The cerebral lateralization of written language has received very limited research attention in comparison to the wealth of studies on the cerebral lateralization of oral language. The purpose of the present study was thus to further our understanding of written language lateralization, by elucidating on the relative contribution of language and motor areas. This was achieved by comparing written word generation with a writing task that has similar visuomotor demands, but does not include language (i.e., the repeated drawing of symbols). We assessed cerebral laterality in 54 left- and right-handed participants by means of functional transcranial Doppler ultrasound (fTCD), a non-invasive, perfusion-sensitive neuroimaging technique. Our findings suggest that, in right-handers, the linguistic aspect of the written word generation task recruited left-hemispheric areas during writing, similarly to oral language production. In left-handers, we failed to observe the same effect, possibly due to the great variability in cerebral laterality patterns within this group or alternatively due to the attentional demands of the symbol copying task. Future work could investigate such demands using both simple and complex stimuli in the copying condition.
bioRxiv Subject Collection: Neuroscience