Intracranial Recordings Reveal Relationship Between Speech-Induced Auditory Suppression and Sensitivity to Auditory Feedback in Human Cortex

Centrala begrepp

Speech-induced auditory suppression in the superior temporal gyrus is correlated with enhanced sensitivity to auditory feedback perturbations, suggesting a common neural mechanism underlying speech monitoring.

Sammanfattning

This study used intracranial electroencephalography (iEEG) recordings from 35 neurosurgical participants to investigate the relationship between speech-induced auditory suppression and sensitivity to auditory feedback in the human cortex.

Key highlights:

• The degree of speech-induced auditory suppression was highly variable across different recording sites in the superior temporal gyrus (STG), with the strongest suppression observed in the middle and posterior parts of the STG.
• Sites in the STG that exhibited strong speech-induced suppression also showed enhanced responses to delayed auditory feedback (DAF), indicating a strong correlation between suppression and sensitivity to auditory feedback.
• This finding supports the hypothesis that auditory suppression during speech production is a key mechanism underlying speech monitoring, enabling the detection of vocal errors.
• The study also found that posterior STG showed larger responses to DAF compared to normal speech production, even when participants received simultaneous feedback, suggesting that increased attention to auditory feedback under adverse speaking conditions can modulate feedback sensitivity in this region.

Overall, the results provide neurophysiological evidence for a shared neural mechanism between auditory suppression and speech error detection, and highlight the role of the posterior STG in attentional modulation of auditory feedback processing during speech production.

Statistik

Voice intensity was similar between the delayed auditory feedback (DAF0) condition and the visual word reading with auditory feedback (VWR-AF) condition (Voice intensity; DAF0: 50±11 dB, VWR: 49±12 dB; paired t-test: t (118) = 1.8, p = 0.08).
Suppression indices for auditory electrodes ranged from -0.46 to 0.53.
Sensitivity indices for auditory electrodes ranged from -0.62 to 0.70.

Citat

"A common hypothesis is that suppressing responses to predicted self-generated stimuli increases sensitivity of the sensory system to external stimuli."
"If speech-induced suppression enables detection and correction of speech errors, suppressed auditory sites should be sensitive to auditory feedback, thus exhibit enhanced neural responses to feedback perturbations."
"Overlapping sites showed enhanced responses to feedback, indicating sensitivity."

Viktiga insikter från

Speech-induced suppression and vocal feedback sensitivity in human cortex

by Ozker,M., Yu... på www.biorxiv.org 12-08-2023

https://www.biorxiv.org/content/10.1101/2023.12.08.570736v3

Djupare frågor

How do the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback differ between healthy individuals and those with speech disorders?

In healthy individuals, speech-induced auditory suppression involves the downregulation of neural responses in the auditory cortex during vocalization, which is thought to enhance sensitivity to external auditory stimuli. This suppression allows for the detection and correction of speech errors by comparing predicted auditory outcomes with actual feedback. On the other hand, sensitivity to auditory feedback perturbations involves an increase in neural responses in the auditory cortex when feedback is altered, indicating the brain's ability to detect discrepancies between expected and actual auditory input.
In individuals with speech disorders, such as apraxia or dysarthria, the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback may be altered. For example, individuals with apraxia may have difficulty coordinating the motor aspects of speech production, leading to atypical patterns of neural suppression and sensitivity in the auditory cortex. Similarly, individuals with dysarthria, which affects the muscles involved in speech production, may show differences in how their brain processes auditory feedback during speech.
Overall, individuals with speech disorders may exhibit disruptions in the typical neural mechanisms of speech-induced auditory suppression and sensitivity to auditory feedback, which could contribute to their difficulties in speech production and monitoring.

How do the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback differ between healthy individuals and those with speech disorders?

In healthy individuals, speech-induced auditory suppression involves the downregulation of neural responses in the auditory cortex during vocalization, which is thought to enhance sensitivity to external auditory stimuli. This suppression allows for the detection and correction of speech errors by comparing predicted auditory outcomes with actual feedback. On the other hand, sensitivity to auditory feedback perturbations involves an increase in neural responses in the auditory cortex when feedback is altered, indicating the brain's ability to detect discrepancies between expected and actual auditory input.
In individuals with speech disorders, such as apraxia or dysarthria, the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback may be altered. For example, individuals with apraxia may have difficulty coordinating the motor aspects of speech production, leading to atypical patterns of neural suppression and sensitivity in the auditory cortex. Similarly, individuals with dysarthria, which affects the muscles involved in speech production, may show differences in how their brain processes auditory feedback during speech.
Overall, individuals with speech disorders may exhibit disruptions in the typical neural mechanisms of speech-induced auditory suppression and sensitivity to auditory feedback, which could contribute to their difficulties in speech production and monitoring.

How do the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback differ between healthy individuals and those with speech disorders?

In healthy individuals, speech-induced auditory suppression involves the downregulation of neural responses in the auditory cortex during vocalization, which is thought to enhance sensitivity to external auditory stimuli. This suppression allows for the detection and correction of speech errors by comparing predicted auditory outcomes with actual feedback. On the other hand, sensitivity to auditory feedback perturbations involves an increase in neural responses in the auditory cortex when feedback is altered, indicating the brain's ability to detect discrepancies between expected and actual auditory input.
In individuals with speech disorders, such as apraxia or dysarthria, the neural mechanisms underlying speech-induced auditory suppression and sensitivity to auditory feedback may be altered. For example, individuals with apraxia may have difficulty coordinating the motor aspects of speech production, leading to atypical patterns of neural suppression and sensitivity in the auditory cortex. Similarly, individuals with dysarthria, which affects the muscles involved in speech production, may show differences in how their brain processes auditory feedback during speech.
Overall, individuals with speech disorders may exhibit disruptions in the typical neural mechanisms of speech-induced auditory suppression and sensitivity to auditory feedback, which could contribute to their difficulties in speech production and monitoring.