Musical notes played at octave intervals (i.e., having the same pitch chroma) are perceived as similar. This well-known perceptual phenomenon lays at the foundation of melody recognition and music perception, yet its neural underpinnings remain largely unknown to date. Using fMRI with high sensitivity and spatial resolution, we examined the contribution of multi-peak spectral tuning to the neural representation of pitch chroma in human auditory cortex in two experiments. In experiment 1, our estimation of population spectral tuning curves from the responses to natural sounds confirmed-with new data-our recent results on the existence of cortical ensemble responses finely tuned to multiple frequencies at one octave distance (Moerel et al., 2013). In experiment 2, we fitted a mathematical model consisting of a pitch chroma and height component to explain the measured fMRI responses to piano notes. This analysis revealed that the octave-tuned populations-but not other cortical populations-harbored a neural representation of musical notes according to their pitch chroma. These results indicate that responses of auditory cortical populations selectively tuned to multiple frequencies at one octave distance predict well the perceptual similarity of musical notes with the same chroma, beyond the physical (frequency) distance of notes.
Bibliographical noteFunding Information:
This work was supported by Maastricht University , the Netherlands Organization for Scientific Research (NWO; Rubicon grant 446-12-010 to MM and VICI grant 453-12-002 to EF), the National Institutes of Health (NIH grants P41 EB015894 , P30 NS076408 , and S10 RR26783 ), and the WM KECK Foundation .
- FMRI encoding
- High field functional MRI
- Human auditory cortex
- Octave percept
- Pitch chroma