Poster E87, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Distinct neural substrates of subcomponents of reading: Neuroimaging investigation of the Simple View of Reading framework
Ola Ozernov-Palchik1, Tracy M. Centanni2, Sara D. Beach1,3, Sidney May1, John Gabrieli1;1Massachusetts Institute of Technology, 2Texas Christian University, 3Harvard University
Reading comprehension is the overall goal of reading. The Simple View of Reading posits that reading comprehension consists of two components: decoding and language comprehension. Ample behavioral evidence supports the view that decoding and comprehension are correlated but separable skills, together accounting for a large amount of the variance in reading comprehension performance across development. Only a few studies to date have directly compared the neural underpinnings of differences in reading comprehension and single-word decoding skills during naturalistic reading in the same individuals. Adult participants (mean age: 26 years; 22 female, 21 male) were administered a comprehensive battery of 18 standardized behavioral reading, language, and cognitive measures. An exploratory factor analysis with the promax rotation technique was conducted on the measures, and four factor scores were extracted. Based on the patterns of loadings, the factors were interpreted as follows: 1) reading accuracy, 2) general cognitive, 3) decoding fluency, and 4) language comprehension. Participants then read seven paragraphs out loud in their normal reading voice and rate in a 3T MRI scanner. For the control block, participants verbally indicated whether arrows on the screen were pointing up or down (e.g., by saying “up” or “down”). Participants’ speech was recorded with an MRI-compatible microphone. fMRI analyses were conducted using FEAT in FSL, and significance was determined by Z > 2.3 and a corrected cluster significance threshold of p = 0.05. Overall, reading passages aloud activated the canonical occipitotemporal, temporoparietal, and inferior frontal reading regions, as well as superior and medial frontal regions, more strongly than did naming arrows. A series of whole-brain regressions were implemented to examine the relation between the four out-of-scanner behavioral factor scores and cortical activation for the passage > arrows contrast. (1) There were no significant clusters demonstrating correlation with the reading accuracy factor. (2) Lower scores on the general cognitive factor were associated with greater activation in bilateral thalamus, cerebellar lobules IV and V, parahippocampal and lateral occipital regions, as well as in a left temporoparietal cluster. (3) Higher scores on the decoding fluency factor were associated with greater activation in the lateral occipital gyrus, multiple temporal left hemispheric regions, and left middle/inferior frontal gyrus. (4) Finally, lower scores on the comprehension factor were associated with activity in the bilateral cingulate and several temporoparietal regions (including middle temporal, supramarginal, and angular gyri). No other correlations were significant. The neuroimaging results suggest that individual differences in decoding fluency and in language comprehension are associated with distinct patterns of activation during naturalistic reading. Therefore, these findings support the Simple View of Reading framework and provide insight into the neural mechanisms underlying the two distinct reading components and the domain-general cognitive processes operating during reading.
Themes: Reading, Disorders: Developmental
Method: Functional Imaging