Cortical envelope-tracking of speech and music using electroencephalography

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Savanna Richard¹, Lukas Grasse¹, Matthew Tata¹; ¹University of Lethbridge

Speech and music are two of the most uniquely human cognitive functions, featuring complex temporal dynamics that are reflected in brain electrical activity. Phase-tracking of the acoustic envelope of speech in the 5-Hz theta band of the electroencephalography (EEG) (and magnetoencephalography (MEG)) is believed to correspond to the 5-Hz syllable rate of speech (Luo and Poeppel, 2007). Less is known about envelope tracking in music, which might be very different from speech because of differences in the number and complexity of component envelopes (Doelling and Poeppel, 2015; Harding et al., 2019). Whereas a single talker presents a single envelope to the listener, polyphonic music (i.e., with melody and harmony) is intentionally a coherent mixture of several envelopes. We investigated the cortical tracking of speech and music by recording brain electrical activity using EEG while participants listened to speech, monophonic music, or polyphonic music. Envelope tracking was measured by cross-correlating the absolute value of the Hilbert transform of the audio envelope with the low-pass filtered EEG signal for each stimulus presentation. Results indicate that music shows a stronger tracking than speech, consistent with the findings of Harding et al. (2019). However, the pronounced tracking of music was driven by the monophonic stimuli. We hypothesize that monophonic music presents a single envelope, similar to speech, but at a more consistent rate and with more stationarity than speech, resulting in stronger tracking.

Topic Area: PERCEPTION & ACTION: Audition