Neural tracking of speech in typically listening individuals
Cortical tracking of speech
Cortical brain oscillations may play important roles in various human cognitive processes. We conducted one of the first EEG studies that tried to identify cortical oscillatory indices for different linguistic (phonological and semantic) levels during spoken language processing:
Along this line, we further studied predictive coding of speech processing by showing the roles of cortical tracking at different frequency bands may play for neural ‘sharpening’ (neural responses to expected semantic inputs) vs. prediction errors (responses to unexpected semantic inputs):
Recent efforts also looked at how cortical tracking of pitch contours indexes effortful listening of speech in noisy environments in typically listening individuals:
Subcortical tracking of speech
‘Frequency-following response’ (FFR) is a subcortical (albeit extra auditory cortical sources) phase-locked response to the speech fundamental frequency, known as a potential index for various hearing and language-related disorders (e.g., hearing loss, developmental dyslexia, autism). We studied FFR in typical listening by looking at how FFR is affected by changes in day-to-day psychophysiological status, e.g., arousal or consciousness, across the adult lifespan:
We also looked at how changes in neural excitability in the auditory cortex (via neurostimulation tDCS) led to consequential changes in subcortical FFR revealing causal auditory subcortico-cortical interactions:
