TY - JOUR
T1 - Human cortical activity during streaming without spectral cues suggests a general neural substrate for auditory stream segregation
AU - Gutschalk, Alexander
AU - Oxenham, Andrew J.
AU - Micheyl, Christophe
AU - Wilson, E. Courtenay
AU - Melcher, Jennifer R.
PY - 2007/11/28
Y1 - 2007/11/28
N2 - The brain continuously disentangles competing sounds, such as two people speaking, and assigns them to distinct streams. Neural mechanisms have been proposed for streaming based on gross spectral differences between sounds, but not for streaming based on other nonspectral features. Here, human listeners were presented with sequences of harmonic complex tones that had identical spectral envelopes, and unresolved spectral fine structure, but one of two fundamental frequencies (f0) and pitches. As the f0 difference between tones increased, listeners perceived the tones as being segregated into two streams (one stream for each f0) and cortical activity measured with functional magnetic resonance imaging and magnetoencephalography increased. This trend was seen in primary cortex of Heschl's gyrus and in surrounding nonprimary areas. The results strongly resemble those for pure tones. Both the present and pure tone results may reflect neuronal forward suppression that diminishes as one or more features of successive sounds become increasingly different. We hypothesize that feature-specific forward suppression subserves streaming based on diverse perceptual cues and results in explicit neural representations for auditory streams within auditory cortex.
AB - The brain continuously disentangles competing sounds, such as two people speaking, and assigns them to distinct streams. Neural mechanisms have been proposed for streaming based on gross spectral differences between sounds, but not for streaming based on other nonspectral features. Here, human listeners were presented with sequences of harmonic complex tones that had identical spectral envelopes, and unresolved spectral fine structure, but one of two fundamental frequencies (f0) and pitches. As the f0 difference between tones increased, listeners perceived the tones as being segregated into two streams (one stream for each f0) and cortical activity measured with functional magnetic resonance imaging and magnetoencephalography increased. This trend was seen in primary cortex of Heschl's gyrus and in surrounding nonprimary areas. The results strongly resemble those for pure tones. Both the present and pure tone results may reflect neuronal forward suppression that diminishes as one or more features of successive sounds become increasingly different. We hypothesize that feature-specific forward suppression subserves streaming based on diverse perceptual cues and results in explicit neural representations for auditory streams within auditory cortex.
KW - Adaptation
KW - Auditory cortex
KW - MEG
KW - Scene analysis
KW - Stream segregation
KW - fMRI
UR - http://www.scopus.com/inward/record.url?scp=36849014887&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36849014887&partnerID=8YFLogxK
U2 - 10.1523/JNEUROSCI.2299-07.2007
DO - 10.1523/JNEUROSCI.2299-07.2007
M3 - Article
C2 - 18045901
AN - SCOPUS:36849014887
SN - 0270-6474
VL - 27
SP - 13074
EP - 13081
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 48
ER -