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.
The acquisition of literacy transforms the human brain. By reviewing studies of illiterate subjects, we propose specific hypotheses on how the functions of core brain systems are partially reoriented or 'recycled' when learning to read. Literacy acquisition improves early visual processing and reorganizes the ventral occipito-temporal pathway: responses to written characters are increased in the left occipito-temporal sulcus, whereas responses to faces shift towards the right hemisphere. Literacy also modifies phonological coding and strengthens the functional and anatomical link between phonemic and graphemic representations. Literacy acquisition therefore provides a remarkable example of how the brain reorganizes to accommodate a novel cultural skill.
This study was aimed at examining whether pitch height and pitch change are mentally represented along spatial axes. A series of experiments explored, for isolated tones and 2-note intervals, the occurrence of effects analogous to the spatial numerical association of response codes (SNARC) effect. Response device orientation (horizontal vs. vertical), task, and musical expertise of the participants were manipulated. The pitch of isolated tones triggered the automatic activation of a vertical axis independently of musical expertise, but the contour of melodic intervals did not. By contrast, automatic associations with the horizontal axis seemed linked to music training for pitch and, to a lower extent, for intervals. These results, discussed in the light of studies on number representation, provide a new example of the effects of musical expertise on music cognition.
In two experiments, we examined the role of phonological relatedness between spoken items using both the lexical decision task and the shadowing task. In Experiment 1, words were used as primes and overlaps of zero (control), one, two, or all four or five (repetition) phonemes were compared. Except for the repetition conditions, in which facilitation was found, phonological overlap resulted in interference on word responses. These effects occurred in both tasks but were larger in lexical decision than in shadowing. The effects that were evident in shadowing can be attributed to an attentional mechanism linked to the subjects' expectancies of repetitions. The extra effects obtained in lexical decision can be interpreted by taking into account both activation of the response corresponding to the prime's lexical status and postlexical processes that check for phonological congruency between prime and target. In Experiment 2, some modifications were introduced to prevent the involvement of strategic factors, and pseudowords were used as primes. No effect at all was observed in shadowing, whereas in lexical decision interference effects occurred, which is consistent with the hypothesis that lexical decision may be negatively affected by finding a phonological discrepancy at the same time as the primed response is reactivated. Neither experiment provided evidence for the occurrence of phonological priming in the perceptual processing of words.
Learning to read requires the acquisition of an efficient visual procedure for quickly recognizing fine print. Thus, reading practice could induce a perceptual learning effect in early vision. Using functional magnetic resonance imaging (fMRI) in literate and illiterate adults, we previously demonstrated an impact of reading acquisition on both high-and low-level occipitotemporal visual areas, but could not resolve the time course of these effects. To clarify whether literacy affects early vs. late stages of visual processing, we measured event-related potentials to various categories of visual stimuli in healthy adults with variable levels of literacy, including completely illiterate subjects, early-schooled literate subjects, and subjects who learned to read in adulthood (ex-illiterates). The stimuli included written letter strings forming pseudowords, on which literacy is expected to have a major impact, as well as faces, houses, tools, checkerboards, and false fonts. To evaluate the precision with which these stimuli were encoded, we studied repetition effects by presenting the stimuli in pairs composed of repeated, mirrored, or unrelated pictures from the same category. The results indicate that reading ability is correlated with a broad enhancement of early visual processing, including increased repetition suppression, suggesting better exemplar discrimination, and increased mirror discrimination, as early as ∼100-150 ms in the left occipitotemporal region. These effects were found with letter strings and false fonts, but also were partially generalized to other visual categories. Thus, learning to read affects the magnitude, precision, and invariance of early visual processing.reading | brain plasticity | education R eading is a cultural activity in which contemporary humans have considerable training. Fluently accessing the sounds and meanings of written words requires very fast and efficient visual recognition of letter strings, at rates exceeding 100 words/ min. Neuroimaging studies have begun to show how learning to read modulates the functioning of the visual system, from early retinotopic areas (1, 2) to extrastriate occipital and temporal cortex (1, 3, 4). In particular, a restricted region of the left occipitotemporal cortex, the visual word form area (VWFA), is robustly activated when orthographic stimuli are presented to literate subjects.This VWFA activation is reproducible across participants and writing systems (5, 6), even when orthographic stimuli are flashed unconsciously (7). Orthographic processing in the VWFA is thought to be very fast, peaking at ∼170-200 ms (8-10), and is colateralized to the dominant hemisphere for language (11,12). Reading practice enhances activation of the VWFA (1, 13, 14), even in dyslexic children (15). Reading also modulates nonvisual circuits, such as the spoken language network (1,14,16,17).In addition to these positive effects of learning to read, the theory of neuronal recycling (18) proposes that literacy acquisition also may have a negative "unlearning" e...
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