Brain development from sensorimotor experiences: Handwriting and letter perception

Abstract

Handwriting is a visual-motor activity that is particularly effective at increasing letter recognition, a fundamental skill in early reading development. This dissertation focuses on understanding the neural mechanisms that underlie increases in letter recognition after handwriting practice. The hypotheses of this dissertation are that (1) the visual-motor coordination inherent to handwriting letters contributes to the emergence of coordinated neural activity among visual and motor brain systems during letter perception and that (2) the emergence of this visual-motor functional connectivity during perception translates to gains in visual letter recognition. In the first and second studies, I demonstrate that visual-motor functional connectivity supports handwriting in literate adults and that handwriting practice leads to a similar neural response during letter perception in preliterate children. In the third study, I demonstrate that the neural systems supporting letter perception in literate children primarily incorporate the visual system while those that support letter perception in adults incorporate both visual and motor systems. In the final study, I demonstrate that the contingency between the motor experience of handwriting and the visual experience of the letter as it is being produced contributes to increases in letter recognition with a temporary increase in visual-motor functional connectivity. These studies suggest, collectively, that one way that handwriting increases letter recognition is by establishing functional pathways among visual and motor brain systems that facilitate the influence of both visual and motor information during recognition. This research suggests, more broadly, that actions that tightly couple visual and motor systems are supported by functional connections that mold the neural mechanisms underlying object recognition.