Biological abnormality of impaired reading is constrained by culture

Abstract

Developmental dyslexia is characterized by a severe reading problem in people who have normal intelligence and schooling. Impaired reading of alphabetic scripts is associated with dysfunction of left temporoparietal brain regions. These regions perform phonemic analysis and conversion of written symbols to phonological units of speech (grapheme-to-phoneme conversion); two central cognitive processes that mediate reading acquisition. Furthermore, it has been assumed that, in contrast to cultural diversities, dyslexia in different languages has a universal biological origin. Here we show using functional magnetic resonance imaging with reading-impaired Chinese children and associated controls, that functional disruption of the left middle frontal gyrus is associated with impaired reading of the Chinese language (a logographic rather than alphabetic writing system). Reading impairment in Chinese is manifested by two deficits: one relating to the conversion of graphic form (orthography) to syllable, and the other concerning orthography-to-semantics mapping. Both of these processes are critically mediated by the left middle frontal gyrus, which functions as a centre for fluent Chinese reading that coordinates and integrates various information about written characters in verbal and spatial working memory. This finding provides an insight into the fundamental pathophysiology of dyslexia by suggesting that rather than having a universal origin, the biological abnormality of impaired reading is dependent on culture.

Arithmetic processing in the brain shaped by cultures

“…Whereas previous neuroimaging studies have revealed differential activation patterns during reading processes (e.g., the temporal-parietal regions being activated in NES but the middle frontal gyrus in NCS), the question remains whether these differences are derived from culture characteristics rather than ethnic or hereditary factors (1,9). We hypothesize that number representation and arithmetic processing in the brain may be affected by a variety of cultural factors such as educational systems and mathematics learning strategies that are beyond language-related experiences.…”

“…By filling the blank with ''7,'' indicating an identical output along with the same visual input, this raises an interesting experimental question: are the underlying brain processes different between these two students? So far there has been little work directly addressing this issue, although previous studies implicated culture constraints on the brain processing of reading (1)(2)(3). The involvement of numbers in mental calculation has been associated with language processing as proposed by Dehaene and others (4)(5)(6)(7)(8).…”

Developmental dyslexia: an update

“…This region may be involved in analyzing the written word. However, this cannot be a universal theory because there is no deficit in the posterior-temporal brain region in Chinese dyslexic patients (Siok et al 2004;Ziegler 2006). Instead, there is a functional disruption of the left middle frontal gyrus.…”

Object words modulate the activity of the mirror neuron system during action imitation

“…The MFG, as previous studies have indicated, is a well‐known key part of the Chinese word processing brain network (Liu et al., 2006; Siok, Perfetti, Jin, & Tan, 2004). For example, it has been proposed as an area involving in the integration of visual orthographic information with phonology in Chinese (Tan, Laird, Li, & Fox, 2005).…”