Thalamus is a common locus of reading, arithmetic, and IQ: Analysis of local intrinsic functional properties

• Published in: Brain and language Vol. 209; p. 104835
• Main Authors: Koyama, Maki S., Molfese, Peter J., Milham, Michael P., Mencl, W. Einar, Pugh, Kenneth R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.10.2020; Academic Press
• Subjects: Arithmetic; Attention; Brain; Brain - diagnostic imaging; Brain - physiology; Brain Mapping - methods; Common latent factor; Female; Fractional amplitude of low frequency fluctuations; Functional magnetic resonance imaging; Humans; Individual differences; Intelligence; Intelligence - physiology; Magnetic Resonance Imaging - methods; Male; Mathematical Concepts; Mathematics; Medical imaging; Parietal Lobe - diagnostic imaging; Parietal Lobe - physiology; Reading; Reading achievement; Regional homogeneity; Resting-state fMRI; Selective attention; Skills; Thalamus; Thalamus - diagnostic imaging; Thalamus - physiology; Young Adult; Young adults; Selective attention; Reading; Common latent factor; Regional homogeneity; IQ; Resting-state fMRI; Thalamus; Arithmetic; Fractional amplitude of low frequency fluctuations
• ISSN: 0093-934X; 1090-2155
• DOI: 10.1016/j.bandl.2020.104835

•Models simultaneously examine achievement (reading, arithmetic) and IQ measures; not covary out IQ as a nuisance variable.•ReHo and fALFF are used to examine local intrinsic functional connectivity and activity, respectively.•Higher ReHo in thalamus/pulvinar is associated with lower performance on all three measures (reading, arithmetic, and IQ).•Higher fALFF in the left superior parietal lobule is associated with higher word reading and IQ. Neuroimaging studies of basic achievement skills – reading and arithmetic – often control for the effect of IQ to identify unique neural correlates of each skill. This may underestimate possible effects of common factors between achievement and IQ measures on neuroimaging results. Here, we simultaneously examined achievement (reading and arithmetic) and IQ measures in young adults, aiming to identify MRI correlates of their common factors. Resting-state fMRI (rs-fMRI) data were analyzed using two metrics assessing local intrinsic functional properties; regional homogeneity (ReHo) and fractional amplitude low frequency fluctuation (fALFF), measuring local intrinsic functional connectivity and intrinsic functional activity, respectively. ReHo highlighted the thalamus/pulvinar (a subcortical region implied for selective attention) as a common locus for both achievement skills and IQ. More specifically, the higher the ReHo values, the lower the achievement and IQ scores. For fALFF, the left superior parietal lobule, part of the dorsal attention network, was positively associated with reading and IQ. Collectively, our results highlight attention-related regions, particularly the thalamus/pulvinar as a key region related to individual differences in performance on all the three measures. ReHo in the thalamus/pulvinar may serve as a tool to examine brain mechanisms underlying a comorbidity of reading and arithmetic difficulties, which could co-occur with weakness in general intellectual abilities.