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Summaries of recent research on reading and word recognition.
Livia
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- June 22, 2011
- 05:24 AM
- 558 views
N1 Specialization in Children with Dyslexia
by Livia in Reading and Word Recognition Research
Accessibility: Advanced
It's been a little while, but we've been talking about the N1 component and how it relates to reading. Just to recap, the N1 component is an ERP component occurring at around 170 ms. In normal reading adults, the component is stronger for words than for symbols. We will refer to the words minus symbols difference as “N1 specialization for words .” Pre-reading kindergartners do not have this N1 specialization, while second graders have a stronger N1 specialization compared to adults. Today we focus on children with dyslexia.
As you might've guessed, Maurer and colleagues did the same experiment on children with dyslexia as well (see previous article for more information on what they did). These are the findings:
1. N1 specialization for words over symbols was much reduced in dyslexic second graders compared to normal reading second graders.
2. N1 specialization correlated with reading speed in second graders.
3. Interestingly, although dyslexic second graders had reduced specialization, they actually had a greater specialization two years earlier (in kindergarten) than their normal reading counterparts. I'm not quite sure why this would be.
4. In addition to the N1 difference, there was also a reduced response in the earlier P1 component in children with dyslexia (at both ages – kindergarten and second grade). This reduction was general for both words and symbols though, and not specialized to words.
Maurer U, Brem S, Bucher K, Kranz F, Benz R, Steinhausen HC, & Brandeis D (2007). Impaired tuning of a fast occipito-temporal response for print in dyslexic children learning to read. Brain : a journal of neurology, 130 (Pt 12), 3200-10 PMID: 17728359What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Maurer U, Brem S, Bucher K, Kranz F, Benz R, Steinhausen HC, & Brandeis D. (2007) Impaired tuning of a fast occipito-temporal response for print in dyslexic children learning to read. Brain : a journal of neurology, 130(Pt 12), 3200-10. PMID: 17728359
- June 22, 2011
- 05:24 AM
- 566 views
N1 Specialization in Children with Dyslexia
by Livia in Reading and Word Recognition Research
Accessibility: Advanced
It's been a little while, but we've been talking about the N1 component and how it relates to reading. Just to recap, the N1 component is an ERP component occurring at around 170 ms. In normal reading adults, the component is stronger for words than for symbols. We will refer to the words minus symbols difference as “N1 specialization for words .” Pre-reading kindergartners do not have this N1 specialization, while second graders have a stronger N1 specialization compared to adults. Today we focus on children with dyslexia.
As you might've guessed, Maurer and colleagues did the same experiment on children with dyslexia as well (see previous article for more information on what they did). These are the findings:
1. N1 specialization for words over symbols was much reduced in dyslexic second graders compared to normal reading second graders.
2. N1 specialization correlated with reading speed in second graders.
3. Interestingly, although dyslexic second graders had reduced specialization, they actually had a greater specialization two years earlier (in kindergarten) than their normal reading counterparts. I'm not quite sure why this would be.
4. In addition to the N1 difference, there was also a reduced response in the earlier P1 component in children with dyslexia (at both ages – kindergarten and second grade). This reduction was general for both words and symbols though, and not specialized to words.
Maurer U, Brem S, Bucher K, Kranz F, Benz R, Steinhausen HC, & Brandeis D (2007). Impaired tuning of a fast occipito-temporal response for print in dyslexic children learning to read. Brain : a journal of neurology, 130 (Pt 12), 3200-10 PMID: 17728359What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Maurer U, Brem S, Bucher K, Kranz F, Benz R, Steinhausen HC, & Brandeis D. (2007) Impaired tuning of a fast occipito-temporal response for print in dyslexic children learning to read. Brain : a journal of neurology, 130(Pt 12), 3200-10. PMID: 17728359
- April 12, 2011
- 03:31 PM
- 558 views
The N1 Component in Second Graders
by Livia in Reading and Word Recognition Research
Accessibility: Advanced
Last week, we learned that the N1 component in normal reading adults differentiated between words and symbols, while the N1 component in pre-reading kindergartners did not. The question now is, at what point in development does N1 component start resembling that of adults? Maurer and colleagues tested the same kindergartners from their 2005 paper when the kids were in second grade to see how their brain activity changed after two years of reading instruction.
