Neural Substrates Associated with Character Amnesia in Chinese Handwriting: A Functional Near-infrared Spectroscopy...

Area of Science:

• Neuroscience
• Cognitive Psychology
• Linguistics

Background:

• Chinese speakers often experience character amnesia, the inability to handwrite characters they recognize.
• The underlying causes, including orthographic lexicon access, graphemic buffer, and phonology-orthography links, remain unclear.

Purpose of the Study:

• To investigate the neural correlates of character amnesia using functional near-infrared spectroscopy (fNIRS).
• To determine if character amnesia is associated with deactivation in the fusiform gyrus (FG), superior parietal gyrus (SPG), or supramarginal gyrus (SMG).

Main Methods:

• A handwriting-to-dictation task was administered to 23 Cantonese-speaking adults.
• fNIRS was used to measure brain activation during correct handwriting versus instances of character amnesia.

Main Results:

• Character amnesia showed reduced activation in the bilateral FG, SPG, and SMG compared to correct handwriting.
• Character frequency correlated with FG activation, and stroke count correlated with SPG activation.
• Decreased functional connectivity was observed between FG and SMG, and FG and SPG during character amnesia.

Conclusions:

• Character amnesia is linked to decayed orthographic representations and impaired phonology-orthography conversion.
• These deficits lead to reduced retrieval of orthographic information for handwriting execution.