Music, Math, and Working Memory: Magnetoencephalography Mapping of Brain Activation in Musicians

Abstract

Musical transposing is highly demanding of working memory, as it involves mentally converting notes from one musical key (i.e., pitch scale) to another key for singing or instrumental performance. Because musical transposing involves mental adjustment of notes up or down by a specific amount, it may share cognitive elements with arithmetical operations of addition and subtraction. We compared brain activity during high and low working memory load conditions of musical transposing versus math calculations in classically trained musicians. Magnetoencephalography (MEG) was sensitive to differences of task and working memory load. Frontal-occipital connections were highly active during transposing, but not during math calculations. Right motor and premotor regions were highly active in the more difficult condition of the transposing task. Multiple frontal lobe regions were highly active across tasks, including the left medial frontal area during both transposing and calculation tasks but the right medial frontal area only during calculations. In the more difficult calculation condition, right temporal regions were highly active. In coherence analyses and neural synchrony analyses, several similarities were seen across calculation tasks; however, latency analyses were sensitive to differences in task complexity across the calculation tasks due to the high temporal resolution of MEG. MEG can be used to examine musical cognition and the neural consequences of music training. Further systematic study of brain activity during high versus low memory load conditions of music and other cognitive tasks is needed to illuminate the neural bases of enhanced working memory ability in musicians as compared to non-musicians.

Keywords: calculation; magnetoencephalography (MEG); music training; musical transposing; working memory.

FIGURE 1

Sample stimuli, duration and procedure across the four experimental tasks: (A) the one single-digit calculation task (1D); (B) the five single-digit calculation task (5D); (C) the one-note transposing task (1T); and (D) the five-note transposing task (5T). All stimuli for 1T and 5T were presented on treble clef and all cues (transposing instruments) were presented using word form.

FIGURE 2

Sample results of the MEG recordings (MR-FOCUSS analyses) for an individual participant showing simultaneous frontal and occipital activation at 1,244 ms latency in five-note transposing (5T).

FIGURE 3

Sample results of the MEG recordings (MR-FOCUSS analyses) showing simultaneous frontal and occipital activation at 513 ms latency in five single-digit calculation (5D) for the same participant shown in Figure 2.

FIGURE 4

Number of differences in neural connections: Comparison between five single-digit calculation (5D) versus five-note transposing (5T).

FIGURE 5

Number of differences in neural connections: Intra-right hemisphere, intra-left hemisphere and inter-hemispheric cortical differences in tasks of high working memory load (5D versus 5T), low working memory load (1D versus 1T), and digits only (5D versus 1D).