Imagine some 40,000 years ago, a vulture bone with precise and delicate holes along its length was used to play a tune by a human. In 2013, a recent archeology finds of this object most likely means that instruments have existed for thousands of years already. Neuroscientists can safely infer therefore that music is among the most ancient of human cognitive traits. This is one of the first steps towards researching the neuroscience of the brain on music and possibly answering why an individual may find music pleasurable or not.
Neuroscience is essentially the study of the all the sciences and how they deal with a structure or function with the nervous system or brain. To make it clear, the study of music through neuroscience is just another way to understand what music is. Music is a form of art, and art is a very hard thing to measure or understand and therefore neuroscience may help provide a better understanding of this phenomena.
In a journal article, written by Robert Zatorre and Valorie Salimpoor, called ‘From Perception to Pleasure: Music and Its Neural Substrates’, first look at the neurobiology of musical cognition. Both writers asked the question of how evolution may have specifically shaped the human auditory system, and what is the most characteristic of the way we use sound. An obvious answer would be that humans use sounds to communicate our emotions and mental representations. While taking this approach, one may say that music and speech can be thought of in the same way. Many other articles have taken this approach as well, which helps solidify that this approach may be the best approach towards researching the neuroscience of music.
Many factors must go into determining what music may be and how humans perceive music. Due to needing to research many known and unknown factors, researching neuroscience and music can be very difficult. Many scientists do their best in measuring the factors they thought of as most important in how it may affect the way humans understand music. Again, in the journal written by Zatorre and Salimpoor, they discuss the neuroscience behind perception, pleasure and reward and the connections they have to the way humans perceive music. Music evokes pleasure which is linked to reward, and studying musical pleasure gives a set of hypotheses that serve as a framework.
First, when looking at the neurobiology of the brain and music, it is useful to consider features of non-humane primate auditory cortex to help determine both homologies and unique properties. The primate auditory cortex is like visual and somatosensory systems in the sense that both are organized in a hierarchical manner. Core areas are surrounded by the belt and parabelt within the superior portion of the temporal lobe, which allows for corresponding patterns of feedback loops and feedback projections. A common organizational feature across species are the pathways starting in the core areas that have two eventual targets in separate areas of the frontal cortices and so are best thought of bidirectional. This architecture creates a series of functional loops that allow for integration of auditory information with other modalities. The superior portion of the temporal lobe main function is to process sensory information and derive it into meaningful memories, language, and emotions.
The frontal cortex controls important cognitive skills, emotions, language, problem solving. In essence, it controls our personality and our ability to communicate. “It has been shown that other cortical areas within or outside the temporal lobe are activated when listening to music or discriminating specific music components” (Avanzini, 2012, par. 18). Writers Zatorre and Salimpoor found the same thing when looking at neuroimaging of patients listening to music. Neuroimaging is a very important tool and has been shown to be profitable towards the research of neuromusic. When the superior portion and frontal cortices are active in patients listening to music, this means the brain is working to process the music through the patient’s past perceptions, memories and expectations. The frontal cortex holds all of a human’s past memories, using them to make sense of sounds they hear in the present. For example, when someone hears the word ‘hello’, the frontal cortices process that the word ‘hello’, through past experiences and memories that it is a way of greeting.
With what has been found through neuroimaging, it is still unclear as to how humans are able to distinguish speech and music from each other. A neuroimage from Avanzini’s book also shows that both the right and left hemisphere of our brains are working. Our right cerebral hemisphere specializes in pitch, with an accurate pitch mechanism both in perception and production. The left cerebral hemisphere specializes in speech sounds that do not require as great of accuracy in pitch tracking. It can be inferred that somewhere in the right hemisphere of our brain is where humans are able to distinguish speech from music.
Going back to considering features in a non-human primate auditory cortex helps better explain why humans may find pleasure and reward in music. “In the animal kingdom, the phylogenetically ancient mesolimbic reward system serves to reinforce biologically significant behaviors, such as eating, sex, or caring for offspring” (Zatorre & Salimpoor, 2013, par. 16). Reward is based off our need to survive. Animals have this mechanism to reward anything that helps the species be successful in surviving by releasing dopamine. “However, as animals become more complex, additional factors become important for successful survival” (Zatorre & Salimpoor, 2013, par. 16). For simple animals, factors that affect survival involve food, shelter, and reproduction, but for more complex animals like humans, making money is a factor that impacts how successful our survival is. Understanding how the reward system in our brains work helps give a clearer understanding of musically meditated pleasure.
