Elsevier

NeuroImage

Volume 226, 1 February 2021, 117545
NeuroImage

Speech frequency-following response in human auditory cortex is more than a simple tracking

https://doi.org/10.1016/j.neuroimage.2020.117545Get rights and content
Under a Creative Commons license
open access

Highlights

  • Frequency-following responses directly observed in the human auditory cortex with intracranial EEG.

  • Both the spectral amplitude and phase coherence of cortical FFR showed significant harmonic preference.

  • The timing fidelity of speech FFR was higher than of harmonic sweeps.

  • The frequency limits of the cortical FFR largely overlapped with the range of human vocal pitch.

Abstract

The human auditory cortex is recently found to contribute to the frequency following response (FFR) and the cortical component has been shown to be more relevant to speech perception. However, it is not clear how cortical FFR may contribute to the processing of speech fundamental frequency (F0) and the dynamic pitch. Using intracranial EEG recordings, we observed a significant FFR at the fundamental frequency (F0) for both speech and speech-like harmonic complex stimuli in the human auditory cortex, even in the missing fundamental condition. Both the spectral amplitude and phase coherence of the cortical FFR showed a significant harmonic preference, and attenuated from the primary auditory cortex to the surrounding associative auditory cortex. The phase coherence of the speech FFR was found significantly higher than that of the harmonic complex stimuli, especially in the left hemisphere, showing a high timing fidelity of the cortical FFR in tracking dynamic F0 in speech. Spectrally, the frequency band of the cortical FFR was largely overlapped with the range of the human vocal pitch. Taken together, our study parsed the intrinsic properties of the cortical FFR and reveals a preference for speech-like sounds, supporting its potential role in processing speech intonation and lexical tones.

Keywords

Frequency-following response
Intracranial EEG
Auditory cortex
Speech
Frequency limits

Cited by (0)

1

These authors contributed equally to this work.