Group and individual variability in speech production networks during delayed auditory feedback

Area of Science:

• Neuroscience
• Speech Science
• Cognitive Science

Background:

• Altering sensory feedback, such as introducing delayed auditory feedback (DAF), significantly impacts speech production, leading to voice and loudness changes and dysfluencies.
• Individual differences in susceptibility to DAF exist, but the underlying neural mechanisms remain poorly understood.

Purpose of the Study:

• To investigate the neural basis of speech fluency changes under varying DAF conditions (50 ms and 200 ms).
• To identify neural correlates of within- and between-subject variability in DAF susceptibility.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to examine brain activity during speech production under two DAF conditions.
• Speech fluency was rated, and these ratings were correlated with neural activity patterns.

Main Results:

• Neural networks for speech production under DAF largely overlap with those active during normal speech.
• Midbrain periaqueductal gray activity was associated with fluency, independent of the DAF condition.
• Variability in speech fluency under 200 ms DAF correlated with ventral sensorimotor cortex activity.
• Left inferior frontal gyrus activity was associated with fluency under 50 ms DAF.

Conclusions:

• Overlapping cortical mechanisms support speech production under different DAF temporal delays.
• Susceptibility to distinct temporal delays in auditory speech feedback may involve separable neural processes.