Speech compensation responses and sensorimotor adaptation to formant feedback perturbations

Area of Science:

• Speech production
• Motor control
• Auditory feedback

Background:

• Speech sound production relies on feedback and feedforward control.
• The interplay between feedback and feedforward learning in speech is not fully understood.
• Online feedback control is known for pitch and loudness, but its role in vowel formants is unclear.

Purpose of the Study:

• To investigate if feedback control mechanisms, similar to those for pitch and loudness, are involved in vowel formant production.
• To determine if online feedback compensation for formants is distinct from sensorimotor adaptation.

Main Methods:

• Examined speaker responses to unpredictable vowel formant feedback perturbations.
• Analyzed within-trial compensatory responses and across-trial sensorimotor adaptation.
• Investigated the time course dynamics of responses during adaptation.

Main Results:

• Speakers showed similar compensatory responses to formant perturbations at utterance onset and mid-utterance.
• Within-trial online compensation was not correlated with across-trial sensorimotor adaptation.
• Sensorimotor adaptation did not arise from incorporating within-trial compensation.

Conclusions:

• Online feedback compensation and sensorimotor adaptation in speech production are governed by distinct neural mechanisms.
• These findings challenge integrated models and suggest separate pathways for immediate and adaptive speech motor control.
• Implications for understanding how feedback and feedforward control are implemented in speech.