Pre-reading language abilities and the brain's functional reading network in young children.

Early childhood is an important period for language development that lays the foundation for future reading abilities. However, little research has focused on the functional brain systems supporting pre-reading language abilities in typically developing children. Here, we investigated functional connectivity using passive viewing functional magnetic resonance imaging (fMRI) in 50 healthy children aged 2.85-5.07 years (3.84 ​± ​0.60 years, 22 female/28 male). Children completed the NEPSY-II Phonological Processing and Speeded Naming subtests and underwent fMRI while watching a movie of their choice. Functional connectivity was measured between key brain reading areas (bilateral angular gyrus, superior temporal gyrus, and inferior frontal gyrus) and the rest of the brain. Age-adjusted pre-reading scores positively correlated with functional connectivity between (1) the right angular gyrus and superior temporal gyrus, (2) the bilateral angular gyri and right pars triangularis and motor areas, (3) the left superior temporal gyrus and bilateral medial frontal gyrus and right cerebellum, (4) the left pars triangularis and middle occipital gyrus and insula, and (5) the right pars triangularis and the bilateral thalamus. Higher pre-reading scores were associated with stronger negative functional connectivity between (1) the left angular gyrus and auditory cortex, (2) the left superior temporal gyrus and occipital vision areas, (3) the right pars triangularis and medial frontal region, and (4) the right superior temporal gyrus and the posterior cingulate/precuneus. These results suggest better integration of the reading network, as well as its connections with other brain areas that support language or reading, and more dissociation between reading areas and the default mode network, in young children with better pre-reading skills. Our findings show that relationships between functional connectivity and pre-reading language skills are evident in young children even before formal reading instruction.