Spatiotemporal Mapping of Auditory Onsets during Speech Production

Area of Science:

• Neuroscience
• Auditory Perception
• Speech Processing

Background:

• The human auditory cortex processes speech based on timing and spectral features.
• Posterior superior temporal gyrus responses differentiate acoustic boundaries (onset) and phonological content (sustained).
• The auditory system monitors self-produced speech for real-time error correction, leading to suppressed neural responses during speech production.

Purpose of the Study:

• To investigate whether auditory onset and sustained responses are differentially affected during speech production compared to perception.
• To determine the functional role of auditory onset responses in speech perception versus production.

Main Methods:

• Intracranial electroencephalography (iEEG) was recorded from 17 patients (pediatric, adolescent, adult) with epilepsy.
• Patients performed a reading/listening task to elicit speech perception and production.
• Analysis focused on identifying and comparing onset and sustained auditory responses in the cortex and insula.

Main Results:

• Both onset and sustained speech responses were identified in the bilateral auditory cortex.
• A selective suppression of onset responses was observed during speech production compared to perception.
• Phonological feature tuning remained stable for suppressed onset responses between perception and production.
• Auditory onset responses and phonological tuning were also found in the posterior insula during both perception and production.

Conclusions:

• Auditory onset responses, vital for speech perception timing, are suppressed during speech production as they become redundant with predictive mechanisms.
• The posterior insula may represent a distinct auditory processing area involved in multisensory integration and feedback control during speech.