Kleinman, D. | Search bioRxiv

bioRxiv2025

Structural brain correlates of poor reading comprehension

Poor comprehenders have typical word reading skill and intelligence but poorer than expected reading comprehension. While the prevalence of poor comprehenders is similar to that of poor decoders (individuals who have difficulty fluently converting written text into spoken language), less is known about the neurobiological substrates of poor comprehension. Extant studies have found small differences in grey matter volume between poor comprehenders and poor or typically reading peers. However, a detailed quantification of cortical morphometric features and white matter integrity remains unexplored. Data from 2,100 children (1,200 with imaging data), aged 8-16 were analyzed to determine if there is a distinct neuroanatomy associated with poor reading comprehension. We computed grey matter volume, cortical thickness, and surface area, and white matter measures including mean diffusivity, fractional anisotropy, neurite orientation, and neurite density for poor comprehenders and compared to that of poor decoders and typical readers. Results revealed small but widespread white matter differences, but no grey matter differences between poor comprehenders and other readers. Poor comprehenders showed decreased white matter integrity (increased mean diffusivity, decreased neurite density) in tracts previously associated with reading, including the Superior Longitudinal Fasciculus and Inferior Longitudinal Fasciculus, and in tracts that have been associated with cognitive performance such as the Uncinate Fasciculus. These results suggest that diffuse structural connectivity differences may underlie reading comprehension weaknesses in the face of intact decoding skills. This is consistent with the behavioral profile of poor comprehenders who exhibit a broad pattern of subclinical impairments in language and integrative cognitive processes.

neuroscience↗

bioRxiv2021

The language network supports both lexical access and sentence generation during language production

A fronto-temporal brain network has long been implicated in language comprehension. However, this networks role in language production remains debated. In particular, it remains unclear whether all or only some language regions contribute to production, and which aspects of production these regions support. Across three fMRI experiments that rely on robust individual-subject analyses, we characterize the language networks response to high-level production demands. We report three novel results. First, sentence production, spoken or typed, elicits a strong response throughout the language network. Second, the language network responds to both phrase-structure building and lexical access demands, although the response to phrase-structure building is stronger and more spatially extensive, present in every language region. Finally, contra some proposals, we find no evidence of brain regions--within or outside the language network--that selectively support phrase-structure building in production relative to comprehension. Instead, all language regions respond more strongly during production than comprehension, suggesting that production incurs a greater cost for the language network. Together, these results align with the idea that language comprehension and production draw on the same knowledge representations, which are stored in a distributed manner within the language-selective network and are used to both interpret and generate linguistic utterances.

neuroscience↗