Disrupted neural responses to phonological and orthographic processing in dyslexic children: an fMRI study

“This neurobiological evidence of dysfunction in left hemisphere posterior reading circuits is already present in reading disabled children and cannot be ascribed simply to a lifetime of poor reading (Seki, et al., 2001; B. A. Shaywitz, et al., 2002; Simos, et al., 2000; Temple, et al., 2001 ).”

“At the level of the brain, this cognitive deficit would arise from a congenital dysfunction of certain cortical areas involved in phonology and reading [4–6].”

“Phonological processing is often compromised after perisylvian damage (Blumstein, 1994) and has been linked to a left perisylvian network in neuroimaging studies in children (Shaywitz et al., 2002; Temple et al., 2001).”

“…brain system is known to mediate grapheme-phoneme conversions and fine-grained phonemic analysis [Booth et al., 2004; Eden et al., 2004; Poldrack et al., 2001; Price, 2000; Shaywitz et al., 1998; Simos et al., 2000, 2002; Temple et al., 2001, 2003; Tan et al., 2003; Xu et al., 2001, 2002].”

“…et al., 2006; Nakamura, Dehaene, Jobert, Le Bihan, & Kouider, in press; Nakamura et al., 2006; Paulesu et al., 2001; Rumsey et al., 1992; Salmelin, Service, Kiesila, Uutela, & Salonen, 1996; Seki et al., 2001; Shaywitz et al., 1998, 2002b, 2003; Temple et al., 2000, 2001; Xu et al., 2001).”

“…group comparisons using substantially smaller samples of children, they provide some support for the previously reported findings of NI > RD activation for left perisylvian (Temple 2001, Backes et al. 2002) and left ventral occipitotemporal regions (Temple et al. 2001, but see Backes et al. 2002).”

“It appears to be late developing in reading acquisition and is aptly referred to as the occipitotemporal ‘‘skill zone’’ [Grigorenko, 2001; Sandak et al., 2004; Schlaggar and McCandliss, 2007; Shaywitz et al., 2002, 2007].”

“This region may function for words in an analogous manner to the right hemisphere fusiform face area for expertise (Gauthier 2000; Gauthier et al 2000; Tarr and Gauthier 2000 ).”

“…reported underactivations for only one such baseline contrast (Booth et al., 2007; Brambati et al., 2006; Cao et al., 2006; Hoeft et al., 2006; Ingvar et al., 2002; Maurer et al., 2010; McCrory et al., 2005; Meyler et al., 2008; Paulesu et al., 2001; Schulz et al., 2009; Temple et al., 2001).”

“Lower VIQ scores have been reported previously in children with dyslexia, and were not found to relate to degree of phonological deficits or functional imaging findings (Temple et al., 2001).”

“In dyslexic children, a functional magnetic resonance imaging (fMRI) study during phonological and orthographic tasks of rhyming and matching visually presented letter pairs demonstrated significant differences in the activation of cortical regions (342, 343).”

“…al., 2004; Flowers et al., under review; Pugh et al., 2000; Rumsey et al., 1997b; Shaywitz et al., 2002; Simos et al., 2000a; Simos et al., 2000b; Temple et al., 2001), inferior occipitotemporal cortex (Brunswick et al., 1999; McCrory, Mechelli, Frith, & Price, 2005; Paulesu et al., 2001;…”

“…2006; Rubia et al., 2007) and, in particular, reduced activation in temporal lobe regions (Shafritz et al., 2004); differences of activation in the same areas are associated with neural deficits in dyslexia (Temple et al., 2001; Shaywitz et al., 2002; Kronbichler et al., 2006; Hoeft et al., 2007).”

“The visual response to letters in fusiform gyrus explained about 11% additional variance beyond the variance already explained through the auditory response and the congruency effect in planum temporale/Heschl sulcus.”

“Studies have also analyzed differences in patterns of brain activation between normal children and children with dyslexia (Temple et al., 2001) or attention-deficit hyperactivity disorder (Vaidya et al., 1998).”

“Similarly, the literature-based ROI in the left superior temporal gyrus was located in a region of perisylvian cortex that is active in typically developing children during reading and phonology tasks ( Temple et al., 2001; Turkeltaub et al., 2003).”

“For example, there is broad consensus that disruption of the neural pathways located in the left temporo-parietal cortex is linked with dyslexia [74, 105, 110, 111, 120].”

“…activation in children with dyslexia which suggests that this brain abnormality may in fact be fundamentally related to the early development of reading disorders (Backes et al., 2002; Georgiewa et al., 1999; Shaywitz et al., 2002; Simos et al., 2002b; Temple et al., 2001; Turkeltaub et al., 2003).”

