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Investigating unique environmental contributions to the neural representation of written words: a monozygotic twin study.

Park J, Park DC, Polk TA - PLoS ONE (2012)

Bottom Line: Conflicting results have been obtained, however, perhaps because response magnitude can be influenced by other factors such as attention.The results demonstrate significantly greater effects of unique environment in the word and pseudoword conditions compared to the consonant string and false font conditions both in VWFA and in left striate cortex.These findings provide direct evidence for environmental contributions to the neural architecture for reading, and suggest that learning phonology and/or orthographic patterns plays the biggest role in shaping that architecture.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America. Joonkoo.park@duke.edu

ABSTRACT
The visual word form area (VWFA) is a region of left inferior occipitotemporal cortex that is critically involved in visual word recognition. Previous studies have investigated whether and how experience shapes the functional characteristics of VWFA by comparing neural response magnitude in response to words and nonwords. Conflicting results have been obtained, however, perhaps because response magnitude can be influenced by other factors such as attention. In this study, we measured neural activity in monozygotic twins, using functional magnetic resonance imaging. This allowed us to quantify differences in unique environmental contributions to neural activation evoked by words, pseudowords, consonant strings, and false fonts in the VWFA and striate cortex. The results demonstrate significantly greater effects of unique environment in the word and pseudoword conditions compared to the consonant string and false font conditions both in VWFA and in left striate cortex. These findings provide direct evidence for environmental contributions to the neural architecture for reading, and suggest that learning phonology and/or orthographic patterns plays the biggest role in shaping that architecture.

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Related in: MedlinePlus

The mean response magnitude in the VWFA.Error bars represent standard error across all participants.
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pone-0031512-g003: The mean response magnitude in the VWFA.Error bars represent standard error across all participants.

Mentions: Parameter estimates for the WD, PW, CS, and FF conditions from odd runs within each ROI were computed for each participant. Then, the mean parameter estimate in each condition was computed across all participants (see Fig. 3 and Fig. S1) and used as the primary dependent measure. In order to quantify the effect of unique environment, the ICC between MZ twins was computed (see Fig. 4). First, linear effects of age and sex were removed from the parameter estimates to remove any variance explained by these covariates (i.e., the residuals from a regression model including age and sex as regressors were treated as the measure of interest in the MZ correlation analysis). Then, the ICC across MZ twins of the mean parameter estimate for each condition was computed [21]. To enable comparison between different correlation estimates, the computed ICC underwent Fisher's r-to-z transformation. The MZ correlation (or MZ ICC) reported in this paper refers to z-transformed ICC. ICCWD, ICCPW, ICCCS, and ICCFF refer to ICC estimates in each of the four conditions.


Investigating unique environmental contributions to the neural representation of written words: a monozygotic twin study.

Park J, Park DC, Polk TA - PLoS ONE (2012)

The mean response magnitude in the VWFA.Error bars represent standard error across all participants.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3275550&req=5

pone-0031512-g003: The mean response magnitude in the VWFA.Error bars represent standard error across all participants.
Mentions: Parameter estimates for the WD, PW, CS, and FF conditions from odd runs within each ROI were computed for each participant. Then, the mean parameter estimate in each condition was computed across all participants (see Fig. 3 and Fig. S1) and used as the primary dependent measure. In order to quantify the effect of unique environment, the ICC between MZ twins was computed (see Fig. 4). First, linear effects of age and sex were removed from the parameter estimates to remove any variance explained by these covariates (i.e., the residuals from a regression model including age and sex as regressors were treated as the measure of interest in the MZ correlation analysis). Then, the ICC across MZ twins of the mean parameter estimate for each condition was computed [21]. To enable comparison between different correlation estimates, the computed ICC underwent Fisher's r-to-z transformation. The MZ correlation (or MZ ICC) reported in this paper refers to z-transformed ICC. ICCWD, ICCPW, ICCCS, and ICCFF refer to ICC estimates in each of the four conditions.

Bottom Line: Conflicting results have been obtained, however, perhaps because response magnitude can be influenced by other factors such as attention.The results demonstrate significantly greater effects of unique environment in the word and pseudoword conditions compared to the consonant string and false font conditions both in VWFA and in left striate cortex.These findings provide direct evidence for environmental contributions to the neural architecture for reading, and suggest that learning phonology and/or orthographic patterns plays the biggest role in shaping that architecture.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America. Joonkoo.park@duke.edu

ABSTRACT
The visual word form area (VWFA) is a region of left inferior occipitotemporal cortex that is critically involved in visual word recognition. Previous studies have investigated whether and how experience shapes the functional characteristics of VWFA by comparing neural response magnitude in response to words and nonwords. Conflicting results have been obtained, however, perhaps because response magnitude can be influenced by other factors such as attention. In this study, we measured neural activity in monozygotic twins, using functional magnetic resonance imaging. This allowed us to quantify differences in unique environmental contributions to neural activation evoked by words, pseudowords, consonant strings, and false fonts in the VWFA and striate cortex. The results demonstrate significantly greater effects of unique environment in the word and pseudoword conditions compared to the consonant string and false font conditions both in VWFA and in left striate cortex. These findings provide direct evidence for environmental contributions to the neural architecture for reading, and suggest that learning phonology and/or orthographic patterns plays the biggest role in shaping that architecture.

Show MeSH
Related in: MedlinePlus