The Effects of Intelligible Speech on the Phase-Locking of EEG Signals to Audio Stimuli

Recent studies have shown that neural oscillations in the auditory cortex modulate their phase to match the rhythm of acoustic stimuli. This phase-locking phenomenon could have the effect of improving sensitivity to acoustic cues and increasing prediction accuracy. Furthermore, it has been observed that this phase-locking phenomenon in magnetoencephalograpy (MEG) data is enhanced when the audio stimulus contains intelligible and meaningful speech. This study determines if such a phenomenon can also be observed in electroencephalography (EEG) data. Stimuli were processed using a noise-vocoding technique to vary intelligibility while preserving the acoustic envelope. The stimuli were then presented to human subjects randomly while EEG signals from the subjects were being recorded. After processing the data, this phenomenon was not observed in the EEG signal. It is possible that the increased noise inherent in the EEG signal (when compared with the MEG signal) masks out the desired phenomenon.unpublishednot peer reviewedU of I OnlyUndergraduate senior thesis not recommended for open acces