Arithmetic and the brain

Institut National de la Santé et de la Recherche Médicale unit 562 Cognitive neuroimaging, Service Hospitalier Frederic Joliot, Commissariat à l'énergie atomique/DRM/DSV, 4 Place du general Leclerc, 91401 Orsay cedex, France.
Current Opinion in Neurobiology (Impact Factor: 6.63). 05/2004; 14(2):218-24. DOI: 10.1016/j.conb.2004.03.008
Source: PubMed

ABSTRACT Recent studies in human neuroimaging, primate neurophysiology, and developmental neuropsychology indicate that the human ability for arithmetic has a tangible cerebral substrate. The human intraparietal sulcus is systematically activated in all number tasks and could host a central amodal representation of quantity. Areas of the precentral and inferior prefrontal cortex also activate when subjects engage in mental calculation. A monkey analogue of these parieto-frontal regions has recently been identified, and a neuronal population code for number has been characterized. Finally, pathologies of this system, leading to acalculia in adults or to developmental dyscalculia in children, are beginning to be understood, thus paving the way for brain-oriented intervention studies.

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Available from: Laurent Cohen, Sep 29, 2015
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    • "To accomplish the second goal, the trials of the Add/Sub task were classified into four categories based on a 2 by 2 design, crossing 'Operation Type' (Addition vs. Subtraction) and 'Regrouping' (whether or not Carrying or Borrowing is needed). We hypothesized that Subtraction (compared to Addition) and Regrouping (compared to No-Regrouping) conditions would evoke more quantitative processing because it tends to be less practiced and less automatized (Ashkenazi et al. 2014; Dehaene et al. 2004; Duffau et al. 2002; van Harskamp and Cipolotti 2001). Thus, we expected to see stronger correlations between ANS acuity and calculations involving Subtraction (compared to Addition) and Regrouping (Carrying or Borrowing). "
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    • "Based on human neuroimaging, primate neurophysiology, and developmental neuropsychology studies, the TCM assumes that the parietal cortex hosts an abstract semantic representation of numerosities (Ansari et al., 2006; Dehaene et al., 2004; Fias et al., 2001; Nieder, 2012; Nieder et al., 2006; Piazza et al., 2006, 2007). This representation has been claimed to be notation (e.g., Arabic digit or dot-arrays), format (i.e., simultaneous or sequential presentation), and modality (e.g., visual or spoken number words) independent (i.e., abstract; Dehaene et al., 2004; Eger et al., 2003, 2009; Piazza et al., 2007). However, recent neuroimaging studies have challenged the idea of a universally abstract magnitude representation. "
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    ABSTRACT: It has been widely debated whether parietal cortex stores an abstract representation of numerosity that is activated for Arabic digits as well as for non-symbolic stimuli in a sensory modality independent fashion. Some studies suggest that numerical information in time-invariant (simultaneous) symbolic and non-symbolic visual stimuli is represented in the parietal cortex. In humans, whether the same representation is activated for time-variant (sequential) stimuli and for stimuli coming from different modalities has not been determined. To investigate this idea, we measured the brain activation of healthy adults performing estimation and/or comparison of sequential visual (series of dots) and auditory (series of beeps) numerosities. Our experimental design allowed us to separate numerosity estimation from comparison and response related factors. The BOLD signal in parietal cortex increased only when participants were engaged in the comparison of two consecutive numerosities that required a response. Using multivariate pattern analysis we trained a classifier to decode numerosity in various regions of interest (ROI). We failed to find any parietal ROI where the classifier could decode numerosities during the estimation phase. Rather, when participants were not engaged in comparison we were able to decode numerosity in an auditory cortex ROI for auditory stimuli and in a visual cortex ROI for visual stimuli. On the other hand, during the response period the classifier successfully decoded numerosity information in a parietal ROI for both visual and auditory numerosities. These results were further confirmed by support vector regression. In sum, our study does not support the involvement of the parietal cortex during estimation of sequential numerosity in the absence of an active task with a response requirement. Copyright © 2015. Published by Elsevier Inc.
    NeuroImage 04/2015; 116. DOI:10.1016/j.neuroimage.2015.04.019 · 6.36 Impact Factor
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    • "With regard to the brain structures, involved in the calculation process , Dehaene et al. (2004) demonstrated that the intraparietal sulcus , the precentral and inferior prefrontal cortex are being systematically activated in calculation tasks hosting central amodal representation of quantity. Findings of the studies on arithmetical processing indicate that mental calculation is associated with increased gamma oscillations (Micheloyannis et al., 2003; Dimitriadis et al., 2012) sub-serving calculation-related attention. "
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    ABSTRACT: To evaluate the spectral power of the cortical bands in patients with first episode schizophrenia and schizoaffective disorder at rest and during the performance of a mental arithmetic task. We analyzed EEG spectral power (SP) in the resting state and subsequently while counting down from 200 in steps of 7, in 32 first episode schizophrenia patients (SZ), 32 patients with first episode schizoaffective disorder (SA) and healthy controls (HC, n=40). Behavioral parameters such as accuracy and counting speed were also evaluated. Both SZ and SA patients were slower in counting than HC, no difference was obtained in the accuracy and counting speed in the patient groups. In the resting state patients showed elevated midline theta power, off-midline anterior beta 2 power and decreased central/posterior alpha power. The SA group occupied an intermediate position between the schizophrenia patients and controls. In task performance patients lacked a typical increase of midline theta, left anterior beta 2, and anterior gamma power; however, schizoaffective patients demonstrated a growing trend of power in the gamma band in left anterior off-midline sites similar to HC. Moreover, alpha power was less inhibited in schizoaffective patients and more pronounced in schizophrenia patients indicating distinct inhibitory mechanisms in these psychotic disorders. Patients with SA demonstrate less alteration in the spectral power of bands at rest than SZ, and present spectral power changes during cognitive task performance close to the controls. Our study contributes to the present evidence on the neurophysiological distinction between schizophrenia and schizoaffective disorder. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
    Clinical Neurophysiology 02/2015; DOI:10.1016/j.clinph.2014.12.031 · 3.10 Impact Factor
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