It was a Friday. You were catching up with a few friends in a bar. The live band was playing some music. “The music is not bad,” you thought, tapping your foot and swaying along with the tempo.

When the band played your favorite song, you jumped into the dance floor, yelling “Yesss!” Keeping up with the beat, you became the dancing queen of the night.

I bet everyone must have experienced the scenario I described above. There is a natural tendency of synchronizing one’s body movements to music tempo in everyone, even in infants (Phillips-Silver & Trainor, 2005). Due to this natural tendency, music is often used as a tool to facilitate synchronization of body movements in a group. For example, the coxswain of a rowing team uses his or her voice cadence to synchronize movements of rowers to achieve efficient rowing and maximum speed. Yet, this natural tendency does not make sense when I try to think from a neurobiological perspective because music is a perceptual event dissociated from action processes. Therefore, what is the neurological mechanism behind this natural tendency?

To answer the question, Chen, Penhune, and Zatorre (2008) studied auditory-motor interactions using fMRI. Participants listened passively to three rhythms in an fMRI scanner without previous exposure to the music. Though the rhythms contained the same number and type of notes, they varied in complexity (simple, complex, ambiguous). After the passive listen session, participants were told that they would learn the rhythms and tap along with the rhythms. Each rhythm was played in two consecutive trials. Participants listened attentively to the rhythm in the first trial, and tapped along with the rhythm in the second trial. The music-tapping task was conducted three times that each rhythm was heard and played.

Surprisingly, various motor areas were found to be activated along with auditory areas in the posterior superior temporal gyrus, encompassing the planum temporale. The mid-premotor cortex (midPMC), the supplementary motor area (SMA), and the cerebellum were activated during passive listen, with no acknowledgement of tapping. The ventral premotor cortex was found to be activated when participants were told to anticipate tapping and during tapping, whereas the dorsal premotor cortex (dPMC) was activated when one’s movement synchronized with the music. Greater involvement of the dPMC was found when the complexity of rhythms increased, which proved dPMC’s potential function in metrical organization. In summary, our brain is hardwired to make us move and synchronized with music regardless of our intention.

Thanks to our delicately programmed brain that everyone is born to dance. However, the activation of motor areas is often associated with action. How is music associated with action? The answer is, the process of making music, argued by Molnar-Szakacs and Overy (2006). Except for recent advance of computer music, music is always made with physical vibrations, which can be initiated through various actions. For example, we move the muscle of vocal cords to sing, we press the keys of piano with fingers, we hit the drum with drumsticks, and etc. The actions associated with the process of producing music are the information that activates the premotor areas, specifically the mirror neuron system. Mirror neurons fire when one initiates certain action and when one sees the behavior performed by someone else. There is a form of “audio-visual” mirror neurons, which are activated when one hears someone else performing certain action (Rizzolatti & Craighero, 2004). For example, the mirror neurons are activated in monkeys when they eat peanuts and when they hear others crack peanuts (Ridley, 2014). So when we listen to music, our “audio-visual” mirror neurons in premotor areas are activated by the actions involved in producing music. They fire as if we are playing the instruments, and the general activation in premotor areas triggers our desire to move and dance.

The existence of “audio-visual” mirror neurons indicates that we are not only inborn dancers, but we are also inborn musicians! There are also various neurological benefits of dance and music mentioned in a previous post by Zusi. The benefits of music can be extended to behavioral level that music synchronization can improve our running performance argued by Kaitlin in another previous post. Let’s celebrate art with our natural gift for music and dance!

References

Chen, J. L., Penhune, V. B., & Zatorre, R. J. (2008). Listening to musical rhythms recruits motor regions of the brain. Cerebral cortex, 18(12), 2844-2854.

Molnar-Szakacs, I., & Overy, K. (2006). Music and mirror neurons: from motion to ’e’motion. Social Cognitive and Affective Neuroscience, 1(3), 235–241. http://doi.org/10.1093/scan/nsl029

Ridley, M. (2004). The agile gene: How nature turns on nurture.

Rizzolatti, G., & Craighero, L. (2004). The mirror-neuron system. Annu. Rev. Neurosci., 27, 169-192.