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Letter production through handwriting creates visual experiences that may be important for the development of visual letter perception. We sought to better understand the neural responses to different visual percepts created during handwriting at different levels of experience. Three groups of participants, younger children, older children, and adults, ranging in age from 4.5 to 22 years old, were presented with dynamic and static presentations of their own handwritten letters, static presentations of an age-matched control's handwritten letters, and typeface letters during fMRI. First, data from each group were analyzed through a series of contrasts designed to highlight neural systems that were most sensitive to each visual experience in each age group. We found that younger children recruited ventral-temporal cortex during perception and this response was associated with the variability present in handwritten forms. Older children and adults also recruited ventral-temporal cortex; this response, however, was significant for typed letter forms but not variability. The adult response to typed letters was more distributed than in the children, including ventral-temporal, parietal, and frontal motor cortices. The adult response was also significant for one's own handwritten letters in left parietal cortex. Second, we compared responses among age groups. Compared to older children, younger children demonstrated a greater fusiform response associated with handwritten form variability. When compared to adults, younger children demonstrated a greater response to this variability in left parietal cortex. Our results suggest that the visual perception of the variability present in handwritten forms that occurs during handwriting may contribute to developmental changes in the neural systems that support letter perception., (© 2020 John Wiley & Sons Ltd.)

Studies of symbol production using fMRI often use techniques that introduce an artificial pairing between motor production and visual perception. These techniques allow participants to see their own output by recording their pen trajectories using a touchscreen-only tablet and displaying these productions on a mirror placed above their head. We recently developed an MR-safe writing tablet with video display that allows participants to see their own hand and their own productions while producing symbols in real time on the surface where they are producing them-allowing for more ecologically valid fMRI studies of production. We conducted a study to determine whether the participation of posterior parietal cortex during symbol production was affected by the pairing of motor production and visual feedback associated with the two types of tablets. We performed ROI analyses in intraparietal sulcus while adult participants produced letters to dictation using either a touchscreen-only tablet (no visual guidance of the hand) (n = 14) or using a touchscreen-and-video-display tablet (visual guidance of the hand) (n = 14). We found that left posterior intraparietal sulcus was more active during production with the touchscreen-only tablet than during production with the touchscreen-and-video-display tablet. These results suggest that posterior parietal involvement during production tasks is associated with the somewhat artificial visual-motor pairing that is introduced by the techniques used in some studies of symbol production., Competing Interests: Declaration of Competing Interest This report makes use of an MRI-compatible device that is patent pending. If a patent issues it will be owned by the Trustees of Indiana University. The authors, therefore, believe there is no conflict of interest to report., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Writing and perceiving letters are thought to share similar neural substrates; however, what constitutes a neural representation for letters is currently debated. One hypothesis is that letter representation develops from sensorimotor experience resulting in an integrated set of modality-specific regions, whereas an alternative account suggests that letter representations may be abstract, independent of modality. Studies reviewed suggest that letter representation consists of a network of modality-responsive brain regions that may include an abstract component., (Copyright © 2016 the American Physiological Society.)

Previous research has suggested that handwriting letters may be an important exerciser to facilitate early letter understanding. Experimental studies to date, however, have not investigated whether this effect is general to any visual-motor experience or specific to handwriting letters. In the present work, we addressed this issue by testing letter knowledge using three measures in preschool children before and after a school-based intervention. Participants were divided into four training groups (letter-writing, digit-writing, letter-viewing, digit-viewing) that either wrote letters or digits or viewed letters or digits, twice a week for 6 weeks. We hypothesized that the visual-motor experience of handwriting letters or digits would improve letter knowledge more than viewing experience and that this effect would not be specific to training with letters. Our results demonstrated that the writing groups improved in letter recognition--one component of letter knowledge--significantly more than the viewing groups. The letter-writing group did not improve significantly more than the digit-writing group. These results suggest that visual-motor practice with any symbol could lead to increases in letter recognition. We interpret this novel finding as suggesting that any handwriting will increase letter recognition in part because it facilitates gains in visual-motor coordination.

Handwriting is a complex visual-motor skill that affects early reading development. A large body of work has demonstrated that handwriting is supported by a widespread neural system comprising ventral-temporal, parietal, and frontal motor regions in adults. Recent work has demonstrated that this neural system is largely established by 8 years of age, suggesting that the development of this system occurs in young children who are still learning to read and write. We made use of a novel MRI-compatible writing tablet that allowed us to measure brain activation in 5–8-year-old children during handwriting. We compared activation during handwriting in children and adults to provide information concerning the developmental trajectory of the neural system that supports handwriting. We found that parietal and frontal motor involvement during handwriting in children is different from adults, suggesting that the neural system that supports handwriting changes over the course of development. Furthermore, we found that parietal and frontal motor activation correlated with a literacy composite score in our child sample, suggesting that the individual differences in the dorsal response during handwriting are related to individual differences in emerging literacy skills. Our results suggest that components of the widespread neural system supporting handwriting develop at different rates and provide insight into the mechanisms underlying the contributions of handwriting to early literacy development. [ABSTRACT FROM AUTHOR]

Complex visual–motor behaviors dominate human–environment interactions. Letter production, writing individual letters by hand, is an example of a complex visual–motor behavior composed of numerous behavioral components, including the required motor movements and the percepts that those motor movements create. By manipulating and isolating components of letter production, we provide experimental evidence that this complex visual–motor behavior is supported by a widespread neural system that is composed of smaller subsystems related to different sensorimotor components. Adult participants hand-printed letters with and without "ink" on an MR-safe digital writing tablet, perceived static and dynamic representations of their own handwritten letters, and perceived typeface letters during fMRI scanning. Our results can be summarized by three main findings: (1) Frontoparietal systems were associated with the motor component of letter production, whereas temporo-parietal systems were more associated with the visual component. (2) The more anterior regions of the left intraparietal sulcus were more associated with the motor component, whereas the more posterior regions were more associated with the visual component, with an area of visual–motor overlap in the posterior intraparietal sulcus. (3) The left posterior intraparietal sulcus and right fusiform gyrus responded similarly to both visual and motor components, and both regions also responded more during the perception of one's own handwritten letters compared with perceiving typed letters. These findings suggest that the neural systems recruited during complex visual–motor behaviors are composed of a set of interrelated sensorimotor subsystems that support the full behavior in different ways and, furthermore, that some of these subsystems can be rerecruited during passive perception in the absence of the full visual–motor behavior. [ABSTRACT FROM AUTHOR]

Handwriting letters has been shown to increase Blood Oxygen Level Dependent (BOLD) signal during letter perception in visual and motor brain regions relative to other types of training in preschool children. However, co-activation in these regions speaks neither to the presence of functional connections between them nor to the experiences by which such connections might be established. We investigated functional connectivity by applying generalized psychophysiological interactions analysis to BOLD data obtained from 4 to 6 year-old children after learning symbols through handwriting, tracing, or typing. Functional connections between (1) visual and parietal regions increased after all training conditions, (2) visual and ventral frontal regions increased after handwriting training with letters more than shapes, and (3) visual and dorsal frontal motor regions increased more after handwriting than typing letters. We conclude that visual-motor training creates functional connections among visual and motor brain regions that reflect different aspects of the handwriting experience. [ABSTRACT FROM AUTHOR]