Brain sensitivity to print emerges when children learn letter–speech sound correspondences

TLDR

Reading acquisition marks a key developmental milestone, during which a new functional network forms as children link spoken sounds to unfamiliar characters, and the mature left occipito‑temporal visual word‑form system later shows print‑sensitive activation, though the timing and mechanisms of this sensitivity remain unclear. This study demonstrates the initiation of occipito‑temporal cortex sensitivity to print using fMRI and ERP in a controlled, longitudinal training study. The study used fMRI (n = 16) and ERP (n = 32) in a controlled, longitudinal training design to track the emergence of print sensitivity. Fast (<250 ms) posterior occipito‑temporal responses to print appeared alongside basic associative learning of letter‑speech sound correspondences in 6‑year‑old kindergarten children, establishing occipito‑temporal print sensitivity during the earliest phase of reading acquisition and indicating that this region first maps print and sound.

Abstract

The acquisition of reading skills is a major landmark process in a human's cognitive development. On the neural level, a new functional network develops during this time, as children typically learn to associate the well-known sounds of their spoken language with unfamiliar characters in alphabetic languages and finally access the meaning of written words, allowing for later reading. A critical component of the mature reading network located in the left occipito-temporal cortex, termed the “visual word-form system” (VWFS), exhibits print-sensitive activation in readers. When and how the sensitivity of the VWFS to print comes about remains an open question. In this study, we demonstrate the initiation of occipito-temporal cortex sensitivity to print using functional MRI (fMRI) ( n = 16) and event-related potentials (ERP) ( n = 32) in a controlled, longitudinal training study. Print sensitivity of fast (&lt;250 ms) processes in posterior occipito-temporal brain regions accompanied basic associative learning of letter–speech sound correspondences in young (mean age 6.4 ± 0.08 y) nonreading kindergarten children, as shown by concordant ERP and fMRI results. The occipito-temporal print sensitivity thus is established during the earliest phase of reading acquisition in childhood, suggesting that a crucial part of the later reading network first adopts a role in mapping print and sound.