Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA.
Dev Sci. 2020 Sep;23(5):e12965. doi: 10.1111/desc.12965. Epub 2020 Apr 27.
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.
通过手写制作字母会产生视觉体验，这些体验可能对视觉字母感知的发展很重要。我们试图更好地理解在不同经验水平下手写时产生的不同视觉感知的神经反应。三个年龄组的参与者，年龄在 4.5 到 22 岁之间的年幼儿童、年长儿童和成年人，在 fMRI 期间接受了他们自己手写字母的动态和静态呈现、同龄控制者手写字母的静态呈现和字体字母的呈现。首先，通过一系列对比分析了每个组的数据，这些对比旨在突出每个年龄组中对每种视觉体验最敏感的神经系统。我们发现，年幼的儿童在感知过程中会招募腹侧颞叶皮层，而这种反应与手写形式中的可变性有关。年长的儿童和成年人也会招募腹侧颞叶皮层；然而，这种反应对于打字字母形式是显著的，但不是可变性。成人对打字字母的反应比儿童更分散，包括腹侧颞叶、顶叶和额叶运动皮层。成人对自己手写字母的反应也在左顶叶皮层中显著。其次，我们比较了年龄组之间的反应。与年长的儿童相比，年幼的儿童在与手写形式可变性相关的梭状回中表现出更大的反应。与成年人相比，年幼的儿童在左顶叶皮层中对这种可变性表现出更大的反应。我们的结果表明，在手写过程中发生的手写形式的可变性的视觉感知可能有助于支持字母感知的神经系统的发育变化。
