Language Processing Modulated by Literacy: A Network Analysis of Verbal Repetition in Literate and Illiterate Subjects

Abstract

Abstract& Previous behavioral and functional neuroimaging data indicate that certain aspects of phonological processing may not be acquired spontaneously, but are modulated by learning an alphabetic written language, that is, learning to read and write. It appears that learning an alphabetic written language modifies the auditory-verbal (spoken) language processing competence in a nontrivial way. We have previously suggested, based on behavioral and functional neuroimaging data, that auditory-verbal and written language interact not only during certain language tasks, but that learning and developing alphabetic written language capacities significantly modulates the spoken language system. Specifically, the acquisition of alphabetic orthographic knowledge has a modulatory influence on sublexical phonological processing and the awareness of sublexical phonological structure. We have suggested that developing an orthographic representation system for an alphabetic written language, and integrating a phoneme± grapheme correspondence with an existing infrastructure for auditory-verbal language processing, will result in a modified language network. Specifically, we suggest that the parallel interactive processing characteristics of the underlying language-processing brain network differ in literate and illiterate subjects. Therefore, the pattern of interactions between the regions of a suitably defined large-scale functional-anatomical network for language processing will differ between literate and illiterate subjects during certain language tasks. In order to investigate this hypothesis further, we analyzed the observed covariance structure in a PET data set from a simple auditoryverbal repetition paradigm in literate and illiterate subjects, with a network approach based on structural equation modeling (SEM). Based on a simple network model for language processing, the results of the present network analysis indicate that the network interactions during word and pseudoword repetition in the illiterate group differ, while there were no significant differences in the literate group. The differences between the two tasks in the illiterate group may reflect differences in attentional modulation of the language network, executive aspects of verbal working memory and the articulatory organization of verbal output. There were no significant differences between the literate and illiterate group during word repetition. In contrast, the network interactions differed between the literate and illiterate group during pseudoword repetition. In addition to differences similar to those observed in the illiterate group between word and pseudoword repetition, there were differences related to the interactions of the phonological loop between the groups. In particular, these differences related to the interaction between Broca's area and the inferior parietal cortex as well as the posterior-midinsula bridge between Wernicke's and Broca's area. In conclusion, the results of this network analysis are consistent with our previously pr...

Distinguishing cause from effect – many deficits associated with developmental dyslexia may be a consequence of reduced and suboptimal reading experience

“…But note that Reis and Castro-Caldas (1997) found that illiterates also performed much worse than literates on pseudoword repetition (replicated in Castro-Caldas, Petersson, Reis, Stone-Elander, & Ingvar, 1998). Petersson and colleagues have argued that this is related to an inability to handle certain aspects of sub-lexical-phonological structure (Petersson, Reis, Askelöf, Castro-Caldas, & Ingvar, 2000) and suggest that phonological representations, or the processing of these representations, are differently developed in literates and illiterates (Petersson et al, 2000cf. Smith et al, 2014).…”

Cognitive Enhancement: Methods, Ethics, Regulatory Challenges

“…In fact, conventional interventions often produce more permanent neurological changes than do drugs. Learning to read alters the way language is processed in the brain (Petersson 2000). Enriched rearing environments have been found to increase dendritic arborisation and to produce synaptic changes, neurogenesis, and improved cognition in animals (Walsh et al 1969;Greenoug and Volkmar 1973;Diamond et al 1975;Nilsson et al 1999).…”

“…The dominant cooperative framework (Buchanan et al 2001) of Western society has developed in such a way that an illiterate person is excluded from many opportunities and unable to participate in many aspects of modern life. Despite these enormous and partially coercive pressures, and despite the fact that literacy profoundly changes the way the brain processes language (Petersson 2000), literacy is not deemed to be problematic. The costs of illiteracy are placed on the individual who deliberately avoids education.…”

The irrelevant speech effect: a PET study

“…Both the insula Paulesu et al, 1993) and the basal ganglia Monchi, Petrides, Petre, Worsley, & Dagher, 2001) have also been observed in tasks involving working memory. In particular, it has been suggested that the insular cortex is an integral part of the phonological loop (Paulesu et al, 1993;Petersson, Reis, Askelof, Castro-Caldas, & Ingvar, 2000). However, the more specific functional roles of these activations as related to working memory remain unclear (for reviews, see Cabeza & Nyberg, 2000;Fletcher & Henson, 2001).…”

“…3). The superior temporal cortex, in addition to the inferior frontal (BA 44/45), supramarginal (BA 40) and the insular cortices, has been proposed to constitute the phonological loop in working memory (Paulesu et al, 1993;Petersson et al, 2000). Whether the superior temporal cortex is an integral part of the core verbal working memory network can be discussed.…”