Neural circuitry underlying sentence-level linguistic prosody.

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Speech prosody, encompassing stress and intonation, is crucial for conveying meaning in spoken language.
• Understanding the neural basis of prosody perception is key to comprehending language processing.
• Mandarin Chinese, a tonal language, may recruit different neural resources for prosody compared to non-tonal languages like English.

Purpose of the Study:

• To investigate the neural substrates of contrastive stress and intonation perception in Mandarin Chinese.
• To compare the brain activity of Mandarin Chinese and English listeners during prosody discrimination tasks.
• To explore the role of hemispheric asymmetries in processing different aspects of speech prosody.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to measure brain activity.
• Participants (Mandarin Chinese and English speakers) performed speeded discrimination tasks focusing on either stress or intonation.
• Paired 3-word sentences were used to elicit specific prosodic contrasts.

Main Results:

• The Chinese group showed greater activation in the left supramarginal gyrus and posterior middle temporal gyrus for both tasks compared to the English group.
• Leftward asymmetry in these regions was observed in the Chinese group during the stress task.
• Both groups exhibited rightward asymmetry in the middle frontal gyrus and bilateral activation in the intraparietal sulcus.

Conclusions:

• Speech prosody perception involves a dynamic interplay between distributed neural regions across both hemispheres.
• Left hemisphere regions are critical for language processing, while right hemisphere regions support complex sound analysis.
• Language background influences the neural networks engaged in processing sentence-level prosody.