These were their findings:
1. The N1 component differentiates between words and simple strings in the second graders.
2. Second graders actually had a greater words/symbols N1 difference than adults.*
3. There is a correlation between N1 specialization and reading fluency. In other words, the difference in N1 amplitude between words and symbols was correlated with faster reading in the second graders.
4. The N1 negativity was more left lateralized in adults than in children. The N1 topography was bilateral for 2nd graders, and right lateralized in kindergareners.
Conclusions: Two years of reading instruction is enough for the brain to start differentiating between words and meaningless symbols. In terms of the development of N1 specialization, there are hints of a U shaped curve, with 2nd graders displaying even greater word/symbol differences than adults.
* Amplitudes in general were bigger in the second graders, but the difference held when amplitudes were normalized between children and adults
Maurer U, Brem S, Kranz F, Bucher K, Benz R, Halder P, Steinhausen HC, & Brandeis D (2006). Coarse neural tuning for print peaks when children learn to read. NeuroImage, 33 (2), 749-58 PMID: 16920367
What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Maurer U, Brem S, Kranz F, Bucher K, Benz R, Halder P, Steinhausen HC, & Brandeis D. (2006) Coarse neural tuning for print peaks when children learn to read. NeuroImage, 33(2), 749-58. PMID: 16920367
- April 8, 2011
- 11:10 AM
- 649 views
The N1 Component in Prereading Children
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
Just to recap from the last article, the N170 is an ERP component that differentiates between words and symbol strings in normal reading adults. This the specialization developed after learning to read, or does it have something to do with the visual properties of symbols?
Maurer and colleagues tested pre-reading kindergartners to see whether the specialization is there before they learn to read. They had kids perform the same task as adults (looking at a series of words, pseudowords, symbol strings, and pictures).
They found several things:
1. Adults again had the same N170 (called N1 in this paper), which was stronger for words than symbols.
2. Kids also had an N1, but it was later, had a larger amplitude, and most importantly, did not distinguish between words and symbols, suggesting that this N1 specialization stems from experience with words.
3. Some of the kids, the ones with high letter knowledge, did have an N1 that differentiated between letters and symbols. However, the pattern was different from adults. While adults had the strongest effect on the left side of the brain, these children showed an effect on the right side.
So in conclusion, the N1 specialization seems to be related to reading. However, there seem to be some intermediate steps in the development of the specialization. At least in an early stage, the right hemisphere is involved, and then the processing becomes more left lateralized.
Maurer U, Brem S, Bucher K, & Brandeis D (2005). Emerging neurophysiological specialization for letter strings. Journal of cognitive neuroscience, 17 (10), 1532-52 PMID: 16269095
What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Maurer U, Brem S, Bucher K, & Brandeis D. (2005) Emerging neurophysiological specialization for letter strings. Journal of cognitive neuroscience, 17(10), 1532-52. PMID: 16269095
- April 7, 2011
- 03:13 PM
- 614 views
Introduction to the N170 Response to Words
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
This month is N170 month. I'm going to be going through a bunch of papers by Urs Maurer on the N170 ERP component and how it relates to word processing. EEG is not my specialty, so hopefully I won't mess anything up.
For this post, we'll start with the basics. The N170 is an ERP component measured in EEG experiments. The N means that it is a negative potential, and the 170 means that it peaks roughly at around 170 ms, although the timing can vary. The N170 tends to be elicited by certain categories of visual images (like faces), and is enhanced for categories for which the subject has some expertise (for example, enhanced N170 response for bird experts when viewing birds).
This last characteristic makes the N170 helpful for studying word processing. Urs Maurer and colleagues tested adults by showing them words, pseudowords, and symbol strings*. The adults showed a greater N170 to words than symbol strings, which would be consistent with an expertise for words acquired over years of reading. The N170 was also more left lateralized for words than to symbol strings, which is not surprising given the general left lateralization of language. Also, the N170 seems to be stronger over the inferior occipital temporal channels, close to the visual word form area.