“Developmental neuroimaging studies of reading have revealed that the left angular gyrus is consistently activated during phonological awareness tasks (Shaywitz et al., 1998; Temple et al., 2001), and that this activation is related to performance differences in phonological awareness tasks and reading ability (Turkelt…”

“PS, Dev Simos et al. (2001) 7–17-year-old children/pseudoword rhyme-matching MEG Initially, dyslexic children showed decreased left STG activity relative to controls.”

“The praise relates to the authors’ insistence that in cases of congenital disorders that affect the brain, behavioral impairments at the endpoint of development are likely to be the outcome of an extended atypical developmental trajectory, determined by the initial structural anomalies in the system and by its atypica…”

“Other neuroimaging studies of dyslexic children have used similar criteria (Simos et al., 2000a,b, 2002; Temple et al., 2001, 2003; Shaywitz et al., 2002, 2004; Aylward et al., 2003).”

“Several studies have also demonstrated reduced activity of left temporoparietal regions (including the angular and supramarginal gyri) on tasks of word reading, non-word reading and letter rhyming [171, 172, 187], and left occipitoparietal regions on tasks of letter matching [187].”

“, 1995) and fMRI (Temple et al., 2001; Temple, 2002; Poldrack et al., 2001; Gaab et al., 2007; Tallal and Gaab, 2006).”

“This article highlights key findings regarding the functional role of these regions during skilled reading, the developmental trajectory toward this mature reading circuitry in normally developing children, deviations from this trajectory in populations with reading disabilities, and the ways in…”

“Therefore, we included the 17 published papers [42–58] from Richlan et al.”

“Before training, the children with developmental dyslexia exhibited an absence of the left temporoparietal activation and a displacement of the left prefrontal activation exhibited by typical-reading children performing a phonological task (Temple et al., 2001).”

“The involvement of temporal and tempororparietal regions in dyslexia was also found in functional neuroimaging studies [e.g., Rumsey et al., 1997; Shaywitz et al., 2002; Temple et al., 2001].”

“Although reduced activation in left fusiform gyrus for patients with dyslexia may reflect a deficit in orthographic processing, some studies have shown normal activation in this region during letter rhyming judgment (Temple et al., 2001) or non-word reading (Georgiewa et al.”

“REVIEW ARTICLE published: 11 November 2014 doi: 10.3389/fnhum.2014.00830 Reading the dyslexic brain: multiple dysfunctional routes revealed by a new meta-analysis of PET and fMRI activation studies”

“Using electroencephalography-based event-related imaging, we investigated how tuning of visual activity for print advances in the same children before and after initial reading training in school.”

“Our findings are consistent with substantial, converging evidence, including a prior neuroimaging study (Temple et al., 2001), and this consistency suggests that the relationship between IQ and the phonological-awareness deficit underlying dyslexia may be quite weak (O’Malley et al., 2002; Stuebing…”

“including posterior temporal and parietal regions as being important for reading due to their engagement for tasks involving phonological analysis of print and their reduced engagement in dyslexic readers (Pugh et al. 2000; Temple et al. 2001; Shaywitz et al. 2002; Shaywitz et al. 2004; Cao et al. 2006; Hoeft et al. 2…”

“Particularly, cortical and subcortical brain regions, including frontal, temporal and parietal cortices, as well as insula and cerebellum seem to be significantly affected in individuals with DD, supporting the phonological processing deficit model of DD (Paulesu et al., 1996; Brunswick et al., 1999; Temple et al., 20…”

“…and frontal-temporal-occipital reading systems (Aylward et al., 2003; Georgiewa et al., 2002; Richards et al., 2002; Shaywitz et al., 1998; Temple et al., 2001; Turkeltaub et al., 2002, 2003), which may receive crucial contributions from the cerebellum (Nicolson et al., 1999; McCrory et…”

“, [65]) and, similarly, investigations focused on understanding the origin of dyscalculia rarely consider the reading skills of children (see e.”

“[68] who scanned dyslexic children and normal controls performing a rhyme task on visual presented letters.”

“…the phonological deficit hypothesis (Bradley and Bryant, 1978; Ramus et al., 2003), brain imaging studies have revealed reduced temporo-parietal activation in phonological tasks that was associatedwith dyslexia (Rumsey et al., 1997; Shaywitz et al., 1998; Temple et al., 2001; Hoeft et al., 2007).”

“Signal change ivation in dyslexic readers (e.g., Rumsey et al., 1997; Shaywitz t al., 2002; Temple et al., 2001; Temple, 2002).”

“…reveal reduced activation in response to words or word-like stimuli within posterior parts of the reading network in the brain of adults and older children with reading disability (Brambati et al., 2006; Brunswick et al., 1999; Rumsey et al., 1997; Shaywitz et al., 2002, 1998; Temple et al., 2001).”

