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Left lateralization of N170 component in grapheme processing in Brazilian 8th graders and university students.
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Poster E128 in Poster Session E, Thursday, October 26, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
This poster is part of the Sandbox Series.
Marije Soto1, Diane Silva-Nasser1, Juliana Novo Gomes1, Aniela Improta França2; 1Federal University of Rio de Janeiro, Brazil, 2Universidade do. Minho, Portugal
This study zooms in on the specialization of visual processing that underlies grapheme and word form processing, and presents an ERP study comparing neurophysiological responses of 8th graders in a public state elementary school to those of university students. Participants engaged in a repetition detection task with four types of visual stimuli: words, pseudowords, false fonts and line drawings, whilst EEG signals were recorded. Of special interest was the N170 component, a neurophysiological signature sensitive to grapheme and word form processing (MAURER & McBRIDE, 2018; C, HASKO et al., 2013). Mean amplitudes from two main regions of interest (ROIs): left hemisphere occipital region (O1, PO3, PO7) and right hemisphere occipital region (O2, PO4, PO6) were analyzed applying mixed effect models with two factors (hemisphere and stimuli type). The test results indicated that, in the group of 20 young teengagers (13 to 14 y.o., fem=13) there was a clear left lateralization of print sensitive N170 responses, with significantly higher amplitudes for words and pseudowords compared to figures and false font. This results is in line with the Phonological Mapping Hypothesis according to which left lateralization occurs due to the strengthening of connections between phonological, lexical and orthographic representations stored in occipito-temporal regions, the reading process (MAURER & MCCANDLISS, 2008). Also it confirms that language with more transparent and fine grained grapheme to phoneme correspondences elicit left lateralized responses for both words and pseudowords. We also looked at individual performance of participants: stronger readers presented the highest difference between word and figure amplitudes, strongly left lateralized, whereas weaker readers did not present any difference. The varying levels of intensity and lateralization of the neurophysiological response indicate that a large portion of the participants remain in the process of obtaining reading fluency long after having started to learn how to read. Currently, data of 17 university students have been collected and analyses are underway. We expect N170 components for these putatively highly proficient readers to show the effects of lexical frequency, with higher sensitivity for words than for pseudowords, as well as a strong left lateralization of the print sensitivity. Also less variability is predicted. Overall, it seems that the qualitative correlation between performance and the degree of lateralization of the N170 component, as a reflection of the degree of specialization in grapheme processing, adequately describes and predicts reading acquisition stages, including when children are supposedly literate but still very variable in the automatization of grapheme perception. References: HASKO, S. et al. The time course of reading processes in children with and without dyslexia: an ERP study. Frontiers in human neuroscience, 7, 570. 2013. MAURER, U., McCANDLISS, B. D. The development of visual expertise for words: The contribution of electrophysiology. In E. L. Grigorenko & A. J. Naples (Eds.), New directions in communication disorders research: Integrative approaches. Single-word reading: Behavioral and biological perspectives. Mahwah, NJ, US: L.Erlbaum Associates Publishers, 2008. p. 43-63 MAURER, U.; McBRIDE, C. Neuroscience and literacy acquisition: Introduction to the special section. International Journal of Behavioral Development, 42(3), 309-310. 2018.
Topic Areas: Reading,