So those are the basics for the N170 in normal reading adults. It's a useful tool for studying word processing in populations like children and people with dyslexia, so that is where we will continue.
*the task was to detect repetitions
Maurer U, Brandeis D, & McCandliss BD (2005). Fast, visual specialization for reading in English revealed by the topography of the N170 ERP response. Behavioral and brain functions : BBF, 1 PMID: 16091138
What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Maurer U, Brandeis D, & McCandliss BD. (2005) Fast, visual specialization for reading in English revealed by the topography of the N170 ERP response. Behavioral and brain functions : BBF, 13. PMID: 16091138
- February 27, 2011
- 11:13 PM
- 398 views
Brain Measures Predict Future Improvement in Children With Dyslexia
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate
Disclaimer: My PI is an author on this paper.
There is a lot of variability in outcomes for children diagnosed with dyslexia. Some children improve greatly over time, while others don't. Today, we're looking at a paper that asks whether it's possible to predict improvement in children with dyslexia.
Fumiko Hoeft and colleagues scanned children with and without dyslexia while performing a word rhyme task. They also tested the children on several reading measures. Two and half years later, they retested the children again on the same reading measures. Some of the children improved, while others didn't . The question then, is whether there is something from the brain scans or test scores in the first session that can predict performance 2 1/2 years later.
The researchers found two brain measures that predicted improvement in reading skills: greater white matter integrity in the right superior longitudinal fasciculus, and activation in the right inferior frontal gyrus during the rhyming task. Note that these regions are not your typical language regions. In fact, they are the right hemisphere counterparts of language processing regions in typical readers. Also, these didn’t correlate with reading improvement in control readers.This suggests that rather than imitating what typical readers are doing, the dyslexics who improve are bringing in compensatory mechanisms.
So if we have a dyslexic child, how accurately can we predict future improvement? The researchers found that brain data from those two regions by themselves predicted reading gains with 72% accuracy. When the researchers used data from the entire brain, they predicted reading gains with 90% accuracy. (Chance would be 50%. The researchers were trying to predict whether a child’s improvement was below or above the median improvement for the entire group.)
These results are an interesting case of brain data giving us more information the behavioral measures. None of the behavioral measures predicted which children will greet could improve, but the brain data did.
One might ask how useful these results would be for dyslexics. On the one hand, any information is helpful. On the other, if you are in the group predicted to not show improvements, would you really want to know? One good thing about this type of research is that perhaps if we keep going in this direction, we might be able to not only predict improvement, but predict improvement to different types of interventions, thus leading to better treatment.
Hoeft F, McCandliss BD, Black JM, Gantman A, Zakerani N, Hulme C, Lyytinen H, Whitfield-Gabrieli S, Glover GH, Reiss AL, & Gabrieli JD (2011). Neural systems predicting long-term outcome in dyslexia. Proceedings of the National Academy of Sciences of the United States of America, 108 (1), 361-6 PMID: 21173250
What is it that transforms a page full of words into an experience that moves us and leaves us changed? K. Okada From Words to Brain
... Read more »
Hoeft F, McCandliss BD, Black JM, Gantman A, Zakerani N, Hulme C, Lyytinen H, Whitfield-Gabrieli S, Glover GH, Reiss AL.... (2011) Neural systems predicting long-term outcome in dyslexia. Proceedings of the National Academy of Sciences of the United States of America, 108(1), 361-6. PMID: 21173250
- January 27, 2011
- 07:01 PM
- 400 views
Don't Assume that fMRI and MEG Will Give You Comparable Results
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate/Advanced
There are three common methods of studying brain function in normal human populations: fMRI, MEG, an EEG. There is surprisingly little crosstalk between the techniques, mostly due to practical issues.For better...
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Vartiainen J, Liljeström M, Koskinen M, Renvall H, & Salmelin R. (2011) Functional magnetic resonance imaging blood oxygenation level-dependent signal and magnetoencephalography evoked responses yield different neural functionality in reading. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31(3), 1048-58. PMID: 21248130
- January 24, 2011
- 06:41 PM
- 424 views
Recycling Neurons for Reading
by Livia in Reading and Word Recognition Research
Accesibility: Intermediate-Advanced
Our brains have evolved to be good at certain things: seeing, hearing, learning language, and interacting with other similar brains, to name a few examples. But say you want it to do something new – look at symbols...
