Neural correlates and functional connectivity of lexical tone processing in reading

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Lexical tone processing in spoken language relies on superior temporal and inferior prefrontal areas.
• The neural underpinnings of processing lexical tone in written language, particularly in reading, remain largely unexplored.

Purpose of the Study:

• To investigate the neural systems involved in processing lexical tone during visual Chinese word recognition.
• To compare the neural circuitry of lexical tone in reading versus speech.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to examine brain activity.
• Seed-to-voxel connectivity analyses were conducted to identify functionally connected regions.

Main Results:

• Extraction of lexical tone phonology in print engaged bilateral fronto-parietal regions.
• Key connected areas included the right inferior frontal gyrus, supplementary motor area (SMA), right middle frontal gyrus, right inferior parietal lobule, and bilateral cingulate gyri.
• Temporal regions vital for auditory tone identification were not involved in reading tone.

Conclusions:

• Chinese tone reading utilizes a bilateral network encompassing frontal, parietal, motor, and cingulate regions.
• This network differs from the auditory processing network for tones, highlighting modality-specific neural adaptations.
• The motor cortex emerges as a potentially modality-independent key component in lexical tone processing.