The Role of Right and Left Parietal Lobes in the Conceptual Processing of Numbers

Cappelletti, Marinella; Lee, Hwee Ling; Freeman, Elliot; Price, Cathy J.

doi:10.1162/jocn.2009.21246

Cited by 81 publications

(84 citation statements)

References 56 publications

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“…The numerical decision task in the context of this study (odd or even) uses number semantics, which are represented in parietal cortex (Cappelletti et al, 2010). A previous study that investigated parietal cortex involvement in a range of different tasks that included converting orthography to phonology and a number task (although, in that instance, a simple subtraction) demonstrated parietal activity for both phonology and numbers (Simon et al, 2002).…”

Section: Discussionmentioning

confidence: 92%

An Investigation of Twenty/20 Vision in Reading

Hellyer

Woodhead²,

Leech³

et al. 2011

J. Neurosci.

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One functional anatomical model of reading, drawing on human neuropsychological and neuroimaging data, proposes that a region in left ventral occipitotemporal cortex (vOT) becomes, through experience, specialized for written word perception. We tested this hypothesis by presenting numbers in orthographical and digital form with two task demands, phonological and numerical. We observed a main effect of task on left vOT activity but not stimulus type, with increased activity during the phonological task that was also associated with increased activity in the left inferior frontal gyrus, a region implicated in speech production. Region-of-interest analysis confirmed that there was equal activity for orthographical and digital written forms in the left vOT during the phonological task, despite greater visual complexity of the orthographical forms. This evidence is incompatible with a predominantly feedforward model of written word recognition that proposes that the left vOT is a specialized cortical module for word recognition in literate subjects. Rather, the physiological data presented here fits better with interactive computational models of reading that propose that written word recognition emerges from bidirectional interactions between three processes: visual, phonological, and semantic. Further, the present study is in accord with others that indicate that the left vOT is a route through which nonlinguistic stimuli, perhaps high contrast two-dimensional objects in particular, gain access to a predominantly left-lateralized language and semantic system.

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Section: Discussionmentioning

confidence: 92%

An Investigation of Twenty/20 Vision in Reading

Hellyer

Woodhead²,

Leech³

et al. 2011

J. Neurosci.

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“…First, patients with parietal lesions consistently show selective impairments in numerical skills (e.g., Dehaene and Cohen, 1997;Denes and Signorini, 2001;Grafman et al, 1982;Takayama et al, 1994;Warrington, 1982;Zorzi et al, 2002), whereas patients with lesions to other brain regions showed preservation of numerical skills (e.g., Butterworth et al, 2001;Cappelletti et al, 2001Cappelletti et al, , 2002Cappelletti et al, , 2005Crutch and Warrington, 2002;Diesfeldt, 1993;Jefferies et al, 2004Jefferies et al, , 2005Lemer et al, 2003;Zamarian et al, 2006). Second, functional MRI studies have systematically shown that numerical processing elicits greater activation in the parietal lobule than does nonnumerical processing (e.g., Ansari et al, 2006;Cappelletti et al, 2010;Eger et al, 2003;Knops et al, 2006;Le Clec'H et al, 2000;Piazza et al, 2004;Thioux et al, 2005;Zago et al, 2008; but see Göbel et al, 2004;Kadosh et al, 2008;Shuman and Kanwisher, 2004). Third, developmental dyscalculia has also been showed to be associated with structural abnormalities in the IPS regions (e.g., Isaacs et al, 2001;Kucian et al, 2006;Molko et al, 2003Molko et al, , 2004Rotzer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Neural correlates of numbers and mathematical terms

2012

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Numerical processing has been demonstrated to be subserved typically by the brain regions around the bilateral intraparietal sulcus (IPS). The goal of the current study was to investigate whether the processing of mathematical terms shared the same brain regions with numerical processing. Healthy adult participants performed semantic distance judgment tasks on five types of materials, including geometric terms, algebraic terms, linguistic terms, words for tools and other common objects, and Arabic numbers. Brain activation was measured with functional magnetic resonance imaging (fMRI). The results showed that geometric terms had greater activation than algebraic terms, linguistic terms and tool words in the horizontal IPS, but algebraic terms did not have greater activation than linguistic terms and tool words in this region. Arabic numbers showed greater activation than non-number materials (including geometric terms, algebraic terms, linguistic terms and tool words) in the bilateral IPS, right inferior frontal gyrus and bilateral middle frontal gyrus, but the non-number materials showed stronger activation in the left inferior frontal gyrus and left middle temporal gyrus. These results suggest that the brain area for the processing of numbers (the left IPS) seems to be involved in semantic processing of geometric terms, but not that of other mathematical terms such as algebraic terms. Both algebraic and geometric terms share similar brain organization with basic semantic processing in the left temporal and frontal regions.

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“…The present study required a baseline task that resulted in little or no activity in the reading-related pathways, which were known to include the posteroanterior extents of the left fusiform gyrus and superior temporal sulcus (Spitsyna et al, 2006). Visually presented numbers are like words and false font in that they consist of two-dimensional symbols with high contrast and spatial frequency, but processing of number-related semantics occurs in parietal cortex (Thioux et al, 2005;Cappelletti et al, 2010). Therefore, the study design was predicated on the assumption that explicit processing of visually presented numbers would result in low activity in the reading-related temporal lobe pathways, allowing the visualization of the extent of temporal lobe activity in response to both false font and words.…”

Section: Discussionmentioning

confidence: 99%

“…The other familiar symbols conveying visual information at high spatial frequencies are numbers, but number semantics are processed in parietal cortex (Thioux et al, 2005;Cappelletti et al, 2010). The localist model would predict that activity in ventral and lateral temporal neocortex would follow the profile words Ͼ false font ϭ numbers; in contrast, a profile of words Ͼ false font Ͼ numbers would be evidence against a localist model.…”

Section: Introductionmentioning

confidence: 99%

The Visual Word Form System in Context

Woodhead

Brownsett²,

Dhanjal³

et al. 2011

J. Neurosci.

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According to the "modular" hypothesis, reading is a serial feedforward process, with part of left ventral occipitotemporal cortex the earliest component tuned to familiar orthographic stimuli. Beyond this region, the model predicts no response to arrays of false font in reading-related neural pathways. An alternative "connectionist" hypothesis proposes that reading depends on interactions between feedforward projections from visual cortex and feedback projections from phonological and semantic systems, with no visual component exclusive to orthographic stimuli. This is compatible with automatic processing of false font throughout visual and heteromodal sensory pathways that support reading, in which responses to words may be greater than, but not exclusive of, responses to false font. This functional imaging study investigated these alternative hypotheses by using narrative texts and equivalent arrays of false font and varying the hemifield of presentation using rapid serial visual presentation. The "null" baseline comprised a decision on visually presented numbers. Preferential activity for narratives relative to false font, insensitive to hemifield of presentation, was distributed along the ventral left temporal lobe and along the extent of both superior temporal sulci. Throughout this system, activity during the false font conditions was significantly greater than during the number task, with activity specific to the number task confined to the intraparietal sulci. Therefore, both words and false font are extensively processed along the same temporal neocortical pathways, separate from the more dorsal pathways that process numbers. These results are incompatible with a serial, feedforward model of reading.

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The Role of Right and Left Parietal Lobes in the Conceptual Processing of Numbers

Cited by 81 publications

References 56 publications

An Investigation of Twenty/20 Vision in Reading

An Investigation of Twenty/20 Vision in Reading

Neural correlates of numbers and mathematical terms

The Visual Word Form System in Context

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