“It seems that our data support a role for the supramarginal gyrus in phonological processing with visually presented words, a finding that is closest to that of Temple et al. (2001).”

“…to findings of altered language lateralization in children with language impairment or dylexia (Frye et al., 2009; Gabrieli, 2009; Georgiewa et al., 1999; Shaywitz et al., 2002; Temple et al., 2001): In these studies, right-hemispheric language involvement was associated with language pathology.”

“Using fMRI during a phonological task, Temple (2001) [148], reported reduced left temporo-parietal activity in 8- to 12-year-old children with dyslexia compared to normal reading children.”

“In children, phonological tasks such as non-word reading, phoneme deletion and rhyming judgment resulted in the activation of left temporo-parietal and frontal regions (Booth et al., 2004; Georgiewa, 1999; Shaywitz et al., 2002; Temple et al., 2001).”

“…tasks involving letters and words (e.g., Paulesu et al. 1996; Rumsey et al. 1997; Shaywitz et al. 1998, 2002, 2003, 2004; Brunswick et al. 1999; Georgiewa et al. 1999; Pugh 2000; Simos et al. 2000, 2002; Corina et al. 2001; Temple et al. 2001, 2003; Aylward et al. 2003; Eden et al. 2004).”

“Given the well-documented disruption to the posterior word form center (e.g., B. Shaywitz et al., 2002; Temple et al., 2001), one of the goals of our research group has been to disentangle the three word forms—phonological, orthographic, and morphological (see Figure 2)—that contribute to word…”

“(5) compared normal-reading and dyslexic children on three tasks: a rhyming judgment task (emphasizing phonological processing); a letter-matching task (emphasizing orthographic processing); and a line-matching baseline task.”

“The same regions were active for children in phonological tasks such as nonword reading, phoneme deletion, and rhyming judgment (Booth et al., 2004; Georgiewa, 1999; Shaywitz et al., 2002; Temple et al., 2001).”

“…studies have found reduced activation, in contrast to controls, in the left temporo-parietal junction in dyslexic adults (Rumsey et al., 1992, 1997; Paulesu et al., 1996, 2001; Shaywitz et al., 1998, 2002, 2003; Brunswick et al., 1999) and children (Simos et al., 2000; Temple et al., 2001).”

“One approach to this has been to measure neural responses during visual-rhyme judgment, given that both orthographic and phonological representations must be accessed to perform the task (Cao et al., 2006; Hoeft et al., 2006; Simos et al., 2000; Temple et al., 2001, 2003).”

“In addition, the use of head restraint systems or motion training paired with feedback systems in the mock scanner have shown promising findings on motion artifacts (Slifer et al., 1993; Temple et al., 2001).”

“In typically developing children, the posterior dorsal region is recruited in letter rhyming (Temple et al., 2001) and implicit word reading (Turkeltaub et al., 2003) tasks, while underactivation of this area is reported in children with developmental dyslexia (Hoeft et al., 2006; Shaywitz et al.,…”

“…1992; Wimmer 1993; Esser & Schmidt 1994; Wagner et al. 1994), as well as by using brain imaging techniques (Price et al. 1994; Rumsey et al. 1994, 1997; Salmelin et al. 1996; Demp et al. 1997; Shaywitz et al. 1998; Fiez et al. 1999; Georgiewa et al. 1999; Helenius et al. 1999; Temple et al. 2001).”

“... Treiman & Cassar, 1996); orthographicdefined as coding and analysis of letters in written words (Berninger, 1987; Berninger et al., 1992; Caravolas, Kessler, Hulme, & Snowling, 2005; Holmes & Davis, 2002; Jaffre ´ & Fayol, 2006; Johnson, 1986; Olson, Forsberg, & Wise, 1994; Olson, Forsberg, Wise, et al., 1994; Ols…”

“Given the well-documented disruption to the posterior word form center (e.g. Shaywitz et al., 2002; Temple et al., 2001), one of the goals of our research group has been to disentangle the brain basis of three word forms—phonological, orthographic, and morphological—that contribute to effective…”

“Many have argued that the central deficit in reading disorder is phonological processing (Paulesu et al., 2001; Pugh et al., 2000; Shaywitz et al., 1998; Temple et al., 2001) and less attention has been given to whether children with reading disorders have deficits in semantic processing.”

“[122] recorded whole-brain imaging data in 24 dyslexic and 15 normally reading children (8–12 years old) during phonological and orthographic tasks of rhyming and matching visually presented consonant letter pairs (e.”

“In a recent meta-analysis of all neuroimaging studies on dyslexia published until September 2013, only three studies investigated letter-string processing with minimal lexical or phonological involvement (Peyrin et al., 2012; Reilhac et al., 2013; Temple et al., 2001).”