’s past, is a self-conscious social emotion, perhaps bittersweet, but mostly positive. “This helps us maintain a positive psychological state by counteracting the negative impact of difficult situations,” the study authors explain.
Pictures to measure nostalgia
The adaptive functions of nostalgia are numerous and one of its effects is pain relief.
To reach their conclusions, the scientists measured brain activity in adults using functional magnetic resonance imaging (fMRI) as they rated levels of nostalgia from the shots and assessed pain from thermal stimuli.
Nostalgic photographs depicted ordinary childhood scenes and objects, such as a popular dessert, a cartoon TV show, or a backyard game, and “control” shots depicting scenes and items from modern life.
Viewing nostalgic images reduces pain scores compared to viewing other images.
In addition, looking at nostalgic images resulted in decreased activity in the left lingual gyrus and the parahippocampal gyrus, two brain regions involved in pain perception.
Importantly, the researchers say, the anterior thalamus encodes nostalgia and the posterior parietal thalamus encodes pain perception.
Thus, activity of the thalamus, a brain area involved in transmitting information between the body and the cortex, was associated with both nostalgia and pain ratings, the authors describe, who show that the thalamus can integrate information from nostalgia and transmit it to pain pathways.
Zhang Ming summarizes: “The thalamus plays a major role as the central functional link in the analgesic effect.”
The researchers concluded that homesickness may be a way to relieve low-level pain, such as headaches or mild clinical pain, without the need for medication.
This study sheds light on the neural mechanisms underlying the alleviation of nostalgia-induced pain, “providing new perspectives for the development and improvement of non-pharmacological psychological analgesia.”
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