Patterns of the left thalamus embedding into the connectome associated with reading skills in children with reading disabilities

Chenglin Lou; Alexandra M Cross; Lien Peters; Daniel Ansari; Marc F Joanisse

doi:10.1162/netn_a_00414

Patterns of the left thalamus embedding into the connectome associated with reading skills in children with reading disabilities

Netw Neurosci. 2024 Dec 10;8(4):1507-1528. doi: 10.1162/netn_a_00414. eCollection 2024.

Authors

Chenglin Lou^{1

2

3}, Alexandra M Cross^{3

4}, Lien Peters^{2

3

5}, Daniel Ansari^{2

3

6}, Marc F Joanisse^{2

3

7}

Affiliations

¹ Department of Special Education, Peabody College of Education, Vanderbilt University, Nashville, TN, USA.
² Department of Psychology, The University of Western Ontario, London, Canada.
³ Centre for Brain and Mind, The University of Western Ontario, London, Canada.
⁴ Health and Rehabilitation Sciences, The University of Western Ontario, London, Canada.
⁵ Faculty of Psychology and Educational Science, Department of Experimental Clinical and Health Psychology, Research in Developmental Disorder Lab, Ghent University, Ghent, Belgium.
⁶ Faculty of Education, The University of Western Ontario, London, Canada.
⁷ Haskins Laboratories, New Haven CT, USA.

Abstract

We examined how thalamocortical connectivity structure reflects children's reading performance. Diffusion-weighted MRI at 3 T and a series of reading measures were collected from 64 children (33 girls) ages 8-14 years with and without dyslexia. The topological properties of the left and right thalamus were computed based on the whole-brain white matter network and a hub-attached reading network, and were correlated with scores on several tests of children's reading and reading-related abilities. Significant correlations between topological metrics of the left thalamus and reading scores were observed only in the hub-attached reading network. Local efficiency was negatively correlated with rapid automatized naming. Transmission cost was positively correlated with phonemic decoding, and this correlation was independent of network efficiency scores; follow-up analyses further demonstrated that this effect was specific to the pulvinar and mediodorsal nuclei of the left thalamus. We validated these results using an independent dataset and demonstrated that that the relationship between thalamic connectivity and phonemic decoding was specifically robust. Overall, the results highlight the role of the left thalamus and thalamocortical network in understanding the neurocognitive bases of skilled reading and dyslexia in children.

Keywords: Connectome; DTI; Reading disabilities; Reading network; Thalamus; Topological properties.

Plain language summary

The thalamus is increasingly considered a key component of the brain’s reading network, although its precise role is less well understood. Here, we apply a network neuroscience approach to understanding how the thalamus is embedded into the reading network by examining how its wiring pattern is associated with different component aspects of reading skills in children. Using a connectome framework, we show that a local efficiency metric of the left thalamus is negatively correlated with rapid automatized naming, while its transmission cost measure is positively correlated with phonemic decoding. Connections between temporal areas of cortex and two thalamic nuclei, the pulvinar and mediodorsal thalamic nucleus, were also negatively correlated with phonemic decoding. Our result thus provides clearer specificity about how the thalamus supports reading by coordinating communications across reading network areas.