TY - JOUR
T1 - Modulation change detection in human auditory cortex
T2 - Evidence for asymmetric, non-linear edge detection
AU - Kim, Seung Goo
AU - Poeppel, David
AU - Overath, Tobias
N1 - Publisher Copyright:
© 2020 Federation of European Neuroscience Societies and John Wiley & Sons Ltd
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Changes in modulation rate are important cues for parsing acoustic signals, such as speech. We parametrically controlled modulation rate via the correlation coefficient (r) of amplitude spectra across fixed frequency channels between adjacent time frames: broadband modulation spectra are biased toward slow modulate rates with increasing r, and vice versa. By concatenating segments with different r, acoustic changes of various directions (e.g., changes from low to high correlation coefficients, that is, random-to-correlated or vice versa) and sizes (e.g., changes from low to high or from medium to high correlation coefficients) can be obtained. Participants listened to sound blocks and detected changes in correlation while MEG was recorded. Evoked responses to changes in correlation demonstrated (a) an asymmetric representation of change direction: random-to-correlated changes produced a prominent evoked field around 180 ms, while correlated-to-random changes evoked an earlier response with peaks at around 70 and 120 ms, whose topographies resemble those of the canonical P50m and N100m responses, respectively, and (b) a highly non-linear representation of correlation structure, whereby even small changes involving segments with a high correlation coefficient were much more salient than relatively large changes that did not involve segments with high correlation coefficients. Induced responses revealed phase tracking in the delta and theta frequency bands for the high correlation stimuli. The results confirm a high sensitivity for low modulation rates in human auditory cortex, both in terms of their representation and their segregation from other modulation rates.
AB - Changes in modulation rate are important cues for parsing acoustic signals, such as speech. We parametrically controlled modulation rate via the correlation coefficient (r) of amplitude spectra across fixed frequency channels between adjacent time frames: broadband modulation spectra are biased toward slow modulate rates with increasing r, and vice versa. By concatenating segments with different r, acoustic changes of various directions (e.g., changes from low to high correlation coefficients, that is, random-to-correlated or vice versa) and sizes (e.g., changes from low to high or from medium to high correlation coefficients) can be obtained. Participants listened to sound blocks and detected changes in correlation while MEG was recorded. Evoked responses to changes in correlation demonstrated (a) an asymmetric representation of change direction: random-to-correlated changes produced a prominent evoked field around 180 ms, while correlated-to-random changes evoked an earlier response with peaks at around 70 and 120 ms, whose topographies resemble those of the canonical P50m and N100m responses, respectively, and (b) a highly non-linear representation of correlation structure, whereby even small changes involving segments with a high correlation coefficient were much more salient than relatively large changes that did not involve segments with high correlation coefficients. Induced responses revealed phase tracking in the delta and theta frequency bands for the high correlation stimuli. The results confirm a high sensitivity for low modulation rates in human auditory cortex, both in terms of their representation and their segregation from other modulation rates.
KW - amplitude modulation
KW - magnetoencephalography
KW - spectrotemporal modulation
KW - temporal edge detection
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U2 - 10.1111/ejn.14707
DO - 10.1111/ejn.14707
M3 - Article
C2 - 32080939
AN - SCOPUS:85081248048
SN - 0953-816X
VL - 52
SP - 2889
EP - 2904
JO - European Journal of Neuroscience
JF - European Journal of Neuroscience
IS - 2
ER -