When Music Meets Brain?

I came across this beautiful picture, titled "When Music Meets Brain." But I'm craving to know, what is it? A neural structure involved in music processing, or an artistic rendering of a creative mind?

Though I can't quite understand it, we can still glean something from it. It's another example of the philosophy of neuroaesthetics: Understanding the science behind the art allows us to enhance our appreciation of both science and art.

A Mona Lisa Mystery: The Science Behind the Smile

Da Vinci’s Mona Lisa is celebrated for her mysterious smile. At every glance, her countenance seems to change slightly. Upon turning our gaze away from her mouth, we may experience the strange sensation that she is smiling more, as if mocking us. Yet, as soon as we focus our eyes once again upon her mouth, we find she is smiling just as she was before. Is there a method behind this seeming madness? Is it a trick of the light, or a trick of the mind?

Margaret Livingstone (2002), Harvard neuroscientist, suggests that this phenomenon may be because Mona Lisa’s smile is more apparent when seen in coarse resolution. Therefore, in the periphery of our vision, where there are larger receptive fields that are poor in perceiving detail, Mona Lisa appears to be smiling more. When we look directly at Mona Lisa’s mouth, we are able to process detail much more effectively because the receptive fields of cells in our central vision (fovea cells) are much smaller. As a result, Mona Lisa’s smile fades as we focus our gaze to her mouth. In the picture below, note how Mona Lisa's seems to smile more in coarse resolution (as in peripheral vision), and smile less in fine resolution (as in central vision).

From Vision and Art: The Biology of Seeing, by M. Livingstone, 2002, p.73

Another theory for the appeal of Mona Lisa’s smile is that angles of her mouth activate area V5 (the area for processing motion) and the frontal cortex. Neurologist A. Chakravarty (2010), author of "Mona Lisa's smile: a hypotheses based on a new principle of art neuroscience," suggested that Da Vinci “[introduced] an element of implicit dynamism, an imagination of movement of a smiling face, in the painting to increase the aesthetic value of his art work”. According to Chakravarty, Mona Lisa’s smile is appealing because it calls upon one’s imagination of movement. However, Chakravarty’s claim seems quite broad, and does not specify what is it about Mona Lisa’s smile that makes it any different from other subtle smiles that also call upon one’s imagination of motion.

Despite the detailed neuroaesthetics of Mona Lisa’s mouth, we have barely begun to scratch the surface of this great masterpiece. In addition to the enigma of Mona Lisa’s smile, there is still, for example, the enigma of how her eyes seem to follow the viewer and the dynamics of the background. Most importantly, there is the profusion of cultural questions regarding the style of the time period, the identity of Mona Lisa, and Mona Lisa’s relationship to Da Vinci . These questions are important aspects of art that neuroaesthetics could never encompass to address.

World Science Festival 2009: Notes and Neurons

The full program of the World Science Festival 2009: Notes and Neurons: In Search of the Common Chorus is available online, in five convenient parts. For now, I just want to share a video excerpt from this program featuring Bobby McFerrin titled The Power of the Pentatonic. It's a fun clip that conveys the universality of music in humans, and speaks to music as being hard-wired in the brain. Watch and enjoy these three minutes.

Program Excerpt:
Bobby McFerrin demonstrates the power of the pentatonic scale, using audience participation, from the June 12, 2009 World Science Festival event "Notes & Neurons: In Search of the Common Chorus". Also on stage are panelists Jamshed Bharucha, Provost and Senior Vice President of Tufts University; the James McGill Professor of Psychology and Neurosciences at McGill University, Daniel Levitin; Professor of Cognitive Neuroscience at the University of Sheffield, Lawrence Parsons; and host of WNYC’s music/talk show Soundcheck, John Schaefer

World Science Festival 2009: Bobby McFerrin Demonstrates the Power of the Pentatonic Scale from World Science Festival.

The Elusive "Groove"

What is groove? I asked my 12-year-old sister and she casually responded, "Anything that is groovy has groove". I asked her what groovy meant, and she answered, "It has rhythm...and it's funky. I mean not funky, but, um...." and became silent. Why is groove so easy to feel yet so hard to define?

I was first inspired to look into the meaning of "groove" after listening to a contemporary concert by Steve Mackey (contemporary composer and chair of the Princeton Music Department) and his students. Mackey is a brilliant modern composer, I recommend listening to his A Beautiful Passing. Anyway, I wondered what science had to say about groove, and found this:


JSTOR: Music Perception: An Interdisciplinary Journal, Vol. 24, No. 2 (Dec., 2006), pp. 201-208

The paper titled "Experiencing Groove Induced by Music: Consistency and Phenomenology" from Music Perception by Guy Madison discusses an experiment that tries to probe into the role of groove in music by having subjects rate pieces of music on various characteristics such as “groove, driving, simple, flowing, happy...bouncing, having swing”. Here is the abstract:

THERE is A QUALITY OF MUSIC THAT makes people tap their feet, rock their head, and get up and dance. The consistency of this experience among listeners was examined, in terms of differences in ratings across 64 music examples taken from commercially available recordings. Results show that ratings of groove, operationally defined as " wanting to move some part of the body in relation to some aspect of the sound pattern," exhibited considerable interindividual consistency. Covariance patterns among the 14 rated words indicated four prominent factors, which could be labeled regular- irregular, groove, having swing, and flowing. Considering the wide range of music examples used, these factors are interpreted as reflecting psychological dimensions independent of musical genre and style.

They discovered that groove contributed to the second largest proportion of variation among all ratings, pointing to the importance of groove as a dimension of music (although they only included “music with a beat” in their music samples). And, they found that groove has no simple relation to tempo, or “having swing."

It’s interesting how science often seems to reduce and then expand artistic concepts. The paper starts by clearly defining “groove” as "wanting to move some part of the body in relation to some aspect of the sound pattern," but ultimately reveals that groove isn’t clearly attributable to any characteristic. So, I guess in the end, it all goes back to the elusiveness of “groove.”

Brainbow: Brain Connectivity in Color

The recent article on the Princeton University website, "Virus 'explorers' probe inner workings of the brain", discusses how Princeton University researches are developing new methods of exploring brain connectivity through the use of virology. Genetically engineered viruses are able to leave color tracks as they travel through neurons, and through the use this technology, aptly termed "Brainbow," and a protein called CRE, neural connections can be studied. The significance of this is that unlike conventional tracers, Brainbow has the capability of distinguishing sections within a given circuit, as described below:

Enquist and his collaborators are using genetic engineering techniques to direct certain neurons, such as those that control a particular body function, to produce CRE. When the neurons that have been engineered to make CRE are infected by the new viral tracer, they will be different colors from infected neurons that are not making CRE. This will allow the researchers to see different subcircuits in the brain, Enquist explained.

Such technology has wide-spread implications for our understanding of the brain, including music and the brain. If neurons involved in certain specifics of music processing, say rhythm, can be genetically modified to produce CRE, then perhaps we can better understand specific circuits involved in music processing.