Reading is a multisensory task that requires the integration of visual and audio stimuli, namely printed letters and speech sounds, respectively. According to the ‘Dual-Route Model of Reading’, reading can be achieved by either the lexical route or the sublexical route (Coltheart et al., 1993). The lexical route allows us to map a word’s orthographic structure (for instance a string of letters) onto its pronunciation directly, while the sublexical route allows us to pronounce words by breaking down the word’s structure into smaller sound units and putting them together (Joubert et al., 2004).

Using brain imaging techniques like functional magnetic resonance imaging (fMRI), researchers have discovered that several areas in the left hemisphere of the brain make up the reading network (Raschle et al., 2020; Smith et al., 2018). These areas may be associated with different functions to help us read. The first area that helps us recognize letters and words is in the fusiform gyrus, also known as the visual word form area. The temporo-parietal area allows us to play with the sounds of words, and the middle temporal gyrus helps us understand the meanings of words. The inferior frontal gyrus, also known as Broca’s area, directs us to generate the sounds and meanings of words. Hence, a widespread network of brain areas is active as we read.

Through functional neuroimaging, research has also shown that the Dual-Route Model of Reading may be mapped to distinct brain areas to help us identify and read words (Roux et al., 2012). Reading via the sublexical “indirect” pathway engages the dorsal (top) areas of the brain, whereas reading via the lexical “direct” pathway involves the ventral (bottom) part of the brain (Jobard et al., 2003).

Figure 1. Dorsal and Ventral areas of the brain

In addition, research has shown that our brain uses different pathways when reading English words versus Chinese words. English is an alphabetic language, in which the sublexical pathway is used when reading regular words (e.g., brain, melt), while the lexical pathway helps us to read irregular words (e.g., pint, glove) (Wu & O’Brien, in press). In contrast, reading Chinese characters relies more on the lexical pathway as the pronunciation of a character is learnt through rote memorisation (Wu & O’Brien, in press). Overall, when reading English words, the pathway we use depends on the type of words we are reading, whereas when reading Chinese characters, we are mainly using the lexical pathway.

 

References

Coltheart, M., Curtis, B., Atkins, P., & Haller, M. (1993). Models of reading aloud: Dual-route and parallel-distributed-processing approaches. Psychological review, 100(4), 589-608. https://doi.org/10.1037/0033-295X.100.4.589   

Jobard, G., Crivello, F., & Tzourio-Mazoyer, N. (2003). Evaluation of the dual route theory of reading: a metanalysis of 35 neuroimaging studies. Neuroimage, 20(2), 693-712. https://doi.org/10.1016/S1053-8119(03)00343-4

Joubert, S., Beauregard, M., Walter, N., Bourgouin, P., Beaudoin, G., Leroux, J., Karama, S., & Lecours, A. R. (2004). Neural correlates of lexical and sublexical processes in reading. Brain and language, 89(1), 9-20. https://doi.org.remotexs.ntu.edu.sg/10.1016/S0093-934X(03)00403-6

Smith, G. J., Booth, J. R., & McNorgan, C. (2018). Longitudinal Task-Related Functional Connectivity Changes Predict Reading Development. Frontiers in psychology, 9, 1754. https://doi.org/10.3389/fpsyg.2018.01754

Raschle, N. M. R., Borbás, R. B., King, C. K., & Gaab, N. G. (2020). The Magical Art of Magnetic Resonance Imaging to Study the Reading Brain. Frontiers for Young Minds. https://kids.frontiersin.org/articles/10.3389/frym.2020.00072 

Roux, F., Durand, J., Jucla, M., Réhault, E., Reddy, M., & Démonet, J. (2012). Segregation of lexical and sub-lexical reading processes in the left perisylvian cortex. PLoS one, 7(11), e50665. https://doi.org/10.1371/journal.pone.0050665

Wu, C.-Y., & O’Brien, B. A. (In press). Brain Signatures of Reading within Different Types of Learners and across Written Languages: Evidence and Implications for Education. In D. W. L. Hung, A. Jamaludin, & A. A. Rahman (Eds.), Applying the Science of Learning to Education: An Insight into the Mechanisms that Shape Learning. Singapore: Springer Nature.

Figure 1 – https://commons.wikimedia.org/wiki/File:Ventral-dorsal_streams.svg

 

Drafted by Claire & Kah Xuan

Edited by Phoebe, Michelle & Joyce