Evidence for the role of the right auditory cortex in fine pitch
resolution.
Neuropsychologia, 46 (2):
632--9 (Januar 2008)DOI: 10.1016/j.neuropsychologia.2007.09.004
Zusammenfassung
The neural basis of human pitch perception is not fully understood.
It has been argued that the auditory cortices in the two hemispheres
are specialized, such that certain right auditory cortical regions
have a relatively finer resolution in the frequency domain than homologous
regions in the left auditory cortex, but this concept has not been
tested directly. Here, we used functional magnetic resonance imaging
(fMRI) to test this specific prediction. Healthy volunteers were
scanned while passively listening to pure-tone melodic-like sequences
in which the pitch distance between consecutive tones was varied
in a parametric fashion. As predicted, brain activation in a region
of right lateral auditory cortex, corresponding to the planum temporale,
was linearly responsive to increasing pitch distance, even across
the fine changes in pitch. In contrast, the BOLD signal at the homologous
left cortical region was relatively constant as a function of pitch
distance, except at the largest pitch change. The results support
the model of relative hemispheric specialization and indicate that
the right secondary auditory cortex has a finer pitch resolution
than the left.