Frequency-Specific Neural Response and Cross-Correlation Analysis of Envelope Following Responses to Native Speech and Music Using Multichannel EEG Signals: A Case Study

TL;DR

This study investigates the frequency-specific neural responses to speech and music using multichannel EEG, revealing dominant alpha and gamma band responses and neural coherence patterns across scalp locations, advancing understanding of auditory processing.

Contribution

It introduces a novel frequency domain analysis of envelope following responses in EEG, identifying key spectral components and neural coherence patterns in speech and music perception.

Findings

Alpha (8-11 Hz), lower gamma (53-56 Hz), and higher gamma (78-81 Hz) are peak response frequencies.

Neural coherence is prominent at 10-13 Hz, 27-29 Hz, and 62-64 Hz across scalp channels.

Distributed neural processes are involved in native speech and music perception.

Abstract

Although native speech and music envelope following responses (EFRs) play a crucial role in auditory processing and cognition, their frequency profile, such as the dominating frequency and spectral coherence, is largely unknown. We have assumed that the auditory pathway - which transmits envelope components of speech and music to the scalp through time-varying neurophysiological processes - is a linear time-varying system, with the envelope and the multi-channel EEG responses as excitation and response, respectively. This paper investigates the transfer function of this system through two analytical techniques - time-averaged spectral responses and cross-spectral density - in the frequency domain at four different positions of the human scalp. Our findings suggest that alpha (8-11 Hz), lower gamma (53-56 Hz), and higher gamma (78-81 Hz) bands are the peak responses of the system. These frequently appearing dominant frequency responses may be the key components of familiar speech perception, maintaining attention, binding acoustic features, and memory processing. The cross-spectral density, which reflects the spatial neural coherence of the human brain, shows that 10-13 Hz, 27-29 Hz, and 62-64 Hz are common for all channel pairs. As neural coherences are frequently observed in these frequencies among native participants, we suggest that these distributed neural processes are also dominant in native speech and music perception.