Music is sound. Sound is heard. But music is so much more.
Music ignites the brain, orchestrating a neural symphony between the ears. A melody drifts into the ear, spirals down the cochlea, drops individual tones onto waiting receptors. Tones are deconstructed and launched out on a variety of trajectories, simultaneously activating multiple regions of the brain to process the wealth of information embedded in the music. Consider listening to your favorite song; memories and emotions are triggered, the beat plays out in your head, you smile or cry, your body dances in time. Surely experience shapes these perceptions, assigning meaning and emotion to songs. But is the neuronal encoding for musical information actually formed by these experiences or is it an intrinsic property of merely being human?
The adult auditory system is asymmetrical, the right side associated with music and the left with speech. In 2010 researchers in the field of cognition asked if the neural correlates for asymmetrical sound processing were already in place at birth (Perani et al., 2010). To answer this question, they imaged the brains of peacefully sleeping swaddled newborns, only 1 to 3 days from the womb, while playing piano excerpts from top composers of the Baroque and Classical eras. Next, they challenged the babies’ brains by shifting the key of the music, effectively altering the music’s tonal context while maintaining its musical integrity. This allowed the researchers to not only ask how music is perceived outside of rich contextual landscape of experience but also how this perception could be altered by structural changes to the melody.
Music entered the babies’ brains and traveled to the most likely of places, the right (musical) auditory cortex. The auditory cortex is subdivided into hierarchal layers – the primary, secondary, and tertiary cortices. After the initial receipt of musical tones in the primary cortex the other two regions are typically recruited for decoding of complex melodic structures and to initiate motor responses (i.e. tapping and dancing to the beat). At only three days of age the babies’ brains were already engaging all three auditory cortices in an asymmetrical manner. But the music did not stop there; it traveled into the emotional processing centers of the right brain as well. This suggests that the babies were not only perceiving and processing the music but they were also ‘feeling it’.
So what happened when the music tones were altered? When the researchers played the same music but with shifted tonal structure the babies’ brains lit up in both the right and left auditory cortices and emotional processing centers. Why, if the altered music maintained a musical quality, did the left (speech) auditory cortex get involved? In adults we see this left-sided pattern of brain activation when trying to discern irregularities in sound patterns. Perhaps, then, the unexpected nature of the altered tones spiked the little ones’ curiosity, causing them to send the music to the left side of their brains to figure it out. Given that the altered music was still musical in nature this left-side switch likely was the result of surprise associated with the tonal shift instead of failure to recognize the music as, well, music.
Instinctively we know that music can soothe and engage our babies but the degree and effect of this engagement has remained elusive. Overall, this study showed that babies are born into this world with a neural asymmetry for sound processing and a neural-based sensitivity to the structure of sound. Likely this framework was established before birth, even as early as the onset of hearing at only 16 weeks’ gestation. These results are particularly intriguing in the context of the prevailing “use it or lose it” hypothesis in the field of cognitive neuroscience. This hypothesis states that the more a neural circuit is engaged early in life the stronger it becomes, forming a neural scaffold on which learning is built. Conversely, circuits that are not engaged lose strength and disappear from the neural framework. Use it or lose it. This research suggests that music can be used in a new and unexpected way to differentially induce and reinforce neural pathways that may not be activated by traditional music in a newborn baby’s brain.
Perani, D., Saccuman, M. C., Scifo, P., Spada, D., Andreolli, G., Rovelli, R., . . . Koelsch, S. (2010). Functional specializations for music processing in the human newborn brain. Proceedings of the National Academy of Sciences, 107(10), 4758-4763.