Evidence of a “Christmas Spirit” network in the brain

The Christmas spirit has been a widespread phenomenon for centuries, commonly described as feelings of joy and nostalgia mixed with associations to merriment, gifts, delightful smells, and copious amounts of good food. It is yet to be determined, however, where in the human body this “Christmas spirit” resides and which biological mechanisms are involved. We attempted to localise the Christmas spirit in the human brain using functional magnetic resonance imaging (fMRI).

Since its inception in the early nineties, fMRI has been instrumental in neuropsychological studies localising emotional and functional centres in the human brain. Feelings such as joy, sorrow, and disgust have been isolated to certain cerebral regions. We used a similar technique by comparing a group of people who have celebrated Christmas since their youth with a group having no Christmas traditions. We scanned the two groups while they were viewing various images and analysed changes in brain activity when they were viewing images with yuletide themes as opposed to regular images.

Our hypothesis was that the two groups would respond differently to Christmas images based on their differences in exposure to Christmas celebrations.

Throughout the world, we estimate that millions of people are prone to displaying Christmas spirit deficiencies after many years of celebrating Christmas. We refer to this as the “bah humbug” syndrome. Accurate localisation of the Christmas spirit is a paramount first step in being able to help this group of patients. Location of the Christmas spirit could also contribute to a more general understanding of the brain’s role in festive cultural traditions, making a medical contribution to cross cultural festivities and goodwill to all.

Based on the results of the questionnaire, 10 participants were allocated to the “Christmas group” (eight men, two women) and 10 to the “non-Christmas group” (eight men, two women). The six remaining participants were excluded either because of a strong Christmas connection despite having no tradition of celebrating Christmas (n=2) or non-positive associations with Christmas despite having a cultural background involving regular Christmas celebration. We analysed MRI data only from included participants. Those in the “Christmas group” were ethnic Danes who celebrated Christmas according to Danish tradition, while those in the “non-Christmas group” were Pakistani (n=2), Indian (n=2), Iraqi (n=1), or Turkish (n=2) expatriates or people of Pakistani descent (n=3) who were born in Denmark.

The baseline perfusion scans showed a normal cerebral perfusion of 54 mL/100g/min without any significant difference between the two groups (P=0.26). Activation maps from fMRI scans showed an increase of brain activity in the primary visual cortex (P<0.001) of both groups when the images viewed had a Christmas theme compared with the everyday images.

The Christmas group also had significant increases in neural activations in the primary somatosensory cortex when the images had a Christmas theme.

Comparison of the brain activation maps of the two groups showed five areas where the Christmas group responded to Christmas images with a higher activation than the non-Christmas group. These areas of difference include the left primary motor and premotor cortex, right inferior/superior parietal lobule, and bilateral primary somatosensory cortex (P<0.001). In contrast, there were no areas of the brain where the non-Christmas group had significantly larger responses to Christmas images than the Christmas group.

Story Source: Materials provided by The BMJ. Note: Content may be edited for style and length.

To access the complete study, including images of the cerebral activity, click here

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