The neurobiology behind the Christmas spirit

by Antonino Napoleone, Ivy Rose Sebastian | December 23, 2022.

Tis the season to be jolly! When we think of Christmas, we are mentally transported to twinkling lights that adorn cities, huge Christmas trees lined with the most varied decorations marking city squares, Christmas markets tinged with red and green hues, exuding warmth with popular music and carols resounding in the air tangled with the delicious aroma of cinnamon, freshly baked sweets and all sorts of yummy treats!

All this along with cosy get-togethers with friends and family are not incidental phenomena, but part of a broader social context on which many focused scientific studies exist.

If one investigates deeply enough, any social or interactive phenomenon involving humans has an epicentre of a molecular nature. That is, our body responds to external stimuli in an active and dynamic manner, creating associations and connections with the external environment through biological processes. If ‘molecules’ are involved, somewhere in the world there would also be a scientist studying the mechanisms of these molecules. So, here’s how some curious and fascinating results came about: evidence was found that the ‘Christmas spirit‘ produces a generally positive effect on those who celebrate it, triggered and regulated by the release of specific neurohormones.

The hormonal response to external stimuli influences the way we interact with others, our moods, states of happiness and euphoria, as well as other physiological functions, such as appetite. So, does the Christmas spirit really exist and how does our body respond during the festive season? Let’s discover some interesting facts together about the neurobiology of Christmas!

The Christmas spirit and neurohormonal regulation 

Neurobiology is a fascinating science that deals with studying the fundamental mechanisms by which the neuroendocrine system coordinates certain biological and behavioural functions, and the resulting responses to external environmental stimuli. Christmas may have an effect at the hormonal level, producing changes in normal biological rhythms.

In fact, it is not far-fetched to admit that these changes and the external triggers produce a new ‘Christmas’ biological rhythm (which varies from person to person) that can last throughout the Christmas period. It is precisely these external triggers around us that cause the physiological changes and in reality, during the pre-Christmas period, there is a progressive change in the sensory stimuli we are exposed to, and these may include:

• Visual stimuli such as lights, Christmas decorations, trees and Christmas presents, 
  
• Olfactory stimuli arising from the smells of sweets, spices and winter fruits,
  
• Palate stimuli originating from traditional dishes, sweets and hot drinks,
  
• Auditory stimuli from typical Christmas carols, the sound of bells or musical instruments,
  
• Tactile stimuli from contact with loved ones, greetings and hugs from family members.

What hormones regulate the mood?

Following up on these hypotheses were several transverse studies, e.g. a German research group from the University of Dresden Medical School, examined how certain olfactory attributes change depending on the context and time of year. It was seen how certain odours such as cloves, cinnamon and orange were immediately associated with Christmas. In fact, it has been seen that at Christmas time, the smell of cinnamon generates amplified feelings of pleasantness and familiarity and is perceived differently than at other times of the year.

At the neuroendocrine level, Christmas produces an effect that varies from subject to subject. We could assume that various Grinches do not experience the same positive effect at this time of the year, but in general, the state of euphoria and happiness caused by Christmas may be linked to the peripheral effect of neurohormones released into circulation by the hypothalamic-pituitary axis (Figure 1). What hormones control the mood?

• Serotonin (5HT): also known as the ‘feel-good hormone‘. Serotonin is involved in appetite control and determines the onset of satiety. At the level of the central nervous system, a drop in serotonin causes pathological drops in mood, and thus, also causes anxiety and depression.
  
• Dopamine: also known as the ‘euphoria hormone‘. Dopamine increases when we do something that we enjoy and gives us pleasure. It is released by the hypothalamus and has several functions in the central nervous system, such as control of movement, control of mnemonic capacity, control of mood, and regulation of the feeling of pleasure.
  
• Oxytocin: alternatively called the ‘love hormone‘, it is produced by the hypothalamus and secreted by the neurohypophysis. Oxytocin is said to be closely correlated with the formation of an emotional bond between individuals. The release of oxytocin produces various positive feelings such as empathy, trust, relaxation, positive emotion, and decreased anxiety.

The neuronal network of the Christmas spirit

Believe it or not, we are convinced that the Christmas spirit really exists and that it is able to stimulate physiological changes mixed with amplified associations and sensory stimuli. The question that has arisen among some researchers at the Danish Headache Centre and Department of Neurology is whether there really is a Christmas spirit, and if so, in which part of our body does it reside and what biological mechanisms are involved?

A remarkable attempt was made to find an answer by using functional magnetic resonance imaging (fMRI) to examine the neuronal connections in the brains of 26 individuals examined in the study. fMRI is an exceptional tool that has been successfully used for several years in neurophysiology studies to examine functional centres and brain activity. In this study, changes in brain activity following exposure to Christmas stimuli were examined by comparing a group of individuals accustomed to celebrating Christmas to a control group without any Christmas traditions or habits. 

The results of the study showed how the two groups responded differently to Christmas stimuli; images obtained with fMRI revealed activation in certain areas of the brain near different cortical areas, the parietal lobules, premotor cortex and somatosensory cortex. According to the researchers, these areas could be representative of a real neural network of Christmas!

Conclusions

Christmas is a phenomenon that entirely embraces those who welcome it and experience it by being immersed in a variety of colours, scents, lights and flavours. We have seen that this multitude of stimuli is processed by our nervous system and converted into a cascade of hormones and increased activity in certain brain areas that can affect our mood. However, we are convinced that we do not always need rigorous scientific data to believe that Christmas can have a general effect on our state of euphoria and happiness related to this special time of year. This article is intended to support the idea that after all, the Christmas spirit, somehow may bring some changes, all we need to do is to be able to let ourselves get caught up in this atmosphere of positivity and conviviality. And, after a year in the lab, we deserve a little light-heartedness and relaxation!

Merry Christmas from the Sciencerely team!

References

• Hougaard A, Lindberg U, Arngrim N, Larsson H B W, Olesen J, Amin F M et al. Evidence of a Christmas spirit network in the brain: functional MRI study BMJ 2015; 351 :h6266 doi:10.1136/bmj.h6266
• Seo HS, Buschhüter D, Hummel T. Odor attributes change in relation to the time of the year. Cinnamon odour is more familiar and pleasant during Christmas season than summertime. Appetite. 2009;53(2):222-225. doi:10.1016/j.appet.2009.06.011
• Ludwig M. Christmas: an event driven by our hormones? J Neuroendocrinol. 2011;23(12):1191-1193. doi:10.1111/j.1365-2826.2011.02244.x
• Funny part of Biology for Christmas (the-dna-universe.com)