By Hrayr Attarian, MD
Language and music are both universal human phenomena that transcend cultural barriers. Improvisation is as old as music itself; however, in the genre we call jazz it became a sort of a central tenet. For centuries, musicians have improvised as a tool to perfect the final iteration of their work. In that regard, it is used as a means to an end. In jazz, improvisation is both the means and the end. For the last few decades, neuroscientists have been interested in brain functions associated with musical performance in general—and spontaneous creativity in particular. One of their essential tools is brain mapping: a technique that localizes different functions to distinct regions of the cerebral cortex (brain surface).
Mapping would not have been possible without the pioneering work of one Korbinian Brodmann. A German neurologist at the turn of the last century, Brodmann published his classic treatise in 1909 identifying 52 anatomically and cellularly distinct areas on the cortex of each hemisphere (half) of the human brain.
Subsequent work by others demonstrated that at least some of the “Brodmann areas” had unique functions. For instance, areas 41 and 42 are involved in hearing; they communicate with area 22, responsible for language comprehension, and areas 44 and 45, responsible for language output. They are also connected to the secondary and tertiary auditory areas, 40 and 39 respectively. Here, it is important to point out that the above apply to the dominant—in the majority of people, the left—hemisphere. Dominance in neurologic lingo refers to the side of the brain responsible for language. This is not the same as the pop-science, highly questionable, concept of being a right brain/left brain person.
Figure 1 is a map that shows all the areas mentioned in the article.
Listening to Music:
When it comes to listening to music, the primary auditory areas (41, 42) identify the fundamental elements such as pitch and volume. The secondary area, 40, processes melody and harmony. Meanwhile, area 39, the tertiary area, is involved in appreciation of music as well as higher processing of language and math. All four areas also connect to the limbic system, in the inner part of each hemisphere, responsible for emotions—hence, the emotional impact of music.
Figure 2 is a diagram of the limbic system.
In general, when sounds are brief, areas 41 and 42 of the dominant hemisphere perceive the relative duration and distribution of notes or rhythm. When sounds are longer, corresponding regions of the non-dominant hemisphere are also involved. Harmony—the way simultaneous tones relate to one another—and timbre—the specific difference in sound of more than one instrument playing the same notes—are usually non-dominant hemisphere functions.
Functional magnetic resonance imaging (fMRI) is a scientific tool that maps brain function during specific tasks and superimposes it on images of brain structure.
Figure 3: Functional MRI in action.
It has helped scientists identify yet another area that becomes active in music appreciation: Brodmann area 10. This relatively large region is also involved in executive function, high-level planning, and memory. When a listener expresses enjoyment in certain music, fMRI has demonstrated increased activation in areas of the brain associated with sexual and food pleasure as well as addiction. Music appreciation, therefore, involves multilevel processes of memory, emotion, and higher mental functioning—making it a unifying experience. Curiously, people exhibit the same response whether they are actually listening to music or playing a song in their head.
This is obviously an overly simplified explanation of a dynamically complex phenomenon.
Research with fMRI has shown that musicians activate a larger area of their dominant hemisphere’s auditory areas than non-musicians when listening to music but not to other sounds. In fact, musicians also have larger auditory areas than nonmusicians with size being commensurate with level of training. This size difference is not confined to auditory areas but also involves those of coordination and manual dexterity with, again, the size correlating with years of experience.
Certain brain regions are more active, and others virtually shut down when improvising, as opposed to playing a preset series of notes. Areas of the brain involved in planning, monitoring one’s self and self-censorship are virtually shut down, while areas involved in storytelling—and those involved in risk taking and intense pleasure—show increased activation.
Therefore, improvisation involves a certain level of abandon, increased creativity, and significant pleasure associated with both. This is something musicians and music lovers already knew except now we can actually translate these abstractions into scientific facts by visualizing where and how in the brain these happen. Figure 4 shows fMRI data in shades of blue—the brain areas that are quiescent—and in shades of orange and red—those that are very active during improvisation. The image has been superimposed on the drawing of a skull for orientation.
Comparison between Interpreting and Improvising:
In 2019, scientists at Georgia State University asked jazz musicians to alternatively sing a pre-learned melody and vocally improvise. Both times the subjects were inside an fMRI machine. During improvisation, as compared to interpreting a song, there was a higher concentration of activity in several key areas with less connectivity among them. These include Brodmann areas 44 and 45 involved in language output, area 6 and other regions involved in control of movement, and areas 9 and 46 responsible for executive functions and cognitive flexibility among other tasks.
Benefits of Improvisation:
Cognitive flexibility is the mental ability to switch between thinking about two different concepts, and to think about multiple concepts simultaneously. Some of the same researchers from the Georgia State University used standardized tests to study cognitive flexibility among 155 seventh- and eighth-grade students. All subjects received 2 months of instruction in jazz scales, vocabulary, and phrasing—but only half of them were taught to improvise. Upon retesting, cognitive flexibility was significantly improved in the improvisation group but not the other one. Therefore, in addition to being one of the highest forms of creativity, improvisation also has cognitive benefits even among adolescents.
In conclusion, thanks to modern science, we now know exactly where music comes from and what happens while listening, playing, and improvising. It also has shown us that all three have significant neurological benefits that translate to more robust brain structure in some regions and better cognitive functioning. This knowledge does not, however, rob this unique art form of its mystique by reducing it to a number of nervous impulses; in fact, the more we unravel its complexity, the more beautiful and awe-inspiring it becomes.
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