In the world of neurobiology, a reward can be thought of as something that produces a hedonic sense of pleasure. This means that humans can derive a pleasurable sensation from behaviors that induce reward. in theory humans are able to understand the conceptual value of an abstract item that does not inherit reward value, like the reward value humans see in money, due to reinforcing qualities of secondary rewards. In line with this, stimuli that are conceptually meaningful and have little to no relevance with survival and yet many people obtain pleasure from these stimuli. A new question that the two writers, Zatorre and Salimpoor, now propose, is: ‘How does a seemingly abstract sequence of sounds produce such potent and reinforcing effects?’.
To answer this, understanding how the brain understands music is important. Physicist Burkhard Maess and colleagues at the Max Planck Institute of Cognitive Neuroscience in Leipzig, Germany, conducted an experiment that involved right-handed patients listening to five chords in the key of C major that ended, following a convention, on the tonic (C major) chord. The second and third chord sequences threw in a wild card: a ‘Neapolitan’ chord that contains two notes that are found in the key of C major. When inserted as the third in the five-chord sequence, this chord is a bit incongruous. What the experiment was measuring was how right-handed people’s brains would react to a set of chords, with the last chord being put into fifth position as the first four chords set an expectation of the ending of the tonic (C major) chord. With magnetoencephalography (MEG) to measure these responses from the set of chords, the team found the in-key chords mainly registered in the primary auditory cortex, but the incongruent set lit up areas above and in front of the temporal lobe, in the speech area, and its corresponding region on the right. This helps reinforce the theory that music and speech are related in neurobiology and can also help explain how the brain distinguishes the two. A possible explanation of why the speech area of the brain, also known as Broca’s area, and its right hemisphere mate lit up in the MEG because those two areas are given the responsibility of making sense of the wrong sounding notes in the last chord. The subjects in the experiment had no musical training and with these MEG results, this helps solidify existing evidence that the brain has an implicit ability to apply harmonic principals to music (Holden, 2001, par. 4). All of these findings help support other findings that music and language share the same brain regions when being processed. This brings to attention when talking about ‘language areas’ of the brain, it should not be taken at face value. These findings conclude the experiment by raising the question of what our brains areas are really doing. This part of neuromusic and neurobiology research is still yet to be understood completely by researchers and scientists but there are still many other questions that need to be answered.
Music seems to understand music through patterns of notes like a chord, which is what the experiment before uses a way to measure the brain’s activity. This idea opens the question that writers Zatorre and Salimpoor raise is: ‘Why do certain combinations of sounds seem aesthetically pleasant to humans, but not to other animals, even primates?’. Coming back to mesolimbic systems in humans and animals, it is found that many organisms have mesolimbic striatal regions, but the anatomical connectivity of these regions with the rest of the brain varies across species depending on the complexity of the brain. Furthermore, as animals become more complex, the concept of reward can take on different forms. This shows another way to approach the new question. First the writers define the music they are examining would be a sequence of sounds that have certain pitches and tones, and then play with the concepts of reward, perception, and pleasure, which is the main theme throughout their journal article. Since the regions that light up when music is being processed involve perception, there is a theory that when humans hear a sequence of sounds, several templates may be activated to fit the incoming auditory information. This process will inevitably lead to a series of predictions that may be confirmed or violated, and ultimately determine its reward value to the individual. The experiment done by Burkhard Maess uses a sequence of sounds, or chords to which they found their subjects creating expectations which were broken on the last chord. This is evidence that humans may have predictions when listening to music which correlates to reward and pleasure. These predictions seem to lead to activity in the mesolimbic striatal regions. The mesolimbic striatum has previously been associated with anticipation. Within the mesolimbic system, the dorsal striatum and prefrontal cortexes are involved in functions that help with relating information from earlier events, planning ahead, creating expectations, etc. These cognitive processes are highly significant in musical processing, which means it is likely that the mesolimbic system provides a mechanism for temporal nuances that rise feelings of anticipation and craving. Therefore, it is likely that the cerebral cortex and striatum work together to make predictions about potentially rewarding events and assess the outcome of predictions.
All the findings, theories, and evidence help neuroscientists better understand what our brains our doing when ingesting music. As well as what music may be and why it is pleasurable to humans although it is not necessarily something we may need to survive. There has only been 2 decades of research on the neuroscience of music, but the research has given opportunities for fields involved in science and neurology. Basic research shows that the field of music, physiology and cognition has an opportunity in creating individualized and precision medicine approaches. Music provides a tool to study numerous aspects of neuroscience.