Learning orthography in adulthood: A magnetoencephalographic study

Castro-Caldas, Alexandre; Nunes, Maria Vânia Silva; Maestú, Fernando; Ortiz, Tomás; Simões, Regina Helena Silva; Fernandes, Ricardo M; Guía, Elena de la; García, Eduardo; Gonçalves, M. Cardoso

doi:10.1348/174866408x289953

Cited by 16 publications

(11 citation statements)

References 48 publications

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“…This same group was studied while reading words and the areas involved were different from those used by the controls. However, in this case it was the right parietal lobe that was more active in ex-illiterate subjects (Castro-Caldas et al, 2009). This is similar to findings reported by Newman et al (2002) for the processing of American Sign Language.…”

Section: Discussionsupporting

confidence: 90%

The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

Nunes

Castro-Caldas

Rio³

et al. 2009

Dement. neuropsychol.

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The lifelong acquisition of cognitive skills shapes the biology of the brain. However, there are critical periods for the best use of the brain to process the acquired information.ObjectivesTo discuss the critical period of cognitive acquisition, the concept of cognitive reserve and the HAROLD (Hemispheric Asymmetry Reduction in Older adults) model.MethodsSeven women who learned how to read and to write after the age of 50 (ex-illiterates) and five women with 10 years of regular schooling (controls) were submitted to a language recognition test while brain activity was being recorded using magnetoencephalography. Spoken words were delivered binaurally via two plastic tubs terminating in ear inserts, and recordings were made with a whole head magnetometer consisting of 148 magnetometer coils.ResultsBoth groups performed similarly on the task of identifying target words. Analysis of the number of sources of activity in the left and right hemispheres revealed significant differences between the two groups, showing that ex-illiterate subjects exhibited less brain functional asymmetry during the language task.ConclusionsThese results should be interpreted with caution because the groups were small. However, these findings reinforce the concept that poorly educated subjects tend to use the brain for information processing in a different way to subjects with a high educational level or who were schooled at the regular time. Finally, the recruiting of both hemispheres to tackle the language recognition test occurred to a greater degree in the ex-illiterate group where this can be interpreted as a sign of difficulty performing the task.

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Section: Discussionsupporting

confidence: 90%

The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

Nunes

Castro-Caldas

Rio³

et al. 2009

Dement. neuropsychol.

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“…We propose that in temporal cortex developmental Hebbian mechanisms segregate and refine maps for object category, and we further suggest a novel consequence of category maps, namely expert processing of those clustered categories. Although adults can learn, children are better than adults at learning some things, and differences between adult and juvenile learning abilities may correlate with critical periods for the location or scale of potential neuronal plasticity (Castro-Caldas et al, 2009; Dehaene et al, 2010; Hensch, 2004; Van der Loos and Woolsey, 1973; Wiesel, 1982). …”

Section: Discussionmentioning

confidence: 99%

Behavioral and Anatomical Consequences of Early versus Late Symbol Training in Macaques

Srihasam

Mandeville

Mórocz

et al. 2012

Neuron

102

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Distinct brain regions, reproducible from one person to the next, are specialized for processing different kinds of human expertise, such as face recognition and reading. Here we explore the relationship between age of learning, learning ability, and specialized brain structures. Specifically we ask whether the existence of reproducible cortical domains necessarily means that certain abilities are innate, or innately easily learned, or whether reproducible domains can be formed, or refined, by interactions between genetic programs and common early experience. Functional MRI showed that intensive early, but not late, experience caused the formation of category-selective regions in macaque temporal lobe for stimuli never naturally encountered by monkeys. And behaviorally, early training produced more fluent processing of these stimuli than the same training in adults. One explanation for these results is that in higher cortical areas, as in early sensory areas, experience drives functional clustering and functional clustering determines how that information is processed.

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“…Indeed, comparisons of the anatomy of illiterates and literates revealed an increase of gray matter in the bilateral angular, dorsal occipital, middle temporal, and in left supramarginal and posterior superior temporal gyri (Carreiras et al 2009). As concerns white matter tracts, the only documented correlate of literacy in normal readers consists in a thickening of the splenium or the isthmus of the corpus callosum (Carreiras et al 2009;Castro-Caldas et al 2009). Such a scarcity of white matter changes may seem surprising, as one would rather expect increased anatomical connectivity between left occipito-temporal regions devoted to the processing of alphabetic strings (the Visual Word Form Area) and regions subtending phonological and semantic processes.…”

Section: Introductionmentioning

confidence: 99%

Learning to Read Improves the Structure of the Arcuate Fasciculus

Schotten¹,

et al. 2012

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The acquisition of literacy results from an effortful learning process that leads to functional changes in several cortical regions. We explored whether learning to read also leads to anatomical changes within the left intrahemispheric white matter pathways that interconnect these regions. Using diffusion tensor imaging tractography, we compared illiterates with ex-illiterates who learned to read during adulthood and literates who learned to read during their childhood. Literacy related to an increase in fractional anisotropy and a decrease in perpendicular diffusivity in the temporo-parietal portion of the left arcuate fasciculus. The microstructure within this pathway correlated with the reading performance and the degree of functional activation within 2 dominant brain regions involved in reading: The Visual Word Form Area in response to letter strings, and the posterior superior temporal cortex in response to spoken language. Thus, the acquisition of literacy is associated with a reinforcement of left temporo-parietal connections whose microstructure predicts overall reading performance and the functional specialization of the Visual Word Form Area. This anatomical magnetic resonance imaging marker may be useful to predict developmental reading disorders.

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Learning orthography in adulthood: A magnetoencephalographic study

Cited by 16 publications

References 48 publications

The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

Behavioral and Anatomical Consequences of Early versus Late Symbol Training in Macaques

Learning to Read Improves the Structure of the Arcuate Fasciculus

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