Modulation of phase-locked neural responses to speech during different arousal states is age-dependent

Abstract

Phase-locked responses are vital for auditory perception and they may vary with participants' arousal state and age. Two phase-locked neural responses that reflect fine-grained acoustic properties of speech were examined in the current study: the frequency-following response (FFR) to the speech fundamental frequency (F0), which originates primarily from the auditory brainstem, and the theta-band phase-locked response (θ-PLV) to the speech envelope that originates from the auditory cortices. The ways these responses were affected by arousal in adults across a wide age-range (19 ~ 75 years) were examined. Extracts from electroencephalographic (EEG) responses to repeated syllables were classified into either high or low arousal state based on the occurrence of sleep spindles. The magnitudes of both FFRs and θ-PLVs were statistically greater in the high, than in the low, arousal state. The difference in θ-PLV between the two arousal states was significantly associated with sleep spindle density in the young, but not the older, adults. The results show that (1) arousal affects phase-locked processing of speech at cortical/sub-cortical sensory levels; and that (2) there is an interplay between aging and arousal state which indicates that sleep spindles have an age-dependent neuro-regulatory role on cortical processes. The results lay the grounds for studying how cognitive states affect early-stage neural activity in the auditory system across the lifespan.

What Can Computational Models Learn From Human Selective Attention? A Review From an Audiovisual Unimodal and Crossmodal Perspective

“…Scalp-recorded frequency-following responses (FFRs) are part of auditory brainstem responses (ABR). They are evoked potentials generated from the brainstem area (Mai et al, 2019). FFRs are phase-locked to the envelope or waveform of the lowfrequency periodic auditory stimuli (Zhang and Gong, 2019).…”

Relationship between neural phase-locked responses to speech and perception of speech in noise in young and older adults

“…A webcam monitored the participants throughout the test and no significant changes in head or body position were observed. Participants were not stopped from falling asleep because another specific purpose of the current experiment was to study the effects of arousal on speech-evoked neural processing across ages (Mai et al, 2019), and this purpose was separate from the present study. As it was found that arousal significantly affect the phase-locked responses (Mai et al, 2019), only EEG data from periods with high arousal were used here (see Part 2.4.3 for details).…”

“…Participants were not required to remain awake during the EEG recording because another purpose of the present experiment, which was separate from the present study, was to investigate the effect of arousal on speech-evoked responses (Mai et al, 2019). It was found that both subcortical and cortical responses showed significant suppression in low arousal/nREM states compared to high arousal states (Mai et al, 2019).…”

“…Participants were not required to remain awake during the EEG recording because another purpose of the present experiment, which was separate from the present study, was to investigate the effect of arousal on speech-evoked responses (Mai et al, 2019). It was found that both subcortical and cortical responses showed significant suppression in low arousal/nREM states compared to high arousal states (Mai et al, 2019). This accords with earlier functional imaging work that showed that neural responses to speech in subcortical (Portas et al, 2000) and cortical (Czisch et al, 2004; Wilf et al, 2016) auditory regions reduce during sleep compared to wakefulness.…”

What can computational models learn from human selective attention? A review from an audiovisual crossmodal perspective

“…Scalp-recorded frequency-following responses (FFRs) are part of auditory brainstem responses (ABR). They are evoked potentials generated from the brainstem area (Mai et al, 2019). FFRs are phase-locked to the envelope or waveform of the low-frequency periodic auditory stimuli (Zhang and Gong, 2019).…”