Pitch and timbre are two primary features of auditory perception that are generally considered independent. However, an increase in pitch (produced by a change in fundamental frequency) can be confused with an increase in brightness (an attribute of timbre related to spectral centroid) and vice versa. Previous work indicates that pitch and timbre are processed in overlapping regions of the auditory cortex, but are separable to some extent via multivoxel pattern analysis. Here, we tested whether attention to one or other feature increases the spatial separation of their cortical representations and if attention can enhance the cortical representation of these features in the absence of any physical change in the stimulus. Ten human subjects (four female, six male) listened to pairs of tone triplets varying in pitch, timbre, or both and judged which tone triplet had the higher pitch or brighter timbre. Variations in each feature engaged common auditory regions with no clear distinctions at a univariate level. Attending to one did not improve the separability of the neural representations of pitch and timbre at the univariate level. At the multivariate level, the classifier performed above chance in distinguishing between conditions in which pitch or timbre was discriminated. The results confirm that the computations underlying pitch and timbre perception are subserved by strongly overlapping cortical regions, but reveal that attention to one or other feature leads to distinguishable activation patterns even in the absence of physical differences in the stimuli.
Bibliographical noteFunding Information:
Received March 2, 2018; revised Feb. 12, 2019; accepted Feb. 13, 2019. Authorcontributions:E.J.A.,J.M.,C.A.O.,andA.J.O.designedresearch;E.J.A.andJ.M.performedresearch;E.J.A., P.C.B., J.M., C.A.O., and A.J.O. analyzed data; E.J.A. wrote the first draft of the paper; E.J.A., P.C.B., J.M., C.A.O., and A.J.O. edited the paper; E.J.A., J.M., and A.J.O. wrote the paper. This work was supported by the National Institutes of Health (Grant R01 DC005216), the High Performance ConnectomeUpgradeforHuman3TMRScanner(Grant1S10OD017974-01),andtheBrainImagingInitiativeofthe College Liberal Arts, University of Minnesota. We thank Andrea Grant, Anahita Mehta, and Jordan Beim for helpful assistance. The authors declare no competing financial interests. Correspondence should be addressed to Emily J. Allen at firstname.lastname@example.org. https://doi.org/10.1523/JNEUROSCI.0588-18.2019 Copyright © 2019 the authors
© 2019 the authors.
- Auditory cortex