Does literacy improve brain function? Does it also entail losses? Using functional magnetic resonance imaging, we measured brain responses to spoken and written language, visual faces, houses, tools, and checkers in adults of variable literacy (10 were illiterate, 22 became literate as adults, and 31 were literate in childhood). As literacy enhanced the left fusiform activation evoked by writing, it induced a small competition with faces at this location, but also broadly enhanced visual responses in fusiform and occipital cortex, extending to area V1. Literacy also enhanced phonological activation to speech in the planum temporale and afforded a top-down activation of orthography from spoken inputs. Most changes occurred even when literacy was acquired in adulthood, emphasizing that both childhood and adult education can profoundly refine cortical organization.

Do the neural circuits for reading vary across culture? Reading of visually complex writing systems such as Chinese has been proposed to rely on areas outside the classical left-hemisphere network for alphabetic reading. Here, however, we show that, once potential confounds in cross-cultural comparisons are controlled for by presenting handwritten stimuli to both Chinese and French readers, the underlying network for visual word recognition may be more universal than previously suspected. Using functional magnetic resonance imaging in a semantic task with words written in cursive font, we demonstrate that two universal circuits, a shape recognition system (reading by eye) and a gesture recognition system (reading by hand), are similarly activated and show identical patterns of activation and repetition priming in the two language groups. These activations cover most of the brain regions previously associated with culture-specific tuning. Our results point to an extended reading network that invariably comprises the occipitotemporal visual wordform system, which is sensitive to well-formed static letter strings, and a distinct left premotor region, Exner's area, which is sensitive to the forward or backward direction with which cursive letters are dynamically presented. These findings suggest that cultural effects in reading merely modulate a fixed set of invariant macroscopic brain circuits, depending on surface features of orthographies.cross-cultural invariance | functional magnetic resonance imaging | neuronal recycling | masked priming A pproximately one-fifth of today's world population is still unable to read and write (1). The acquisition of written language does not rely on a specific innate ability but is an education-dependent skill resulting from the learning of mapping rules linking written codes, speech sounds, and word meanings. At the neural level, literacy acquisition imposes various structural and functional changes to the human brain, particularly in the visual cortex where responses become attuned to a specific script, but also in other areas of the temporal and parietal lobes (2, 3).The issue that we raise here is whether those changes vary considerably from one culture to another or whether they consistently engage a universal and largely invariant brain network. Past research indicated that skilled reading universally relies on a posterior left-hemisphere network, including the lateral occipitotemporal visual word-form area (VWFA) for perceptual analysis of written words (4, 5), the inferior parietal and superior temporal cortices involved in print-to-sound translation (6, 7), and lateral temporal cortices involved in access to word meaning (8-10). Reading of alphabetic scripts engages this multicomponent system with only small cultural variation depending on the degree of transparency (11) and grain size (12) of the orthographic system. However, beyond this shared left posterior network, several previous studies with normal (8,13,14) and dyslexic (15, 16) Chinese participants defended a cu...