PT  - JOURNAL ARTICLE
AU  - Xiangbin Teng
AU  - Qinglin Meng
AU  - David Poeppel
TI  - Modulation Spectra Capture EEG Responses to Speech Signals and Drive Distinct Temporal Response Functions
AID  - 10.1523/ENEURO.0399-20.2020
DP  - 2021 Jan 01
TA  - eneuro
PG  - ENEURO.0399-20.2020
VI  - 8
IP  - 1
4099  - http://www.eneuro.org/content/8/1/ENEURO.0399-20.2020.short
4100  - http://www.eneuro.org/content/8/1/ENEURO.0399-20.2020.full
SO  - eNeuro2021 Jan 01; 8
AB  - Speech signals have a unique shape of long-term modulation spectrum that is distinct from environmental noise, music, and non-speech vocalizations. Does the human auditory system adapt to the speech long-term modulation spectrum and efficiently extract critical information from speech signals? To answer this question, we tested whether neural responses to speech signals can be captured by specific modulation spectra of non-speech acoustic stimuli. We generated amplitude modulated (AM) noise with the speech modulation spectrum and 1/f modulation spectra of different exponents to imitate temporal dynamics of different natural sounds. We presented these AM stimuli and a 10-min piece of natural speech to 19 human participants undergoing electroencephalography (EEG) recording. We derived temporal response functions (TRFs) to the AM stimuli of different spectrum shapes and found distinct neural dynamics for each type of TRFs. We then used the TRFs of AM stimuli to predict neural responses to the speech signals, and found that (1) the TRFs of AM modulation spectra of exponents 1, 1.5, and 2 preferably captured EEG responses to speech signals in the δ band and (2) the θ neural band of speech neural responses can be captured by the AM stimuli of an exponent of 0.75. Our results suggest that the human auditory system shows specificity to the long-term modulation spectrum and is equipped with characteristic neural algorithms tailored to extract critical acoustic information from speech signals.