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Dehaene S, Pegado F, Braga LW, Ventura P, Nunes Filho G, Jobert A, Dehaene-Lambertz G, Kolinsky R, Morais J, & Cohen L. (2010) How learning to read changes the cortical networks for vision and language. Science (New York, N.Y.), 330(6009), 1359-64. PMID: 21071632
- October 7, 2010
- 04:47 PM
- 528 views
White Matter and Reading Ability
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
Hello folks. Things are pretty busy over here and I might be having to review a lot of papers soon, so there's a possibility that entries here will get shorter and a bit more technical. But we'll...
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ANDREWS, J., BEN-SHACHAR, M., YEATMAN, J., FLOM, L., LUNA, B., & FELDMAN, H. (2009) Reading performance correlates with white-matter properties in preterm and term children. Developmental Medicine , 52(6). DOI: 10.1111/j.1469-8749.2009.03456.x
Rimrodt, S., Peterson, D., Denckla, M., Kaufmann, W., & Cutting, L. (2010) White matter microstructural differences linked to left perisylvian language network in children with dyslexia. Cortex, 46(6), 739-749. DOI: 10.1016/j.cortex.2009.07.008
- August 18, 2010
- 02:20 PM
- 577 views
Noise Exclusion Deficits in Dyslexia
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
The human visual system includes two pathways, magnocellular and parvocellular, deriving from two types of retinal ganglion cells that project to different layers of the lateral geniculate nucleus. ...
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Sperling, A., Lu, Z., Manis, F., & Seidenberg, M. (2005) Deficits in perceptual noise exclusion in developmental dyslexia. Nature Neuroscience. DOI: 10.1038/nn1474
- August 4, 2010
- 03:14 PM
- 464 views
Sensitivity and Specialization in the Occipitatemporal Region: Differences in Dyslexic Children
by Livia in Reading and Word Recognition Research
Accessibility: Advanced/intermediate
Early research on the role of the occipitotemporal region in reading often focused on characterizing a single region in the mid fusiform, commonly called the visual word form area. Since then, focus has gradually...
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van der Mark S, Bucher K, Maurer U, Schulz E, Brem S, Buckelmüller J, Kronbichler M, Loenneker T, Klaver P, Martin E.... (2009) Children with dyslexia lack multiple specializations along the visual word-form (VWF) system. NeuroImage, 47(4), 1940-9. PMID: 19446640
- July 8, 2010
- 06:28 PM
- 609 views
fMRI of Letter Processing in Children and Adults
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
How is letter processing different from word processing? Since letters compose words, many reading models have letter processing earlier in the reading stream, but there is still room for more imaging...
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Turkeltaub PE, Flowers DL, Lyon LG, & Eden GF. (2008) Development of ventral stream representations for single letters. Annals of the New York Academy of Sciences, 13-29. PMID: 19076386
- June 24, 2010
- 12:15 AM
- 585 views
A Meta-Analysis of Dyslexia Brain Imaging Studies
by Livia in Reading and Word Recognition Research
Accessibility: Advanced
fMRI experiments, with their small sample sizes, can easily fall victim to variability within the subject pool. This is especially true for patient studies. So it’s nice to step back and look at the big picture once in a...
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Richlan, F., Kronbichler, M., & Wimmer, H. (2009) Functional abnormalities in the dyslexic brain: A quantitative meta-analysis of neuroimaging studies. Human Brain Mapping, 30(10), 3299-3308. DOI: 10.1002/hbm.20752
- May 24, 2010
- 06:10 PM
- 527 views
Evidence Suggesting that Specialized Visual Regions Are Formed by Pruning in Early Childhood
by Livia in Reading and Word Recognition Research
There are quite a few specialized visual regions in the brain. For example, the fusiform face area (FFA) activates for faces, and the visual word form area (VWFA) in the left fusiform is consistently active for words.
How do these specialized...
