I remember hearing an amazing story of Rubinstein in one of my history classes: he was on a train to a concert, and, either the programme had changed, or, he hadn’t had time to learn one of the pieces (César Franck’s Symphonic Variations, I think), so he ended up looking at the score on the train. He read the score over and by the time he reached the concert, he played it. Admittedly, he did have photographic memory, but this had to be coupled with an amazing ability to hear the music in his head—to practice it without a piano. As a pleasant anecdote, apparently, he would play Brahms’ symphonies in head over breakfast, too.
Anyways, all of this to say, musical or auditory imagery is important to all musicians, and is something that has not been studied with much success. We understand that auditory imagery is common, but we don’t know how auditory features are represented in the brain during imagery. Even doing a simple search throughout academic and non-academic search engines, I found articles and websites about guided imagery and meditation, and very little about the phenomenon of musical imagery in the lives of musicians.
According to an extensive Ph.D thesis by Bailes (2002), musical imagery has three difference manifestations: one, that it is unintentional and happens spontaneously, such as an earworm; second, that it is involuntary, but a result of musical activity; and third, that it is intentional through imagining a score, just as Rubinstein did.
Auditory imagery and perception share neural pathways, and from my understanding there is a difference between mental representations of music and the actual imagining of music. If one consciously tried to imagine a piece, note by note, bar by bar, it requires mental effort—give it a try. Pick a song you know very well or know how to play and imagine playing it, looking at the score and hearing the sound. It is very different than simply passively letting a song flow through your mind. This is the type of musical imagery looked at in the following study.
Martin et al. (2017) very recently completed a study that determined an interesting way of looking at auditory imagery that may actually provide a means to furthering our knowledge about it. It was a case study of a trained pianist who was getting brain scans for epilepsy. The authors recorded electrocorticograhic signals (ECoG) during two conditions: in one, the pianist would play two pieces on a keyboard (set up with MIDI) as per normal, but the second condition, the pianist would play the same piece without being able to hear auditory feedback. The pianist was told to imagine the pieces while playing them on a soundless keyboard. The keyboard still recorded MIDI for this second condition. Therefore, for both the perception and the imagery conditions, the ECoG of the neural activity and the recorded musical features could be compared and analyzed temporally.
For those of you who are interested in the more in-depth brain-focused information, I will let you peruse the article at your own will, but here I will mention only some of the findings. Overall, they found precise time locking between the neural activity, the music and the features of musical imagery, suggesting that there is shared representation between perception and imagery, as shown by the spectrotemporal representations of the perceptual data and the imagery data. With regards the brain activation, there was a strong relationship between musical temporal features and the superior temporal gyrus (which contains the primary auditory cortex), but this was dependent on the cortical location. They also found that, in both conditions, electrodes had the highest prediction accuracy in superior and middle temporal gyrus, pre-and post-central gyrus and supramarginal gyrus. Furthermore, the perception and imagery conditions were correlated under this prediction model. Therefore, because the music perception condition and the musical imagery condition had the same stimulus, this provides support to the theory that perception and imagery use shared representation of spectrotemporal features of sound.
There were some limitations to their study: they only recorded the left temporal lobe, even though both hemispheres are important in musical processing, and it is nearly impossible to know that the task of imagining the piece was actually completed. There is no concrete method to determine if the pianist actually imagined the piece as he was supposed to, however, the MIDI recordings for both conditions are very similar, suggesting that the pianist “heard” the piece in both conditions.
Auditory imagery has still a ways to go in order to be understood, but I think that this study is a strong and beneficial step towards a deeper and more full understanding of a phenomenon so important to musicians of all levels.
Bailes, F. A. (2002). Musical imagery: Hearing and imagining music. (Unpublished doctoral dissertation). Universit of Sheffield, Sheffield, England.
Martin, S. et al. (in press). Neural encoding of auditory features during music perception and imagery: Insight into the brain of a piano player. bioRxiv. Advance online publication. doi: 10.1101/106617.