RT Journal Article
SR Electronic
T1 Processing of Natural Sounds: Characterization of Multipeak Spectral Tuning in Human Auditory Cortex
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 11888
OP 11898
DO 10.1523/JNEUROSCI.5306-12.2013
VO 33
IS 29
A1 Michelle Moerel
A1 Federico De Martino
A1 Roberta Santoro
A1 Kamil Ugurbil
A1 Rainer Goebel
A1 Essa Yacoub
A1 Elia Formisano
YR 2013
UL http://www.jneurosci.org/content/33/29/11888.abstract
AB We examine the mechanisms by which the human auditory cortex processes the frequency content of natural sounds. Through mathematical modeling of ultra-high field (7 T) functional magnetic resonance imaging responses to natural sounds, we derive frequency-tuning curves of cortical neuronal populations. With a data-driven analysis, we divide the auditory cortex into five spatially distributed clusters, each characterized by a spectral tuning profile. Beyond neuronal populations with simple single-peaked spectral tuning (grouped into two clusters), we observe that ∼60% of auditory populations are sensitive to multiple frequency bands. Specifically, we observe sensitivity to multiple frequency bands (1) at exactly one octave distance from each other, (2) at multiple harmonically related frequency intervals, and (3) with no apparent relationship to each other. We propose that beyond the well known cortical tonotopic organization, multipeaked spectral tuning amplifies selected combinations of frequency bands. Such selective amplification might serve to detect behaviorally relevant and complex sound features, aid in segregating auditory scenes, and explain prominent perceptual phenomena such as octave invariance.