Functional and morphological correlates of developmental dyslexia: A multimodal investigation of the ventral occipitotemporal cortex

Valentina Borghesani; Cheng Wang; Christa Watson; Florence Bouhali; Eduardo Caverzasi; Giovanni Battistella; Rian Bogley; Nicole A Yabut; Jessica Deleon; Zachary A Miller; Fumiko Hoeft; Maria Luisa Mandelli; Maria Luisa Gorno-Tempini

doi:10.1111/jon.12892

Functional and morphological correlates of developmental dyslexia: A multimodal investigation of the ventral occipitotemporal cortex

J Neuroimaging. 2021 Sep;31(5):962-972. doi: 10.1111/jon.12892. Epub 2021 Jun 11.

Authors

Valentina Borghesani¹, Cheng Wang^{1

2}, Christa Watson^{1

2}, Florence Bouhali^{3

4}, Eduardo Caverzasi^{1

2}, Giovanni Battistella^{1

2}, Rian Bogley^{1

2}, Nicole A Yabut^{1

2}, Jessica Deleon^{1

2}, Zachary A Miller^{1

2}, Fumiko Hoeft^{3

4

5

6}, Maria Luisa Mandelli^{1

2}, Maria Luisa Gorno-Tempini^{1

2

3

4}

Affiliations

¹ Department of Neurology, University of California, San Francisco, San Francisco, California, USA.
² Dyslexia Center, University of California, San Francisco, San Francisco, California, USA.
³ Department of Psychiatry and Behavioral Science, University of California, San Francisco, San Francisco, California, USA.
⁴ Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, USA.
⁵ Department of Psychological Sciences, University of Connecticut, Mansfield, Connecticut, USA.
⁶ Brain Imaging Research Center, University of Connecticut, Mansfield, Connecticut, USA.

Abstract

Background and purpose: The ventral occipitotemporal cortex (vOT) is a region crucial for reading acquisition through selective tuning to printed words. Developmental dyslexia is a disorder of reading with underlying neurobiological bases often associated with atypical neural responses to printed words. Previous studies have discovered anomalous structural development and function of the vOT in individuals with dyslexia. However, it remains unclear if or how structural abnormalities relate to functional alterations.

Methods: In this study, we acquired structural, functional (words and faces processing), and diffusion MRI data from 26 children with dyslexia (average age = 10.4 ± 2.0 years) and 14 age-matched typically developing readers (average age = 10.4 ± 1.6 years). Morphological indices of local gyrification, neurite density (i.e., dendritic arborization structure), and orientation dispersion (i.e., dendritic arborization orientation) were analyzed within the vOT region that showed preferential activation in typically developing readers for words (as compared to face stimuli).

Results: The two cohorts diverged significantly in both functional and structural measures. Compared to typically developing controls, children with dyslexia did not show selectivity for words in the left vOT (contrast: words > false fonts). This lack of tuning to printed words was associated with greater neurite dispersion heterogeneity in the dyslexia cohort, but similar neurite density. These group differences were not present in the homologous contralateral area, the right vOT.

Conclusions: Our findings provide new insight into the neurobiology of the lack of vOT word tuning in dyslexia by linking behavior, alterations in functional activation, and neurite organization.

Keywords: developmental dyslexia; diffusion MRI; functional MRI; neurite morphology; occipitotemporal cortex.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Brain Mapping
Cerebral Cortex
Child
Dyslexia* / diagnostic imaging
Humans
Magnetic Resonance Imaging*
Reading

Abstract

Publication types

MeSH terms

Grants and funding