Tracking the dynamic representation of consonants from auditory periphery to cortex.

Area of Science:

• Neuroscience
• Auditory Processing
• Speech Perception

Background:

• The human auditory system must discern speech sounds from complex acoustic signals.
• Understanding the neural mechanisms of speech perception is crucial for addressing hearing impairments.

Purpose of the Study:

• To investigate the cortical processing of phonemes using electroencephalography (EEG).
• To compare neural representations of speech sounds at the auditory nerve and cortex.
• To link speech sound characteristics to their neural encoding.

Main Methods:

• Measured evoked cortical responses to spoken consonants using EEG.
• Applied multivariate pattern analysis (MVPA) to EEG data to quantify cortical dissimilarity between consonants.
• Modeled auditory-nerve (AN) responses and applied MVPA to compare peripheral and cortical representations.

Main Results:

• Cortical dissimilarity between consonants correlated with their articulatory features, especially manner of articulation.
• EEG-based distinctions at 130 ms and 400 ms post-stimulus onset corresponded to peripheral auditory-nerve dissimilarities.
• Speech sound representations are transformed across auditory processing stages.

Conclusions:

• Cortical processing reflects articulatory properties of speech sounds.
• Auditory pathway transformations are key to speech perception.
• This study advances understanding of how the brain decodes speech.