In a paper published October 2012, Kimihiro Nakamura, Wen-Jui Kuo, Felipe Pegado, Laurent Cohen, Ovid J. L. Tzeng, and Stanislas Dehaene hypothesize “that, across all different cultures, the mature reading network comprises both a visual shape analysis system and a motor gesture decoding system.” They suggest that “this extended network is universal and that only its amount of activation is modulated according to the variable processing demands of writing systems. A motor memory for writing […] is known to play a general role in literacy acquisition in alphabetic literacy acquisition. Such gestural coding during reading may rely on a fast neural pathway […] that automatically recovers the intended motor gestures underlying visually perceived handwritten traces […].
The paper is titled “Universal brain systems for recognizing word shapes and handwriting gestures during reading,” See: www.pnas.org/cgi/doi/10.1073/pnas.1217749109
“[O]our results support the proposal that the expert reading network universally comprises two distinct pathways: an orthographic decoding system in the VWFA (reading by eye) and a kinesthetic gesture code system in Exner’s area (reading by hand). […] Our view predicts that the gesture code of writing should play a much greater role in reading when the expert VWFA system is not fully developed, either in early stages of reading acquisition or in the earlier ages of the literate human history when handwriting was used as a dominant medium for writing. Indeed, recent developmental data show that reading acquisition is facilitated when young children are taught to write or finger-trace the letter shapes compared with classical grapho-phonemic teaching without a haptic component. Conversely, fMRI of normal and dyslexic children also suggests that reading difficulties lead to a greater reliance on the left Exner’s area, suggesting partial compensation through the gesture system.
“Our results further suggest that a large part of the known cultural variations in the cerebral reading network may represent merely a differential weighting of the universal visual and gestural coding systems. Some writing systems, such as Chinese, Japanese, or Tamil, remain strongly centered on a realistic depiction of handwriting strokes, whereas others, including the Roman alphabet, are stylized to the point of using unique shapes for printed letters that even expert literates can no longer write (e.g., the shape of a printed letter g). We suggest that the former systems more systematically engage the gestural reading system […]. […] In the present study, this region, although contributing to both cultures, was more strongly engaged by moving than by static words in Chinese than in French participants, possibly because motor memory clearly plays a key role in memorizing the thousands of characters needed for fluent Chinese reading. Conversely, the VWFA, although universally involved in reading, is more activated in English than in Italian, presumably because of the greater number of graphemes needed in a nontransparent compared with a transparent alphabetic language.
[A]t a […] macroscopic level, we propose that cultural variability lies primarily in the different emphasis that distinct writing systems place on the visual and gestural pathways, thus resulting in modulations of the spatial extent and amplitude of brain activity within culturally universal brain circuits."