How words and space collide: Lexical and sublexical reading are reliant on separable reflexive and voluntary attention regions in hybrid tasks

What's in a game: Video game visual-spatial demand location exhibits a double dissociation with reading speed

This research sought to clarify the nature of the relationship between video game experience, attention, and reading. Previous studies have suggested playing action video games can improve reading ability in children with dyslexia. Other research has linked video game experience with visual-spatial attention, and visual-spatial attention with reading. We hypothesized that the visual-spatial demands of video games may drive relationships with reading through attentional processing. In this experiment we used a hybrid attention/reading task to explore the relationship between video game visual-spatial demands, reading and attention. We also developed novel visual-spatial demand measures using participants' top five played video games for an individual-specific measure of visual demands. Peripheral visual demands in video games were associated with faster reading times, while central visual demands were associated with slower reading times for both phonetic decoding and lexical reading. In addition, video game experience in terms of hours spent playing video games each week interacted with the cueing effect size in the lexical reading condition, with experienced video game players exhibiting a larger cueing effect than participants with less video game experience. These results suggest that exposure to peripheral visual spatial demands in video games may be related to both lexical and sublexical reading processes in hybrid attentional reading tasks such as ours with skilled adult readers, which has implications not only for models of how ventral and dorsal stream reading and visual-spatial attention are integrated, but also for the development of dyslexia diagnostics and remediation.

Functional neuroanatomy of reading in Czech: Evidence of a dual-route processing architecture in a shallow orthography

Introduction

According to the strong version of the orthographic depth hypothesis, in languages with transparent letter-sound mappings (shallow orthographies) the reading of both familiar words and unfamiliar nonwords may be accomplished by a sublexical pathway that relies on serial grapheme-to-phoneme conversion. However, in languages such as English characterized by inconsistent letter-sound relationships (deep orthographies), word reading is mediated by a lexical-semantic pathway that relies on mappings between word-specific orthographic, semantic, and phonological representations, whereas the sublexical pathway is used primarily to read nonwords.

Methods

In this study, we used functional magnetic resonance imaging to elucidate neural substrates of reading in Czech, a language characterized by a shallo worthography. Specifically, we contrasted patterns of brain activation and connectivity during word and nonword reading to determine whether similar or different neural mechanisms are involved. Neural correlates were measured as differences in simple whole-brain voxel-wise activation, and differences in visual word form area (VWFA) task-related connectivity were computed on the group level from data of 24 young subject. Trial-to-trial reading reaction times were used as a measure of task difficulty, and these effects were subtracted from the activation and connectivity effects in order to eliminate difference in cognitive effort which is naturally higher for nonwords and may mask the true lexicality effects.

Results

We observed pattern of activity well described in the literature mostly derived from data of English speakers - nonword reading (as compared to word reading) activated the sublexical pathway to a greater extent whereas word reading was associated with greater activation of semantic networks. VWFA connectivity analysis also revealed stronger connectivity to a component of the sublexical pathway - left inferior frontal gyrus (IFG), for nonword compared to word reading.

Discussion

These converging results suggest that the brain mechanism of skilled reading in shallow orthography languages are similar to those engaged when reading in languages with a deep orthography and are supported by a universal dual-pathway neural architecture.

The effects of bilateral posterior parietal cortex tRNS on reading performance

According to established cognitive neuroscience knowledge based on studies on disabled and typically developing readers, reading is based on a dual-stream model in which a phonological-dorsal stream (left temporo-parietal and inferior frontal areas) processes unfamiliar words and pseudowords, whereas an orthographic-ventral stream (left occipito-temporal and inferior frontal areas) processes known words. However, correlational neuroimaging, causal longitudinal, training, and pharmacological studies have suggested the critical role of visuo-spatial attention in reading development. In a double blind, crossover within-subjects experiment, we manipulated the neuromodulatory effect of a short-term bilateral stimulation of posterior parietal cortex (PPC) by using active and sham tRNS during reading tasks in a large sample of young adults. In contrast to the dual-stream model predicting either no effect or a selective effect on the stimulated phonological-dorsal stream (as well as to a general multisensory effect on both reading streams), we found that only word-reading performance improved after active bilateral PPC tRNS. These findings demonstrate a direct neural connectivity between the PPC, controlling visuo-spatial attention, and the ventral stream for visual word recognition. These results support a neurobiological model of reading where performance of the orthographic-ventral stream is boosted by an efficient deployment of visuo-spatial attention from bilateral PPC stimulation.

Structural connectivity predicts functional activation during lexical and sublexical reading

A critical question in neuroscience is the extent to which structural connectivity of the brain predicts localization of brain function. Recent research has suggested that anatomical connectivity can predict functional magnetic resonance imaging (fMRI) responses in several cognitive domains, including face, object, scene, and body processing, and development of word recognition skills (Osher et al., 2016; Saygin et al., 2016). However, this technique has not yet been extended to skilled word reading. Thus, we developed a computational model that relates anatomical connectivity (measured using probabilistic tractography) of individual cortical voxels to fMRI responses of the same voxels during lexical and sublexical reading tasks. Our results showed that the model built from structural connectivity was able to accurately predict functional responses of individual subjects based on their structural connectivity alone. This finding was apparent across the cortex, as well as to specific regions of interest associated with reading, language, and spatial attention. Further, we identified the structural connectivity networks associated with different aspects of skilled reading using connectivity analyses, and showed that interconnectivity between left hemisphere language and right hemisphere attentional areas underlies both lexical and sublexical reading. This work has important implications for understanding how structural connectivity contributes to reading and suggests that there is a relationship between skilled reading and neuroanatomical brain connectivity that future research should continue to explore.