Perceptual and motor effects of letter writing on brain regions associated with letter perception<br /> 

Writing individual letters, or letter writing, is a complicated behavior that requires the coordination of several neural systems—particularly visual and motor systems. Handwriting is especially effective at increasing letter recognition abilities in preliterate children and its effectiveness is, to some extent, due to the visual percepts created during letter writing. We investigated the contribution of visual and motor brain systems during letter writing and the response of these brain systems to the different visual percepts created. Fourteen right-handed literate adults were asked to write letters with and without ink, perceive static and dynamic re-presentations of their own handwritten letters, and perceive typeface letters. Whole brain contrasts were conducted to determine regions within the resulting letter writing network that were preferentially involved in either the visual or motor aspect of handwriting. ROI analyses were conducted to determine the sensitivity of these regions to the different visual experiences associated with letter writing (e.g., seeing your own handwritten letter). We found that the visual component of letter writing is most associated with the left fusiform gyrus (L FuG), right intraparietal sulcus (R IPS), and right superior parietal lobe (R SPL) whereas the motor component of letter writing was most associated with the left frontal motor cortex and the left superior parietal lobule. The ROI analyses revealed that both visual and motor components localized to the L FuG and L dorsal precentral gyrus, respectively, respond greater during the perception of one’s own handwritten letter when compared to a typed letter. Additionally, regions in IPS that prefer one’s own handwritten letters to typed letters and regions in FuG that prefer typed letters to fixation both respond strongest during the full act of letter writing when compared to any of its sub-components. We conclude that the visual and motor systems involved during letter writing respond preferentially to the visual percepts created during letter writing, indicating a link between the neural systems supporting letter writing and letter perception.