A closer look at musical chills
For most of us, music arouses deep emotions even with songs saying a few words or no words at all. But why?
An ancient rhythm
Music has been part of our culture since the early days of humankind and evidence showing the use of musical instruments goes as back as the Paleolithic period with bone made flutes from 35000 years ago!
The oldest song
Unfortunately, it is impossible to know how paleolithic flute songs used to sound as written records were not part of human behavior yet, but luckily there is a clay tablet containing the oldest musical notation we know so far.
The Hurrian Hymn N°6, discovered in Ugarit Syria, has survived for 3,400 years, so in a way listening to it is like traveling in time. If you want to travel to the past, a representation of the melody can be found on SoundCloud.
Is all about rewards
Music has been previously linked with enjoyable emotional reactions but a direct link with dopamine was not tested until 2011.
Dopamine is a neurotransmitter which is involved in the brain reward system having an essential role in motivation and reinforcement.
In the study, the authors evaluated dopamine release in the striatum, a part of the brain related to motor control and the reward system, using ligand-based positron emission tomography (PET) scanning.
During PET scanning a small (and safe) amount of a radioactive tracer is injected into the bloodstream. Then positrons emitted by the tracer collide with tissue’s electrons releasing photons that are later recorded by PET detectors. This technique can be used to have a closer look at the blood flow or to a molecule of interest.
In this case, it was [11C]raclopride, a molecule capable to interact with dopamine receptors. By using it, a competition for binding the dopamine receptor occurs, between the subject’s dopamine and the tracer.
Then, when comparing two situations of interest an increase in tracer levels tell us that less endogenous dopamine is present and the other way around.
In this way, it is possible to have a sense of the amount of dopamine release at a given brain location, in this case during “chills” or “musical frisson”… but how to measure the chills?
The best part of the song
Fortunately, it is well documented how our bodies react during “musical chills” and several psychophysiological measurements can be done like respiration and heart rates, skin conductance or blood volume pulse.
From the PET scanning, the authors found a positive correlation between the intensity of chills reported by the study subjects and the dopamine release in the nucleus accumbens.
More interestingly, dopamine is also released right before the “chills”. This time by using a different technique called functional magnetic resonance imaging in which brain activity is measured as a reflection of oxygen levels in the bloodstream.
Music is usually based on building and releasing tension and making use of the listener’s anticipation towards patterns that change along the song. It seems like both predicting and guessing the patterns is what makes music so enjoyable.