A role for the intraparietal sulcus in transforming musical pitch information.

The present functional magnetic resonance imaging study investigates the neural substrates of relative pitch. Musicians and nonmusicians performed 2 same/different discrimination tasks (simple and transposed melody) that differed in whether they required precise encoding and comparison of relative pitch structure, along with 2 control tasks (rhythm and phoneme). The transposed melody task involved a musical transposition of 4 semitones between the target and comparison patterns, requiring listeners to use interval information rather than the absolute value of the individual pitches. Contrasting the transposed melody to the simple melody condition revealed greater activation in the cortex within the intraparietal sulcus (IPS) bilaterally; control tasks did not elicit significant activity in the IPS. Moreover, a whole-brain voxel-wise regression analysis of brain oxygenation level-dependent signal showed that activity within the right IPS predicted task performance for both musicians and nonmusicians specifically in the transposed melody condition. Successful performance of the transposed melody task requires encoding and comparison of auditory patterns having different tonal reference points-thus simple tonal memory is not sufficient. Our results point to a role for the IPS in transforming high-level auditory information. We suggest that this area may support a general capacity for transformation and comparison of systematically related stimulus attributes.