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Examining the extent of neural population overlap for music and speech using noise as a reference stimulus

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Alejandra E Santoyo¹, Kristina C Backer¹, Antoine J Shahin¹; ¹University of California, Merced

There is evidence that music and speech are processed in overlapping neural networks. To further investigate the extent of this overlap, we used an auditory habituation paradigm to examine the N1-P2 auditory-evoked potential (AEP) of speech and music in reference to noise. Previous studies reveal that noise is primarily processed in the primary auditory cortex (AC) while music, and especially speech, further recruit networks in non-primary (higher-level) auditory cortices. Importantly, the amplitude of the N1-P2 AEP reflects the degree of temporal locking of a neural population to sound features. Here, EEG was recorded from eight participants passively listening to four bursts of pink noise, followed by a target sound that was either speech (n-n-n-n-s) or music (n-n-n-n-m); a control condition that consisted of five noise bursts (n-n-n-n-n) was included. We propose that a reduction of the target sound’s N1-P2 amplitude would suggest a greater neural overlap with noise, thus resulting in a weakened onset response to the last sound in the stream. When contrasting the AEPs for the music versus noise (control) target sounds, no significant AEP differences were observed. However, the contrast between the speech and noise (control) target sounds revealed a significant difference in the N1 AEP in frontocentral channels following the target sound’s onset. These preliminary findings suggest that the neural population of speech (high-level AC), as opposed to music, overlaps less with the neural population of noise (low-level AC), highlighting a hierarchical organization of sound processing mediating noise, music, and speech perception.

Topic Area: METHODS: Electrophysiology