Differentiating maturational and training influences on fMRI activation during music processing

Abstract

Two major influences on how the brain processes music are maturational development and active musical training. Previous functional neuroimaging studies investigating music processing have typically focused on either categorical differences between "musicians versus nonmusicians" or "children versus adults." In the present study, we explored a cross-sectional data set (n=84) using multiple linear regression to isolate the performance-independent effects of age (5 to 33 years) and cumulative duration of musical training (0 to 21,000 practice hours) on fMRI activation similarities and differences between melodic discrimination (MD) and rhythmic discrimination (RD). Age-related effects common to MD and RD were present in three left hemisphere regions: temporofrontal junction, ventral premotor cortex, and the inferior part of the intraparietal sulcus, regions involved in active attending to auditory rhythms, sensorimotor integration, and working memory transformations of pitch and rhythmic patterns. By contrast, training-related effects common to MD and RD were localized to the posterior portion of the left superior temporal gyrus/planum temporale, an area implicated in spectrotemporal pattern matching and auditory-motor coordinate transformations. A single cluster in right superior temporal gyrus showed significantly greater activation during MD than RD. This is the first fMRI which has distinguished maturational from training effects during music processing.

Fig. 1

Sample stimuli for the MD and RD task. Asterisks indicate a change in Phrase 2.

Fig. 2

Task performance (d′) as a function of Age, Training, and Task (MD vs. RD). r-values are partial correlations.

Fig. 3

Thresholded activation in the average subject SPMs. (a) Activation common to both MD and RD (scatter plot inserts visualize the simple correlations between Age and the mean β-value from each active cluster). (b) A different scatter plot illustrating the similarity of voxel values between second-level MD>S and RD>S average subject SPMs. (c) Significantly increased activation in MD relative to RD. Abbreviations: pre-SMA: presupplementary motor area; STG: superior temporal gyrus. r-values are partial correlations with p<.05 (*) or p<.001 (***). The scatter plot was made using a custom-built data visualization toolbox (http://tools.robjellis.net).

Fig. 4

Thresholded activation in the MD∧RD positive partial correlation with Age. Scatter plots visualize the simple correlations between Age and the mean β-value from each active cluster in temporofrontal junction (a), premotor cortex (b), and intraparietal sulcus (c). r-values are partial correlations with p<.001 (***).

Fig. 5

Thresholded activation in the MD∧RD positive partial correlation with Training. Scatter plots visualize the simple correlations between Training and the mean β-value from the active cluster. r-values are partial correlations with p<.001 (***).