With Thanksgiving now behind us, the sounds of Christmas seem to flood the airwaves. Some songs are lively and joyful, while others are slow and contemplative. But whatever the tune, there’s an undeniable familiarity that comes with hearing those omnipresent songs associated with “the most wonderful time of the year.”

For some, these tunes conjure childhood memories of decorating the tree, baking cookies or decking the halls. Maybe our memories are loaded with nostalgia, linking a specific song to a person or place. Regardless of our personal experiences, for four weeks out of the year, these ever-present songs have a known, physical effect on the brain. Like it or not, our brain is tuned to recognize and respond to these seasonal songs.

When we repeatedly experience a certain stimulus—such as a sound or song—nerve cells (neurons) in our brain start to respond selectively to this stimulus. This is what neuroscientists call “neural tuning,” and it allows certain brain cells to recognize the stimulus as something important. The way neural cells and pathways become connected in response to different songs may be linked to memory.

Researchers used functional magnetic resonance imaging, or MRI, to examine how people’s neural connections changed when they heard different songs. When the study participants listened to songs they liked and disliked, there was strong connectivity between the brain region responsible for sound processing (auditory cortex) and the region responsible for memory and social-emotional consolidation (hippocampus). Connectivity is a measure of how quickly and efficiently information is transmitted between different brain regions. In this case, there was speedy transmission between sound processing and active memory formation when participants listened to music.

However, when participants listened to their favorite songs, researchers found that connectivity between the auditory cortex and the hippocampus was separate. The researchers think this was because participants already had stored memories and emotions related to their favorite songs, which the brain was actively retrieving instead of making new connections.

You might wonder what this means for us when we hear the jaunty tune of “Rudolph the Red-nosed Reindeer” or the dulcet crooning of Bing Crosby’s “White Christmas.” Whether we love or loathe these holiday songs, our brain is primed to recruit our memory and emotional centers when we hear these songs, resulting in a differently connected—and perhaps even nostalgic—brain.

Meghan Willcoxon is a PhD student in cognitive science at Brown University in Providence, Rhode Island. She researches how people self-organize and move collectively through a crowd. Willcoxon was the 2022 American Physiological Society-sponsored AAAS Mass Media Science and Engineering Fellow at the Milwaukee Journal Sentinel.