EVOKED ARTICULATORY RESPONSE DURING INTERNAL AND EXTERNAL SPEECH

Shevchenko Andrey O., Vartanov Alexander V.

This study is aimed at identifying the time intervals of dynamic speech for the subsequent analysis of the evoked EEG potentials. Understanding of exact time intervals will allow to make better use of pattern classification possibilities for BCI (brain-computer interface). The study involved 7 subjects with the following stimuli: 7 phonemes (A - [a], B - [b], F - [f], G - [g], M - [m], R - [p], U - [u]) presented in random order, EMG envelope was used for recording: the subjects were to mentally repeat the phoneme or syllable with the duration and intonation that correspond to these units in external speech. As a result of the study, average potentials were plotted for all subjects during internal phonemic utterance, external utterance (vocalization), and perception of phonemes without their repetition. The results show a close connection between phonemic perception and articulation: phonemic perception reveals articulatory activity, while articulatory commands act as anticipatory discharges due to a connection between motor and auditory centers; the amplitude of internal articulation and phonemic enunciation are similar.

Keywords:evoked potentials, inner speech, neurolinguistics, subvocalization, phonemes, phonemic perception