ELECTROPHYSIOLOGICAL REPRESENTATION EVOKED BY PHONEME-RELATED RAPID TEMPORAL SEQUENCES IN HUMANS

Proper neural processing of rapid temporal sequences in the auditory system is essential for sound perception and speech understanding. It was shown that phoneme-related rapid sequences of two noise bursts (NBs) separated by a small gap evoke nonlinear transitions in their neural responses. (Burkhard et al., 2019). However, it is not clear whether, and how, this phenomenon relates to the perception of the sound discontinuity (gap detection). The present study focused on an analysis of electrophysiological responses and auditory perception of these NB sequences in humans. EEG signals were recorded using Ag-AgCl electrodes in a group of young probands (n=18) with normal hearing. Durations of the leading noise burst vary (5, 10, 30 ms), whereas durations of the trailing noise burst and a gap were fixed (50, 10 ms, respectively). The stimuli were presented and recorded using Tucker-Davis Technologies system (TDT, Alachua, USA). Probands reported hearing single or double sounds. EEG signals were evaluated for signal change rate and temporal shape similarity. Differences in the recorded event-related potentials were observed in the early (0-250 ms) and late (250-450 ms) response phases in signal change rates and signal shapes, respectively. These features could be attributed to single or double-burst perception with a nonlinear sigmoid-like transition in the psychometric function. We demonstrated the specificity of electrophysiological representations of the studied conditions with direct relations to auditory perception, making them suitable biomarker candidates for the quality of auditory temporal sequence processing in humans.
Supported by NextGenerationEU with RRP for SR: RESYNC 09I03-03-V04-0024.