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Cantlon JF, Pinel P, Dehaene S, & Pelphrey KA. (2010) Cortical Representations of Symbols, Objects, and Faces Are Pruned Back during Early Childhood. Cerebral cortex (New York, N.Y. : 1991). PMID: 20457691
- May 18, 2010
- 06:49 PM
- 409 views
Multimodal Investigation of Reading in Children: More from Brem and Colleagues
by Livia in Reading and Word Recognition Research
Accessibility: Advanced
Last time we read an article from Brem and colleagues that compared word processing in adolescents (age 15-17) and adults (19-30). In follow-up paper from 2009, Brem expanded the report to include children (9-11).
If you...
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Brem S, Halder P, Bucher K, Summers P, Martin E, & Brandeis D. (2009) Tuning of the visual word processing system: distinct developmental ERP and fMRI effects. Human brain mapping, 30(6), 1833-44. PMID: 19288464
- May 14, 2010
- 03:30 PM
- 749 views
Developmental Changes in Word Processing After Adolescence
by Livia in Reading and Word Recognition Research
When does brain development for reading stop? We often focus on school aged children, but what about the later teen years? To answer this question, Brem and colleagues tested adolescents (age 15-17) and adults (19-31) in a study using fMRI and...
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Brem S, Bucher K, Halder P, Summers P, Dietrich T, Martin E, & Brandeis D. (2006) Evidence for developmental changes in the visual word processing network beyond adolescence. NeuroImage, 29(3), 822-37. PMID: 16257546
- April 29, 2010
- 08:32 PM
- 668 views
Letter-sound Training in Children Causes Brain Specialization for Letters
by Livia in Reading and Word Recognition Research
My research focuses on the left occipitotemporal region. One area in this region, also commonly referred to as the visual word form area, has been shown to activate selectively for letters. Presumably, since reading is too recent a phenomenon to have...
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Brem S, Bach S, Kucian K, Guttorm TK, Martin E, Lyytinen H, Brandeis D, & Richardson U. (2010) Brain sensitivity to print emerges when children learn letter-speech sound correspondences. Proceedings of the National Academy of Sciences of the United States of America. PMID: 20395549
- April 21, 2010
- 06:42 PM
- 568 views
Posterior Brain Differences in Children with Dyslexia
by Livia in Reading and Word Recognition Research
Accessibility: Intermediate-Advanced
I realized after the last post that we haven’t actually spent much time discussing brain differences between dyslexic and nonimpaired readers. So today, I’m covering an earlier experiment by the...
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Shaywitz, B. (2002) Disruption of posterior brain systems for reading in children with developmental dyslexia. Biological Psychiatry, 52(2), 101-110. DOI: 10.1016/S0006-3223(02)01365-3
- April 15, 2010
- 12:07 PM
- 640 views
Phonological Training Changes Brain Activation in Dyslexic Children
by Livia in Reading and Word Recognition Research
Note: Online Universities has included me in their list of top 50 female science bloggers. It’s not actually for this blog, but for my Brain Science and Creative Writing blog. Anyways, check out the list if you get a chance. There are lot of interesting bloggers.
Accessibility: Intermediate-Advanced
We’ve looked at the neuroscience of dyslexia and how the dyslexic brain processes words.
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Shaywitz BA, Shaywitz SE, Blachman BA, Pugh KR, Fulbright RK, Skudlarski P, Mencl WE, Constable RT, Holahan JM, Marchione KE.... (2004) Development of left occipitotemporal systems for skilled reading in children after a phonologically- based intervention. Biological psychiatry, 55(9), 926-33. PMID: 15110736
- April 6, 2010
- 07:34 PM
- 592 views
The Development of Visual Word Recognition
by Livia in Reading and Word Recognition Research
We’ve looked at brain regions and development during word related tasks (word generation, reading and repeating), but we haven’t yet looked at a straight up study of word recognition and development.
What’s the best task to use to study visual word recognition? You can have people read out loud, but that involves processes like speech generation. Likewise, reading sentences or paragraphs
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Turkeltaub, P., Gareau, L., Flowers, D., Zeffiro, T., & Eden, G. (2003) Development of neural mechanisms for reading. Nature Neuroscience, 6(7), 767-773. DOI: 10.1038/nn1065
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