Today we humans have in our kitty the most amazingly designed systems. As far as intelligent systems are concerned, nothing can match the excellent design and complexity of the human brain. But how responsive is our brain to stimuli? Also, what grade of predictions can it make for anticipatory events? The best way to understand this is to delve into our auditory and motor coordination. A unique research by Dr. Robert Zatorre and his team from the University of McGill focuses on ‘Music’ as a stimuli. The research findings helps open a few knots in the jumbled neural domain of our brains!
Dr. Zatorre presented his work at a conference hosted by the University of Ottawa this past January. He announced that he selects music as the chief stimulus for his work. Does music activate our brain’s reward system? Does music have a similar effect on every body? These are the two major queries and central force driving his research. Dislike for a generally appreciated and accepted pleasurable entity is termed as anhedonia. While I may be astoundingly happy after listening to a rock number, another person might not like the genre at all! This commonly referred phenomena, as a “taste” in music has much deep rooted theory in neural science. Dr. Zatorre also talked about the “chill”. So, if you are listening to your favorite song, and your most favorite part is beginning to play, you feel happy. Sometimes, so happy where you begin to feel a sudden elevation of your senses. This is the chill. The same feeling often fired by alcohol consumption. This of course is attributed to ‘dopamine’, the king of pleasure centres in our brains.
At the beginning of his speech, Dr. Zatorre pointed out the existence of music and musical instruments right from the paleolithic age in human history. The ancient artifacts are significant proof of the fact that our brains were well equipped to understand the intricacies of musical notes. When we listen to music, it is a common observation that we tend to “sway” with the beats. This is nothing but our auditory reflexes guiding activity in our Motor Cortex and neurotransmitters giving our body the signal to move. Pitch, beats and difference in harmonics are separately identified by us. This only indicates that for different elements, there exists a specific neural circuit in our brains. These circuits also work differently for every person. Dr. Zatorre’s team tries to identify the difference in people’s behavioural and physiological responses to spot musical anhedonia and more specifically identify the regions of brain responsible for it.
Using Functional MRI (FMRI) scans, Dr. Zatorre’s team has built a diverse database of people and their response to different musical scores. Three groups of people were formed. The groups divided them into most anhedonic, average anhedonic and hedonic. The FMRI helped in highlighting the brain activity. People experiencing “chills” to a particular segment of music showed higher physiological responses (blood pressure, temperature and heart rate). On the other hand, musically anhedonic people showed flat responses. Evident as it is that music does engage the pleasure centre in our brain. The next question becomes, does it also engage our brain’s reward mechanism? To find an answer to this, the team asked people to rate music they found pleasurable and to also bid money on music they liked. The cash value bidded by people on the music directly varied with their interest in a particular music. Following this, people were made to participate in an activity where they could loose or win money. To win money, people became more proactive, clearly engaging their reward system to “gain”. But, a group of people who were clearly interested in earning more money, at the same time showing very flat response to music indicated the fact that the way we access our brain’s reward system is different for different stimuli. This shows the “dissociation” between musical and monetary reward responses. As further extension of this work, Dr. Zatorre and his team plan to investigate the existence of different accesses to our reward system.
Read the complete details on the work of Dr. Zatorre et.al in an article titled “Dissociation between Musical and Monetary Reward Responses in Specific Musical Anhedonia“. Also, more details on Dr. Zatorre’s research team can be found on the official website of the Zatorre lab.