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Sophia Vinci-Booher, Neha Sehgal, Felipe Munoz-Rubke, Karin James; Perceptual and Motor Effects of Letter Writing on Brain Regions Associated with Letter Perception. Journal of Vision 2016;16(12):678. doi: https://doi.org/10.1167/16.12.678.
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© ARVO (1962-2015); The Authors (2016-present)
Visual perception of individual letters recruits fusiform gyri(FG), parietal cortex(PC), and frontal cortex(FC); however, letter-selective responses are often associated with the L-FG. All of these regions respond most strongly for letterforms with which the observer has experience hand-printing. Therefore, letter perception responses should be similar to letter printing responses and sensitive to the motor component of letter printing. During fMRI scanning, 6 literate adults hand-printed letters and shapes with and without ink, perceived dynamic re-presentations of their own hand-printed letters and shapes, perceived typeface letters and shapes, and pencil-tapped on an fMRI-compatible tablet.Contrast maps were created from SPMs from random effects GLMs. Contrasting hand-printing letters over shapes with ink and perceiving re-presented letters over shapes indicated that L-FG, L-PC, and L-FC responded most strongly to the perceptual component of letter printing(pvoxel less than .01;pcluster less than .001). Contrasting hand-printing letters over shapes with ink and hand-printing letters over shapes without ink indicated that L-FG and R-PC responded most strongly to the motor component(pvoxel less than .01;pcluster less than .001).ROIs were defined in L-FG and R-FG by contrasting perceiving typeface letters and shapes. Comparing hand-printing forms with ink and hand-printing forms without ink revealed non-form-selective effects of the perceptual component in L-FG(tw(11)=9.76,p .001) and R-FG(tw(11)=6.56,p .001). Comparing hand-printing forms with ink and perceiving re-presentations revealed significant non-form-selective effects of the motor component in L-FG(tw(11)=4.33,p .01) and R-FG(tw(11)=5.48,p .001). Comparing hand-printing letters over shapes with ink and perceiving re-presented letters over shapes revealed a significant letter-selective effect of motor in only the L-FG(tw(5)=2.80,p .05), which is intriguing given that the R-FG responded stronger than the L-FG overall(tw(58)=8.30,p .001). Comparing hand-printing forms with no ink and pencil-tapping did not reach significance in either ROI. Results suggest that letter perception and printing are supported by similar neural systems and that the L-FG is strongly associated with visually-guided actions with letters.
Meeting abstract presented at VSS 2016
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