Neurodevelopmental trajectories of letter and speech sound processing from preschool to the end of elementary school

Unraveling individual differences in learning potential: A dynamic framework for the case of reading development

“…While theoretical accounts of reading assume parallel involvement of the dorsal and ventral streams in proficient readers ( Coltheart et al, 2001 ), the ventral stream is considered particularly relevant for fluent reading of familiar/frequent words through the processing of morphological units and direct lexical access ( Pugh et al, 2001 , Yablonski et al, 2019 ). Accordingly, a developmental shift toward reliance on the ventral stream has found support in neuroimaging studies of connectivity and activity in the reading network ( Church, 2008 , Di Pietro et al, 2023 , Wise Younger et al, 2017 ).…”

“…What is common to reading acquisition in all languages is the reliance on an extended and complex brain network that with experience and maturation successively allows for efficient processing of written material ( Brem et al, 2010 , Chyl et al, 2019 , Dehaene-Lambertz et al, 2018 , Di Pietro et al, 2023 , Linkersdörfer et al, 2015 , Wang et al, 2017 , Yeatman et al, 2012a ). Unlike the network responsible for processing spoken language, which has co-evolved with humankind, reading is a recent skill in evolutionary terms and therefore cannot rely on brain structures specifically evolved for text processing.…”

“…One of the challenges in characterizing the course of functional specialization during skill learning is the observation that neural changes are often nonlinear, and not necessarily in direct alignment with the observed behavioral gains ( Dehaene-Lambertz et al, 2018 , Di Pietro et al, 2023 , Feng et al, 2022 , Fraga-González et al, 2021 , Fraga-González et al, 2022 , Huber et al, 2018 , Karipidis et al, 2021 , Romanovska et al, 2022 , Pugh et al, 2008 ). This accounts for long-term changes over months and years of learning and is also presumed to mirror changes in short-term learning as detailed below.…”

“…2 ). Brain measures reflecting functional or structural growth curves of specific components of the developing reading network instead often exhibit an inverted U-shape ( Di Pietro et al, 2023 , Fraga-González et al, 2021 , Maurer et al, 2006 , Romanovska et al, 2022 ). Similar behavioral and neural trajectories are also evident during short-term learning tasks of language and reading skills ( Guerra et al, 2023 , Hashimoto and Sakai, 2004 , Malins et al, 2021 , Mayringer and Wimmer, 2000 ; Steacy et al, 2021 ; Verwimp et al, 2023 ; Zhang et al, 2021 ).…”

“…As an example, the time-point at which letter-sound knowledge reaches the ceiling depends on the orthographic transparency and is typically achieved within a few months of schooling in orthographically shallow languages like German, Dutch, or Finnish. Lower part: schematic representation of neural activation trajectories across development, including trajectories for sensitivity to letter ( Di Pietro et al, 2023 , Fraga-González et al, 2021 ) and word or sentence processing ( Brem et al, 2009 , Dehaene-Lambertz et al, 2018 , Feng et al, 2022 , Maurer et al, 2006 , Maurer et al, 2011 , Ozernov-Palchik et al, 2022 ) reflected by the left occipito-temporal visual event-related potential N1 after around 200 ms (shown in the waveform graph at the bottom left) and vOTC activation. The dark green line represents the trajectory of the BOLD signal in the superior temporal cortex (STC) during audiovisual processing of speech sounds ( Di Pietro et al, 2023 , Romanovska et al, 2022 ).…”